2019-06-03 21:27:46 +00:00
|
|
|
A8 over A8
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
12 values:
|
|
|
|
v0 = load8 arg(0)
|
|
|
|
v1 = to_f32 v0
|
|
|
|
v2 = mul_f32 v1 3B808081 (0.0039215689)
|
|
|
|
v3 = load8 arg(1)
|
|
|
|
v4 = to_f32 v3
|
|
|
|
v5 = mul_f32 v4 3B808081 (0.0039215689)
|
|
|
|
↑ v6 = splat 3F800000 (1)
|
|
|
|
v7 = sub_f32 v6 v2
|
|
|
|
v8 = mad_f32 v5 v7 v2
|
|
|
|
v9 = mul_f32 v8 437F0000 (255)
|
|
|
|
v10 = round v9
|
|
|
|
store8 arg(1) v10
|
2019-06-10 17:05:48 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
4 registers, 12 instructions:
|
|
|
|
r0 = splat 3F800000 (1)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r1 = load8 arg(0)
|
|
|
|
r1 = to_f32 r1
|
|
|
|
r1 = mul_f32 r1 3B808081 (0.0039215689)
|
|
|
|
r2 = load8 arg(1)
|
|
|
|
r2 = to_f32 r2
|
|
|
|
r2 = mul_f32 r2 3B808081 (0.0039215689)
|
|
|
|
r3 = sub_f32 r0 r1
|
|
|
|
r1 = mad_f32 r2 r3 r1
|
|
|
|
r1 = mul_f32 r1 437F0000 (255)
|
|
|
|
r1 = round r1
|
|
|
|
store8 arg(1) r1
|
|
|
|
|
|
|
|
A8 over G8
|
|
|
|
17 values:
|
|
|
|
v0 = load8 arg(1)
|
|
|
|
v1 = to_f32 v0
|
|
|
|
v2 = mul_f32 v1 3B808081 (0.0039215689)
|
|
|
|
v3 = load8 arg(0)
|
|
|
|
v4 = to_f32 v3
|
|
|
|
v5 = mul_f32 v4 3B808081 (0.0039215689)
|
|
|
|
↑ v6 = splat 3F800000 (1)
|
|
|
|
v7 = sub_f32 v6 v5
|
|
|
|
v8 = mul_f32 v2 v7
|
|
|
|
↑ v9 = splat 3E59B3D0 (0.21259999)
|
|
|
|
↑ v10 = splat 3F371759 (0.71520001)
|
|
|
|
v11 = mul_f32 v8 3D93DD98 (0.0722)
|
|
|
|
v12 = mad_f32 v8 v10 v11
|
|
|
|
v13 = mad_f32 v8 v9 v12
|
|
|
|
v14 = mul_f32 v13 437F0000 (255)
|
|
|
|
v15 = round v14
|
|
|
|
store8 arg(1) v15
|
|
|
|
|
|
|
|
5 registers, 17 instructions:
|
|
|
|
r0 = splat 3F800000 (1)
|
|
|
|
r1 = splat 3E59B3D0 (0.21259999)
|
|
|
|
r2 = splat 3F371759 (0.71520001)
|
|
|
|
loop:
|
|
|
|
r3 = load8 arg(1)
|
2019-11-08 20:18:06 +00:00
|
|
|
r3 = to_f32 r3
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r4 = load8 arg(0)
|
2019-11-05 02:14:24 +00:00
|
|
|
r4 = to_f32 r4
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r4 = mul_f32 r4 3B808081 (0.0039215689)
|
|
|
|
r4 = sub_f32 r0 r4
|
|
|
|
r4 = mul_f32 r3 r4
|
|
|
|
r3 = mul_f32 r4 3D93DD98 (0.0722)
|
|
|
|
r3 = mad_f32 r4 r2 r3
|
|
|
|
r3 = mad_f32 r4 r1 r3
|
|
|
|
r3 = mul_f32 r3 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r3 = round r3
|
|
|
|
store8 arg(1) r3
|
2019-06-03 21:27:46 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
A8 over RGBA_8888
|
|
|
|
35 values:
|
|
|
|
v0 = load32 arg(1)
|
|
|
|
↑ v1 = splat FF (3.5733111e-43)
|
|
|
|
v2 = extract v0 0 v1
|
|
|
|
v3 = to_f32 v2
|
|
|
|
v4 = mul_f32 v3 3B808081 (0.0039215689)
|
|
|
|
v5 = load8 arg(0)
|
|
|
|
v6 = to_f32 v5
|
|
|
|
v7 = mul_f32 v6 3B808081 (0.0039215689)
|
|
|
|
↑ v8 = splat 3F800000 (1)
|
|
|
|
v9 = sub_f32 v8 v7
|
|
|
|
v10 = mul_f32 v4 v9
|
|
|
|
v11 = mul_f32 v10 437F0000 (255)
|
|
|
|
v12 = round v11
|
|
|
|
v13 = extract v0 8 v1
|
|
|
|
v14 = to_f32 v13
|
|
|
|
v15 = mul_f32 v14 3B808081 (0.0039215689)
|
|
|
|
v16 = mul_f32 v15 v9
|
|
|
|
v17 = mul_f32 v16 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
v18 = round v17
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
v19 = pack v12 v18 8
|
|
|
|
v20 = extract v0 16 v1
|
|
|
|
v21 = to_f32 v20
|
|
|
|
v22 = mul_f32 v21 3B808081 (0.0039215689)
|
|
|
|
v23 = mul_f32 v22 v9
|
|
|
|
v24 = mul_f32 v23 437F0000 (255)
|
|
|
|
v25 = round v24
|
|
|
|
v26 = extract v0 24 v1
|
|
|
|
v27 = to_f32 v26
|
|
|
|
v28 = mul_f32 v27 3B808081 (0.0039215689)
|
|
|
|
v29 = mad_f32 v28 v9 v7
|
|
|
|
v30 = mul_f32 v29 437F0000 (255)
|
|
|
|
v31 = round v30
|
|
|
|
v32 = pack v25 v31 8
|
|
|
|
v33 = pack v19 v32 16
|
|
|
|
store32 arg(1) v33
|
2019-06-10 17:05:48 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
7 registers, 35 instructions:
|
|
|
|
r0 = splat FF (3.5733111e-43)
|
2019-06-03 21:32:49 +00:00
|
|
|
r1 = splat 3F800000 (1)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r2 = load32 arg(1)
|
|
|
|
r3 = extract r2 0 r0
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r4 = load8 arg(0)
|
|
|
|
r4 = to_f32 r4
|
|
|
|
r4 = mul_f32 r4 3B808081 (0.0039215689)
|
|
|
|
r5 = sub_f32 r1 r4
|
|
|
|
r3 = mul_f32 r3 r5
|
|
|
|
r3 = mul_f32 r3 437F0000 (255)
|
|
|
|
r3 = round r3
|
|
|
|
r6 = extract r2 8 r0
|
2019-11-08 20:18:06 +00:00
|
|
|
r6 = to_f32 r6
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r6 = mul_f32 r6 3B808081 (0.0039215689)
|
2019-11-08 20:18:06 +00:00
|
|
|
r6 = mul_f32 r6 r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r6 = mul_f32 r6 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r6 = round r6
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r6 = pack r3 r6 8
|
|
|
|
r3 = extract r2 16 r0
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r3 = mul_f32 r3 r5
|
|
|
|
r3 = mul_f32 r3 437F0000 (255)
|
|
|
|
r3 = round r3
|
|
|
|
r2 = extract r2 24 r0
|
|
|
|
r2 = to_f32 r2
|
|
|
|
r2 = mul_f32 r2 3B808081 (0.0039215689)
|
|
|
|
r4 = mad_f32 r2 r5 r4
|
|
|
|
r4 = mul_f32 r4 437F0000 (255)
|
|
|
|
r4 = round r4
|
|
|
|
r4 = pack r3 r4 8
|
|
|
|
r4 = pack r6 r4 16
|
|
|
|
store32 arg(1) r4
|
2019-06-03 21:27:46 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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G8 over A8
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9 values:
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↑ v0 = splat 3F800000 (1)
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v1 = load8 arg(1)
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v2 = to_f32 v1
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v3 = mul_f32 v2 3B808081 (0.0039215689)
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↑ v4 = sub_f32 v0 v0
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v5 = mad_f32 v3 v4 v0
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v6 = mul_f32 v5 437F0000 (255)
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v7 = round v6
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store8 arg(1) v7
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2019-06-10 17:05:48 +00:00
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|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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3 registers, 9 instructions:
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r0 = splat 3F800000 (1)
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r1 = sub_f32 r0 r0
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2019-06-05 15:47:46 +00:00
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loop:
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sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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r2 = load8 arg(1)
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r2 = to_f32 r2
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r2 = mul_f32 r2 3B808081 (0.0039215689)
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r2 = mad_f32 r2 r1 r0
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r2 = mul_f32 r2 437F0000 (255)
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r2 = round r2
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store8 arg(1) r2
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2019-06-03 21:27:46 +00:00
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sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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G8 over G8
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17 values:
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v0 = load8 arg(0)
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v1 = to_f32 v0
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v2 = mul_f32 v1 3B808081 (0.0039215689)
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v3 = load8 arg(1)
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v4 = to_f32 v3
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v5 = mul_f32 v4 3B808081 (0.0039215689)
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↟ v6 = splat 3F800000 (1)
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↑ v7 = sub_f32 v6 v6
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v8 = mad_f32 v5 v7 v2
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↑ v9 = splat 3E59B3D0 (0.21259999)
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↑ v10 = splat 3F371759 (0.71520001)
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v11 = mul_f32 v8 3D93DD98 (0.0722)
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v12 = mad_f32 v8 v10 v11
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v13 = mad_f32 v8 v9 v12
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v14 = mul_f32 v13 437F0000 (255)
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v15 = round v14
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store8 arg(1) v15
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2019-06-10 17:05:48 +00:00
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|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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5 registers, 17 instructions:
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reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
r0 = splat 3F800000 (1)
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r0 = sub_f32 r0 r0
|
|
|
|
r1 = splat 3E59B3D0 (0.21259999)
|
|
|
|
r2 = splat 3F371759 (0.71520001)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r3 = load8 arg(0)
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
2019-11-08 20:18:06 +00:00
|
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|
r4 = load8 arg(1)
|
|
|
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r4 = to_f32 r4
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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r4 = mul_f32 r4 3B808081 (0.0039215689)
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r3 = mad_f32 r4 r0 r3
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r4 = mul_f32 r3 3D93DD98 (0.0722)
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r4 = mad_f32 r3 r2 r4
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r4 = mad_f32 r3 r1 r4
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r4 = mul_f32 r4 437F0000 (255)
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2019-11-08 20:18:06 +00:00
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r4 = round r4
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store8 arg(1) r4
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2019-06-03 21:27:46 +00:00
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|
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|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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G8 over RGBA_8888
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35 values:
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v0 = load8 arg(0)
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v1 = to_f32 v0
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v2 = mul_f32 v1 3B808081 (0.0039215689)
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v3 = load32 arg(1)
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↑ v4 = splat FF (3.5733111e-43)
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v5 = extract v3 0 v4
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v6 = to_f32 v5
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v7 = mul_f32 v6 3B808081 (0.0039215689)
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↑ v8 = splat 3F800000 (1)
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↑ v9 = sub_f32 v8 v8
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v10 = mad_f32 v7 v9 v2
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v11 = mul_f32 v10 437F0000 (255)
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v12 = round v11
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v13 = extract v3 8 v4
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v14 = to_f32 v13
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v15 = mul_f32 v14 3B808081 (0.0039215689)
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v16 = mad_f32 v15 v9 v2
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v17 = mul_f32 v16 437F0000 (255)
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2019-11-08 20:18:06 +00:00
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v18 = round v17
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sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
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v19 = pack v12 v18 8
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v20 = extract v3 16 v4
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v21 = to_f32 v20
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v22 = mul_f32 v21 3B808081 (0.0039215689)
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v23 = mad_f32 v22 v9 v2
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v24 = mul_f32 v23 437F0000 (255)
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v25 = round v24
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v26 = extract v3 24 v4
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v27 = to_f32 v26
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v28 = mul_f32 v27 3B808081 (0.0039215689)
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v29 = mad_f32 v28 v9 v8
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v30 = mul_f32 v29 437F0000 (255)
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v31 = round v30
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v32 = pack v25 v31 8
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v33 = pack v19 v32 16
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store32 arg(1) v33
|
2019-06-10 17:05:48 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
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|
7 registers, 35 instructions:
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|
r0 = splat FF (3.5733111e-43)
|
2019-06-05 15:47:46 +00:00
|
|
|
r1 = splat 3F800000 (1)
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r2 = sub_f32 r1 r1
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r3 = load8 arg(0)
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r4 = load32 arg(1)
|
|
|
|
r5 = extract r4 0 r0
|
2019-11-08 20:18:06 +00:00
|
|
|
r5 = to_f32 r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = mul_f32 r5 3B808081 (0.0039215689)
|
|
|
|
r5 = mad_f32 r5 r2 r3
|
|
|
|
r5 = mul_f32 r5 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r5 = round r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r6 = extract r4 8 r0
|
2019-11-08 20:18:06 +00:00
|
|
|
r6 = to_f32 r6
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r6 = mul_f32 r6 3B808081 (0.0039215689)
|
|
|
|
r6 = mad_f32 r6 r2 r3
|
|
|
|
r6 = mul_f32 r6 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r6 = round r6
|
|
|
|
r6 = pack r5 r6 8
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = extract r4 16 r0
|
|
|
|
r5 = to_f32 r5
|
|
|
|
r5 = mul_f32 r5 3B808081 (0.0039215689)
|
|
|
|
r3 = mad_f32 r5 r2 r3
|
|
|
|
r3 = mul_f32 r3 437F0000 (255)
|
|
|
|
r3 = round r3
|
|
|
|
r4 = extract r4 24 r0
|
|
|
|
r4 = to_f32 r4
|
|
|
|
r4 = mul_f32 r4 3B808081 (0.0039215689)
|
|
|
|
r4 = mad_f32 r4 r2 r1
|
|
|
|
r4 = mul_f32 r4 437F0000 (255)
|
|
|
|
r4 = round r4
|
|
|
|
r4 = pack r3 r4 8
|
|
|
|
r4 = pack r6 r4 16
|
|
|
|
store32 arg(1) r4
|
2019-06-03 21:27:46 +00:00
|
|
|
|
|
|
|
RGBA_8888 over A8
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
14 values:
|
|
|
|
v0 = load32 arg(0)
|
|
|
|
↑ v1 = splat FF (3.5733111e-43)
|
|
|
|
v2 = extract v0 24 v1
|
|
|
|
v3 = to_f32 v2
|
|
|
|
v4 = mul_f32 v3 3B808081 (0.0039215689)
|
|
|
|
v5 = load8 arg(1)
|
|
|
|
v6 = to_f32 v5
|
|
|
|
v7 = mul_f32 v6 3B808081 (0.0039215689)
|
|
|
|
↑ v8 = splat 3F800000 (1)
|
|
|
|
v9 = sub_f32 v8 v4
|
|
|
|
v10 = mad_f32 v7 v9 v4
|
|
|
|
v11 = mul_f32 v10 437F0000 (255)
|
|
|
|
v12 = round v11
|
|
|
|
store8 arg(1) v12
|
|
|
|
|
|
|
|
5 registers, 14 instructions:
|
|
|
|
r0 = splat FF (3.5733111e-43)
|
|
|
|
r1 = splat 3F800000 (1)
|
|
|
|
loop:
|
|
|
|
r2 = load32 arg(0)
|
|
|
|
r2 = extract r2 24 r0
|
|
|
|
r2 = to_f32 r2
|
|
|
|
r2 = mul_f32 r2 3B808081 (0.0039215689)
|
|
|
|
r3 = load8 arg(1)
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r4 = sub_f32 r1 r2
|
|
|
|
r2 = mad_f32 r3 r4 r2
|
|
|
|
r2 = mul_f32 r2 437F0000 (255)
|
|
|
|
r2 = round r2
|
|
|
|
store8 arg(1) r2
|
|
|
|
|
|
|
|
RGBA_8888 over G8
|
|
|
|
30 values:
|
|
|
|
v0 = load32 arg(0)
|
|
|
|
↑ v1 = splat FF (3.5733111e-43)
|
|
|
|
v2 = extract v0 0 v1
|
|
|
|
v3 = to_f32 v2
|
|
|
|
v4 = mul_f32 v3 3B808081 (0.0039215689)
|
|
|
|
v5 = load8 arg(1)
|
|
|
|
v6 = to_f32 v5
|
|
|
|
v7 = mul_f32 v6 3B808081 (0.0039215689)
|
|
|
|
v8 = extract v0 24 v1
|
|
|
|
v9 = to_f32 v8
|
|
|
|
v10 = mul_f32 v9 3B808081 (0.0039215689)
|
|
|
|
↑ v11 = splat 3F800000 (1)
|
|
|
|
v12 = sub_f32 v11 v10
|
|
|
|
v13 = mad_f32 v7 v12 v4
|
|
|
|
↑ v14 = splat 3E59B3D0 (0.21259999)
|
|
|
|
v15 = extract v0 8 v1
|
|
|
|
v16 = to_f32 v15
|
|
|
|
v17 = mul_f32 v16 3B808081 (0.0039215689)
|
|
|
|
v18 = mad_f32 v7 v12 v17
|
|
|
|
↑ v19 = splat 3F371759 (0.71520001)
|
|
|
|
v20 = extract v0 16 v1
|
|
|
|
v21 = to_f32 v20
|
|
|
|
v22 = mul_f32 v21 3B808081 (0.0039215689)
|
|
|
|
v23 = mad_f32 v7 v12 v22
|
|
|
|
v24 = mul_f32 v23 3D93DD98 (0.0722)
|
|
|
|
v25 = mad_f32 v18 v19 v24
|
|
|
|
v26 = mad_f32 v13 v14 v25
|
|
|
|
v27 = mul_f32 v26 437F0000 (255)
|
|
|
|
v28 = round v27
|
|
|
|
store8 arg(1) v28
|
2019-06-10 17:05:48 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
9 registers, 30 instructions:
|
|
|
|
r0 = splat FF (3.5733111e-43)
|
|
|
|
r1 = splat 3F800000 (1)
|
|
|
|
r2 = splat 3E59B3D0 (0.21259999)
|
|
|
|
r3 = splat 3F371759 (0.71520001)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
2019-11-08 20:18:06 +00:00
|
|
|
r4 = load32 arg(0)
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = extract r4 0 r0
|
2019-11-05 02:14:24 +00:00
|
|
|
r5 = to_f32 r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = mul_f32 r5 3B808081 (0.0039215689)
|
|
|
|
r6 = load8 arg(1)
|
|
|
|
r6 = to_f32 r6
|
|
|
|
r6 = mul_f32 r6 3B808081 (0.0039215689)
|
|
|
|
r7 = extract r4 24 r0
|
|
|
|
r7 = to_f32 r7
|
|
|
|
r7 = mul_f32 r7 3B808081 (0.0039215689)
|
|
|
|
r7 = sub_f32 r1 r7
|
|
|
|
r5 = mad_f32 r6 r7 r5
|
|
|
|
r8 = extract r4 8 r0
|
|
|
|
r8 = to_f32 r8
|
|
|
|
r8 = mul_f32 r8 3B808081 (0.0039215689)
|
|
|
|
r8 = mad_f32 r6 r7 r8
|
|
|
|
r4 = extract r4 16 r0
|
|
|
|
r4 = to_f32 r4
|
|
|
|
r4 = mul_f32 r4 3B808081 (0.0039215689)
|
|
|
|
r4 = mad_f32 r6 r7 r4
|
|
|
|
r4 = mul_f32 r4 3D93DD98 (0.0722)
|
|
|
|
r4 = mad_f32 r8 r3 r4
|
|
|
|
r4 = mad_f32 r5 r2 r4
|
|
|
|
r4 = mul_f32 r4 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r4 = round r4
|
|
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|
store8 arg(1) r4
|
2019-06-05 15:47:46 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
RGBA_8888 over RGBA_8888
|
|
|
|
45 values:
|
|
|
|
v0 = load32 arg(0)
|
|
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|
↑ v1 = splat FF (3.5733111e-43)
|
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v2 = extract v0 0 v1
|
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v3 = to_f32 v2
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v4 = mul_f32 v3 3B808081 (0.0039215689)
|
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v5 = load32 arg(1)
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v6 = extract v5 0 v1
|
2019-07-17 17:09:09 +00:00
|
|
|
v7 = to_f32 v6
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
v8 = mul_f32 v7 3B808081 (0.0039215689)
|
|
|
|
v9 = extract v0 24 v1
|
2019-07-17 17:09:09 +00:00
|
|
|
v10 = to_f32 v9
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
v11 = mul_f32 v10 3B808081 (0.0039215689)
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
↑ v12 = splat 3F800000 (1)
|
|
|
|
v13 = sub_f32 v12 v11
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
v14 = mad_f32 v8 v13 v4
|
|
|
|
v15 = mul_f32 v14 437F0000 (255)
|
|
|
|
v16 = round v15
|
|
|
|
v17 = extract v0 8 v1
|
|
|
|
v18 = to_f32 v17
|
|
|
|
v19 = mul_f32 v18 3B808081 (0.0039215689)
|
|
|
|
v20 = extract v5 8 v1
|
|
|
|
v21 = to_f32 v20
|
|
|
|
v22 = mul_f32 v21 3B808081 (0.0039215689)
|
|
|
|
v23 = mad_f32 v22 v13 v19
|
|
|
|
v24 = mul_f32 v23 437F0000 (255)
|
|
|
|
v25 = round v24
|
|
|
|
v26 = pack v16 v25 8
|
|
|
|
v27 = extract v0 16 v1
|
|
|
|
v28 = to_f32 v27
|
|
|
|
v29 = mul_f32 v28 3B808081 (0.0039215689)
|
|
|
|
v30 = extract v5 16 v1
|
|
|
|
v31 = to_f32 v30
|
|
|
|
v32 = mul_f32 v31 3B808081 (0.0039215689)
|
|
|
|
v33 = mad_f32 v32 v13 v29
|
|
|
|
v34 = mul_f32 v33 437F0000 (255)
|
|
|
|
v35 = round v34
|
|
|
|
v36 = extract v5 24 v1
|
|
|
|
v37 = to_f32 v36
|
|
|
|
v38 = mul_f32 v37 3B808081 (0.0039215689)
|
|
|
|
v39 = mad_f32 v38 v13 v11
|
|
|
|
v40 = mul_f32 v39 437F0000 (255)
|
|
|
|
v41 = round v40
|
|
|
|
v42 = pack v35 v41 8
|
|
|
|
v43 = pack v26 v42 16
|
|
|
|
store32 arg(1) v43
|
2019-06-10 17:05:48 +00:00
|
|
|
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
9 registers, 45 instructions:
|
|
|
|
r0 = splat FF (3.5733111e-43)
|
|
|
|
r1 = splat 3F800000 (1)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r2 = load32 arg(0)
|
|
|
|
r3 = extract r2 0 r0
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r4 = load32 arg(1)
|
|
|
|
r5 = extract r4 0 r0
|
2019-11-08 20:18:06 +00:00
|
|
|
r5 = to_f32 r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = mul_f32 r5 3B808081 (0.0039215689)
|
|
|
|
r6 = extract r2 24 r0
|
|
|
|
r6 = to_f32 r6
|
|
|
|
r6 = mul_f32 r6 3B808081 (0.0039215689)
|
|
|
|
r7 = sub_f32 r1 r6
|
|
|
|
r3 = mad_f32 r5 r7 r3
|
|
|
|
r3 = mul_f32 r3 437F0000 (255)
|
|
|
|
r3 = round r3
|
|
|
|
r5 = extract r2 8 r0
|
|
|
|
r5 = to_f32 r5
|
|
|
|
r5 = mul_f32 r5 3B808081 (0.0039215689)
|
|
|
|
r8 = extract r4 8 r0
|
2019-11-05 02:14:24 +00:00
|
|
|
r8 = to_f32 r8
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r8 = mul_f32 r8 3B808081 (0.0039215689)
|
|
|
|
r5 = mad_f32 r8 r7 r5
|
|
|
|
r5 = mul_f32 r5 437F0000 (255)
|
2019-11-08 20:18:06 +00:00
|
|
|
r5 = round r5
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r5 = pack r3 r5 8
|
|
|
|
r2 = extract r2 16 r0
|
|
|
|
r2 = to_f32 r2
|
|
|
|
r2 = mul_f32 r2 3B808081 (0.0039215689)
|
|
|
|
r3 = extract r4 16 r0
|
|
|
|
r3 = to_f32 r3
|
|
|
|
r3 = mul_f32 r3 3B808081 (0.0039215689)
|
|
|
|
r2 = mad_f32 r3 r7 r2
|
|
|
|
r2 = mul_f32 r2 437F0000 (255)
|
|
|
|
r2 = round r2
|
|
|
|
r4 = extract r4 24 r0
|
2019-11-08 20:18:06 +00:00
|
|
|
r4 = to_f32 r4
|
sketch out structure for ops with immediates
Lots of x86 instructions can take their right hand side argument from
memory directly rather than a register. We can use this to avoid the
need to allocate a register for many constants.
The strategy in this CL is one of several I've been stewing over, the
simplest of those strategies I think. There are some trade offs
particularly on ARM; this naive ARM implementation means we'll load&op
every time, even though the load part of the operation can logically be
hoisted. From here on I'm going to just briefly enumerate a few other
approaches that allow the optimization on x86 and still allow the
immediate splats to hoist on ARM.
1) don't do it on ARM
A very simple approach is to simply not perform this optimization on
ARM. ARM has more vector registers than x86, and so register pressure
is lower there. We're going to end up with splatted constants in
registers anyway, so maybe just let that happen the normal way instead
of some roundabout complicated hack like I'll talk about in 2). The
only downside in my mind is that this approach would make high-level
program descriptions platform dependent, which isn't so bad, but it's
been nice to be able to compare and diff debug dumps.
2) split Op::splat up
The next less-simple approach to this problem could fix this by
splitting splats into two Ops internally, one inner Op::immediate that
guantees at least the constant is in memory and is compatible with
immediate-aware Ops like mul_f32_imm, and an outer Op::constant that
depends on that Op::immediate and further guarantees that constant has
been broadcast into a register to be compatible with non-immediate-aware
ops like div_f32. When building a program, immediate-aware ops would
peek for Op::constants as they do today for Op::splats, but instead of
embedding the immediate themselves, they'd replace their dependency with
the inner Op::immediate.
On x86 these new Ops would work just as advertised, with Op::immediate a
runtime no-op, Op::constant the usual vbroadcastss. On ARM
Op::immediate needs to go all the way and splat out a register to make
the constant compatible with immediate-aware ops, and the Op::constant
becomes a noop now instead. All this comes together to let the
Op::immediate splat hoist up out of the loop while still feeding
Op::mul_f32_imm and co. It's a rather complicated approach to solving
this issue, but I might want to explore it just to see how bad it is.
3) do it inside the x86 JIT
The conceptually best approach is to find a way to do this peepholing
only inside the JIT only on x86, avoiding the need for new
Op::mul_f32_imm and co. ARM and the interpreter don't benefit from this
peephole, so the x86 JIT is the logical owner of this optimization.
Finding a clean way to do this without too much disruption is the least
baked idea I've got here, though I think the most desirable long-term.
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Debug-All-SK_USE_SKVM_BLITTER,Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SK_USE_SKVM_BLITTER
Change-Id: Ie9c6336ed08b6fbeb89acf920a48a319f74f3643
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254217
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-11-12 15:07:23 +00:00
|
|
|
r4 = mul_f32 r4 3B808081 (0.0039215689)
|
|
|
|
r6 = mad_f32 r4 r7 r6
|
|
|
|
r6 = mul_f32 r6 437F0000 (255)
|
|
|
|
r6 = round r6
|
|
|
|
r6 = pack r2 r6 8
|
|
|
|
r6 = pack r5 r6 16
|
|
|
|
store32 arg(1) r6
|
2019-06-05 15:47:46 +00:00
|
|
|
|
2019-06-20 16:37:10 +00:00
|
|
|
I32 (Naive) 8888 over 8888
|
2019-07-02 20:39:23 +00:00
|
|
|
29 values:
|
2019-07-17 17:09:09 +00:00
|
|
|
v0 = load32 arg(0)
|
2019-07-22 18:44:54 +00:00
|
|
|
↑ v1 = splat FF (3.5733111e-43)
|
2019-07-17 17:09:09 +00:00
|
|
|
v2 = extract v0 0 v1
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v3 = load32 arg(1)
|
|
|
|
v4 = extract v3 0 v1
|
2019-07-17 17:09:09 +00:00
|
|
|
v5 = extract v0 24 v1
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
↑ v6 = splat 100 (3.5873241e-43)
|
|
|
|
v7 = sub_i32 v6 v5
|
|
|
|
v8 = mul_i32 v4 v7
|
|
|
|
v9 = shr_i32 v8 8
|
|
|
|
v10 = add_i32 v2 v9
|
|
|
|
v11 = extract v0 8 v1
|
|
|
|
v12 = extract v3 8 v1
|
|
|
|
v13 = mul_i32 v12 v7
|
2019-07-25 19:32:19 +00:00
|
|
|
v14 = shr_i32 v13 8
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v15 = add_i32 v11 v14
|
|
|
|
v16 = pack v10 v15 8
|
|
|
|
v17 = extract v0 16 v1
|
|
|
|
v18 = extract v3 16 v1
|
|
|
|
v19 = mul_i32 v18 v7
|
2019-07-25 19:32:19 +00:00
|
|
|
v20 = shr_i32 v19 8
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v21 = add_i32 v17 v20
|
|
|
|
v22 = extract v3 24 v1
|
|
|
|
v23 = mul_i32 v22 v7
|
|
|
|
v24 = shr_i32 v23 8
|
|
|
|
v25 = add_i32 v5 v24
|
|
|
|
v26 = pack v21 v25 8
|
|
|
|
v27 = pack v16 v26 16
|
2019-07-17 17:09:09 +00:00
|
|
|
store32 arg(1) v27
|
2019-07-02 20:39:23 +00:00
|
|
|
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
9 registers, 29 instructions:
|
2019-06-20 16:37:10 +00:00
|
|
|
r0 = splat FF (3.5733111e-43)
|
|
|
|
r1 = splat 100 (3.5873241e-43)
|
|
|
|
loop:
|
2019-11-05 02:14:24 +00:00
|
|
|
r2 = load32 arg(0)
|
|
|
|
r3 = extract r2 0 r0
|
|
|
|
r4 = load32 arg(1)
|
|
|
|
r5 = extract r4 0 r0
|
|
|
|
r6 = extract r2 24 r0
|
|
|
|
r7 = sub_i32 r1 r6
|
|
|
|
r5 = mul_i32 r5 r7
|
|
|
|
r5 = shr_i32 r5 8
|
|
|
|
r5 = add_i32 r3 r5
|
|
|
|
r3 = extract r2 8 r0
|
|
|
|
r8 = extract r4 8 r0
|
|
|
|
r8 = mul_i32 r8 r7
|
|
|
|
r8 = shr_i32 r8 8
|
|
|
|
r8 = add_i32 r3 r8
|
|
|
|
r8 = pack r5 r8 8
|
|
|
|
r2 = extract r2 16 r0
|
|
|
|
r5 = extract r4 16 r0
|
|
|
|
r5 = mul_i32 r5 r7
|
|
|
|
r5 = shr_i32 r5 8
|
|
|
|
r5 = add_i32 r2 r5
|
|
|
|
r4 = extract r4 24 r0
|
|
|
|
r7 = mul_i32 r4 r7
|
|
|
|
r7 = shr_i32 r7 8
|
|
|
|
r7 = add_i32 r6 r7
|
|
|
|
r7 = pack r5 r7 8
|
|
|
|
r7 = pack r8 r7 16
|
|
|
|
store32 arg(1) r7
|
2019-06-20 16:37:10 +00:00
|
|
|
|
2019-06-05 15:47:46 +00:00
|
|
|
I32 8888 over 8888
|
2019-07-02 20:39:23 +00:00
|
|
|
29 values:
|
2019-07-17 17:09:09 +00:00
|
|
|
v0 = load32 arg(0)
|
2019-07-22 18:44:54 +00:00
|
|
|
↑ v1 = splat FF (3.5733111e-43)
|
2019-07-17 17:09:09 +00:00
|
|
|
v2 = bit_and v0 v1
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v3 = load32 arg(1)
|
|
|
|
v4 = bit_and v3 v1
|
2019-07-25 19:32:19 +00:00
|
|
|
v5 = shr_i32 v0 24
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
↑ v6 = splat 100 (3.5873241e-43)
|
|
|
|
v7 = sub_i32 v6 v5
|
|
|
|
v8 = mul_i16x2 v4 v7
|
|
|
|
v9 = shr_i32 v8 8
|
|
|
|
v10 = add_i32 v2 v9
|
|
|
|
v11 = bytes v0 2
|
|
|
|
v12 = bytes v3 2
|
|
|
|
v13 = mul_i16x2 v12 v7
|
2019-07-25 19:32:19 +00:00
|
|
|
v14 = shr_i32 v13 8
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v15 = add_i32 v11 v14
|
|
|
|
v16 = pack v10 v15 8
|
|
|
|
v17 = bytes v0 3
|
|
|
|
v18 = bytes v3 3
|
|
|
|
v19 = mul_i16x2 v18 v7
|
2019-07-25 19:32:19 +00:00
|
|
|
v20 = shr_i32 v19 8
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v21 = add_i32 v17 v20
|
|
|
|
v22 = shr_i32 v3 24
|
|
|
|
v23 = mul_i16x2 v22 v7
|
|
|
|
v24 = shr_i32 v23 8
|
|
|
|
v25 = add_i32 v5 v24
|
|
|
|
v26 = pack v21 v25 8
|
|
|
|
v27 = pack v16 v26 16
|
2019-07-17 17:09:09 +00:00
|
|
|
store32 arg(1) v27
|
2019-07-02 20:39:23 +00:00
|
|
|
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
9 registers, 29 instructions:
|
2019-06-05 15:47:46 +00:00
|
|
|
r0 = splat FF (3.5733111e-43)
|
2019-06-13 15:56:51 +00:00
|
|
|
r1 = splat 100 (3.5873241e-43)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
2019-11-05 02:14:24 +00:00
|
|
|
r2 = load32 arg(0)
|
|
|
|
r3 = bit_and r2 r0
|
|
|
|
r4 = load32 arg(1)
|
|
|
|
r5 = bit_and r4 r0
|
|
|
|
r6 = shr_i32 r2 24
|
|
|
|
r7 = sub_i32 r1 r6
|
|
|
|
r5 = mul_i16x2 r5 r7
|
|
|
|
r5 = shr_i32 r5 8
|
|
|
|
r5 = add_i32 r3 r5
|
|
|
|
r3 = bytes r2 2
|
|
|
|
r8 = bytes r4 2
|
|
|
|
r8 = mul_i16x2 r8 r7
|
|
|
|
r8 = shr_i32 r8 8
|
|
|
|
r8 = add_i32 r3 r8
|
|
|
|
r8 = pack r5 r8 8
|
|
|
|
r2 = bytes r2 3
|
|
|
|
r5 = bytes r4 3
|
|
|
|
r5 = mul_i16x2 r5 r7
|
|
|
|
r5 = shr_i32 r5 8
|
|
|
|
r5 = add_i32 r2 r5
|
|
|
|
r4 = shr_i32 r4 24
|
|
|
|
r7 = mul_i16x2 r4 r7
|
|
|
|
r7 = shr_i32 r7 8
|
|
|
|
r7 = add_i32 r6 r7
|
|
|
|
r7 = pack r5 r7 8
|
|
|
|
r7 = pack r8 r7 16
|
|
|
|
store32 arg(1) r7
|
2019-06-03 22:10:59 +00:00
|
|
|
|
|
|
|
I32 (SWAR) 8888 over 8888
|
2019-07-02 20:39:23 +00:00
|
|
|
15 values:
|
2019-07-17 17:09:09 +00:00
|
|
|
v0 = load32 arg(0)
|
|
|
|
v1 = bytes v0 404
|
2019-07-22 18:44:54 +00:00
|
|
|
↑ v2 = splat 1000100 (2.3510604e-38)
|
2019-07-17 17:09:09 +00:00
|
|
|
v3 = sub_i16x2 v2 v1
|
|
|
|
v4 = load32 arg(1)
|
2019-07-22 18:44:54 +00:00
|
|
|
↑ v5 = splat FF00FF (2.3418409e-38)
|
2019-07-17 17:09:09 +00:00
|
|
|
v6 = bit_and v4 v5
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v7 = mul_i16x2 v6 v3
|
|
|
|
v8 = shr_i16x2 v7 8
|
|
|
|
v9 = shr_i16x2 v4 8
|
|
|
|
v10 = mul_i16x2 v9 v3
|
2019-07-17 17:09:09 +00:00
|
|
|
v11 = bit_clear v10 v5
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
v12 = bit_or v8 v11
|
2019-07-17 17:09:09 +00:00
|
|
|
v13 = add_i32 v0 v12
|
|
|
|
store32 arg(1) v13
|
2019-07-02 20:39:23 +00:00
|
|
|
|
2019-06-24 00:35:28 +00:00
|
|
|
6 registers, 15 instructions:
|
2019-06-13 18:12:38 +00:00
|
|
|
r0 = splat 1000100 (2.3510604e-38)
|
|
|
|
r1 = splat FF00FF (2.3418409e-38)
|
2019-06-05 15:47:46 +00:00
|
|
|
loop:
|
2019-11-05 02:14:24 +00:00
|
|
|
r2 = load32 arg(0)
|
|
|
|
r3 = bytes r2 404
|
|
|
|
r3 = sub_i16x2 r0 r3
|
|
|
|
r4 = load32 arg(1)
|
|
|
|
r5 = bit_and r4 r1
|
|
|
|
r5 = mul_i16x2 r5 r3
|
|
|
|
r5 = shr_i16x2 r5 8
|
|
|
|
r4 = shr_i16x2 r4 8
|
|
|
|
r3 = mul_i16x2 r4 r3
|
|
|
|
r3 = bit_clear r3 r1
|
|
|
|
r3 = bit_or r5 r3
|
|
|
|
r3 = add_i32 r2 r3
|
|
|
|
store32 arg(1) r3
|
2019-06-03 22:10:59 +00:00
|
|
|
|
2019-08-08 19:13:25 +00:00
|
|
|
6 values:
|
2019-10-16 15:46:01 +00:00
|
|
|
↟ v0 = splat 1 (1.4012985e-45)
|
|
|
|
↟ v1 = splat 2 (2.8025969e-45)
|
2019-08-08 19:13:25 +00:00
|
|
|
↑ v2 = add_i32 v0 v1
|
|
|
|
v3 = load32 arg(0)
|
|
|
|
v4 = mul_i32 v3 v2
|
|
|
|
store32 arg(0) v4
|
|
|
|
|
|
|
|
2 registers, 6 instructions:
|
|
|
|
r0 = splat 1 (1.4012985e-45)
|
|
|
|
r1 = splat 2 (2.8025969e-45)
|
|
|
|
r1 = add_i32 r0 r1
|
|
|
|
loop:
|
2019-11-05 02:14:24 +00:00
|
|
|
r0 = load32 arg(0)
|
|
|
|
r0 = mul_i32 r0 r1
|
|
|
|
store32 arg(0) r0
|
2019-08-08 19:13:25 +00:00
|
|
|
|
reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
|
|
|
19 values:
|
|
|
|
↑ v0 = splat FF (3.5733111e-43)
|
|
|
|
v1 = load32 arg(0)
|
|
|
|
v2 = extract v1 0 v0
|
|
|
|
v3 = load32 arg(1)
|
|
|
|
v4 = extract v3 0 v0
|
|
|
|
v5 = add_i32 v2 v4
|
|
|
|
v6 = extract v1 8 v0
|
|
|
|
v7 = extract v3 8 v0
|
|
|
|
v8 = add_i32 v6 v7
|
|
|
|
v9 = pack v5 v8 8
|
|
|
|
v10 = extract v1 16 v0
|
|
|
|
v11 = extract v3 16 v0
|
|
|
|
v12 = add_i32 v10 v11
|
|
|
|
v13 = extract v1 24 v0
|
|
|
|
v14 = extract v3 24 v0
|
|
|
|
v15 = add_i32 v13 v14
|
|
|
|
v16 = pack v12 v15 8
|
|
|
|
v17 = pack v9 v16 16
|
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store32 arg(1) v17
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6 registers, 19 instructions:
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r0 = splat FF (3.5733111e-43)
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loop:
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2019-11-05 02:14:24 +00:00
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r1 = load32 arg(0)
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r2 = extract r1 0 r0
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r3 = load32 arg(1)
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r4 = extract r3 0 r0
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r4 = add_i32 r2 r4
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r2 = extract r1 8 r0
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r5 = extract r3 8 r0
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r5 = add_i32 r2 r5
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r5 = pack r4 r5 8
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r4 = extract r1 16 r0
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r2 = extract r3 16 r0
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r2 = add_i32 r4 r2
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r1 = extract r1 24 r0
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r3 = extract r3 24 r0
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r3 = add_i32 r1 r3
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r3 = pack r2 r3 8
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r3 = pack r5 r3 16
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store32 arg(1) r3
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reorder to minimize register pressure
Rewrite program instructions so that each value becomes available as
late as possible, just before it's used by another instruction. This
reorders blocks of instructions to reduce them number of temporary
registers in flight.
Take this example of the sort of program that we naturally write,
noting the registers needed as we progress down the right:
src = load32 ... (1)
sr = extract src ... (2)
sg = extract src ... (3)
sb = extract src ... (4)
sa = extract src ... (4, src dies)
dst = load32 ... (5)
dr = extract dst ... (6)
dg = extract dst ... (7)
db = extract dst ... (8)
da = extract dst ... (8, dst dies)
r = add sr dr (7, sr and dr die)
g = add sg dg (6, sg and dg die)
b = add sb db (5, sb and db die)
a = add sa da (4, sa and da die)
rg = pack r g ... (3, r and g die)
ba = pack b a ... (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0, rgba dies)
That original ordering of the code needs 8 registers (perhaps with a
temporary 9th, but we'll ignore that here). This CL will rewrite the
program to something more like this by recursively issuing inputs only
once needed:
src = load32 ... (1)
sr = extract src ... (2)
dst = load32 ... (3)
dr = extract dst ... (4)
r = add sr dr (3, sr and dr die)
sg = extract src ... (4)
dg = extract dst ... (5)
g = add sg dg (4, sg and dg die)
rg = pack r g (3, r and g die)
sb = extract src ... (4)
db = extract dst ... (5)
b = add sb db (4, sb and db die)
sa = extract src ... (4, src dies)
da = extract dst ... (4, dst dies)
a = add sa da (3, sa and da die)
ba = pack b a (2, b and a die)
rgba = pack rg ba ... (1, rg and ba die)
store32 rgba ... (0)
That trims 3 registers off the example, just by reordering!
I've added the real version of this example to SkVMTest.cpp.
(Its 6th register comes from holding the 0xff byte mask used
by extract, in case you're curious).
I'll admit it's not exactly easy to work out how this reordering works
without a pen and paper or trial and error. I've tried to make the
implementation preserve the original program's order as much as makes
sense (i.e. when order is an otherwise arbitrary choice) to keep it
somewhat sane to follow.
This reordering naturally skips dead code, so pour one out for ☠️ .
We lose our cute dead code emoji marker, but on the other hand all code
downstream of Builder::done() can assume every instruction is live.
Change-Id: Iceffcd10fd7465eae51a39ef8eec7a7189766ba2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249999
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2019-10-22 17:27:58 +00:00
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