Make TryEmitCbzOrTbz a template, so it can be used for Word64 as well as Word32.
0.09% reduction of embedded builtins size with a arm64 ptr-compr build.
Some of the unittests weren't ported to Word64 as they don't pass, this is due to
VisitWordCompare missing a loop to remove Word64Equal comparisons against 0. This
can be added in a different CL if needed.
Change-Id: I927129d934083b71abe5b77991c39286470a228d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1792908
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63751}
This removes LoadStackPointer and its last remaining use in the
interpreter assembler.
Bug: v8:9534
Change-Id: I19aafb12c5fd50248841a3d92448e64243c723ad
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1748729
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63164}
With compressed pointers, `kArchStoreWithBarrier` is a 32-bit store instead of
64-bit, and this means the index has a differerent immediate range.
Bug: v8:7703
Change-Id: If61c8544b0da87ba2779ba2c1a6963b52e3e5d9a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1710674
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62861}
With a write barrier, stores with negative offsets would allocate a temporary
register to hold the offset when the `str` instruction is able to encode it.
For instance, when writing the object map:
```
;; This could be 'str x2, [x5, #-1]'
movn x4, #0x0
str x2, [x5, x4]
and x16, x5, #0xfffffffffffc0000
ldr x16, [x16, #8]
tbnz w16, #2, #+0xba8 ; Jump out-of-line
```
The reason behind this is that the out-of-line code uses an 'add' instruction on
the offset to compute the field address, putting pressure on the instruction
selector to make sure the immediate fits in both 'str' and 'add'.
But, this is not necessary since the macro-assembler is able to turn the 'add'
into a 'sub' or use a temporary register if needed.
Change-Id: I8838e4b81a0c0c1f90aa3d67861a9da1a6dfed06
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1708471
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#62803}
Cpplint usually checks for non-const reference arguments. They are
forbidden in the style guide, and v8 does not explicitly make an
exception here.
This CL re-enables that warning, and fixes all current violations by
adding an explicit "NOLINT(runtime/references)" comment. In follow-up
CLs, we should aim to remove as many of them as possible.
TBR=mlippautz@chromium.org
Bug: v8:9429
Change-Id: If7054d0b366138b731972ed5d4e304b5ac8423bb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687891
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62551}
On Windows, long is 32-bits, so the 'L' suffix shouldn't be used if a
64-bit value is needed. This caused a test failure in 'Int64MulWithImmediate'.
Change-Id: I93c43a1f166aa0e5bcd53aaf7a860fffd006fd0b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1627538
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61986}
This replaces all typedefs that define types and not functions by the
equivalent "using" declaration.
This was done mostly automatically using this command:
ag -l '\btypedef\b' src test | xargs -L1 \
perl -i -p0e 's/typedef ([^*;{}]+) (\w+);/using \2 = \1;/sg'
Patchset 2 then adds some manual changes for typedefs for pointer types,
where the regular expression did not match.
R=mstarzinger@chromium.orgTBR=yangguo@chromium.org, jarin@chromium.org
Bug: v8:9183
Change-Id: I6f6ee28d1793b7ac34a58f980b94babc21874b78
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1631409
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61849}
This also fixes a bug in 'InitializeCallBuffer', where it wouldn't claim enough
slots for each parameter. This caused the Simd128 instruction selector test to
only claim 3 slots (rather than 4) and then perform an unnecessary padding poke.
v8_Default_embedded_blob_size from the generated file gen/embedded.S
Before: 4957056
After: 4954368
This gives a 0.05% size decrease.
Change-Id: Ic9bb998fb8a9111fb90e1c3e537ea0f2a5fa7b33
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1617665
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Cr-Commit-Position: refs/heads/master@{#61649}
FNMUL is efficient arm64 instruction, which can save 1 cycle
by optimizing FNEG(FMUL x y)) to FNMUL x y and
FMUL((FNEG x) y) to FNMUL x y
Change-Id: If25d9de1253098b17033a9d8736ff6a1c06601f3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1572681
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Martyn Capewell <martyn.capewell@arm.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61230}
Googletest is (at last) converging with industry-standard terminology
[1]. We previously called test suites "test cases", which was rather
confusing for folks coming from any other testing framework.
Chrome now has a googletest version that supports _TEST_SUITE_ macros
instead of _TEST_CASE_, so this CL cleans up some of the outdated usage.
[1] https://github.com/google/googletest/blob/master/googletest/docs/primer.md#beware-of-the-nomenclature
Bug: chromium:925652
Change-Id: I3cd02b9fa6dbece1594bbfd50a21ad7503c2aab9
Reviewed-on: https://chromium-review.googlesource.com/c/1475654
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59666}
This CL splits the backend of TurboFan off into its own directory,
without changing namespaces. This makes ownership management a bit
more fine-grained with a logical separation.
R=mstarzinger@chromium.org,jarin@chromium.org,adamk@chromium.org
Change-Id: I2ac40d6ca2c4f04b8474b630aae0286ecf79ef42
Reviewed-on: https://chromium-review.googlesource.com/c/1308333
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57437}
This is a reland of fcbb023b0e
Original change's description:
> Add Windows ARM64 ABI support to V8
>
> This change added Windows ARM64 ABI support, major things are:
> 1. Excluding x18 register from any usage because it is reserved as
> platform register. Preserve alignment after the change.
> 2. Fix the assumption of LP64 in arm64 backend. Windows ARM64 is
> still LLP64.
> 3. Stack guard page probe for large allocation on stack.
>
> Reference:
> Windows ARM64 ABI:
> https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=vs-2017
>
> Bug: chromium:893460
> Change-Id: I325884ac8dab719154a0047141e18a9fcb8dff7e
> Reviewed-on: https://chromium-review.googlesource.com/c/1285129
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#56881}
CQ_INCLUDE_TRYBOTS=luci.chromium.try:android_arm64_dbg_recipe
TBR=mlippautz@chromium.org
Bug: chromium:893460
Change-Id: Icc45fd091c33f7df805842a70236b79b14756f52
Reviewed-on: https://chromium-review.googlesource.com/c/1297300
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56965}
This reverts commit fcbb023b0e.
Reason for revert: blocks roll https://chromium-review.googlesource.com/c/chromium/src/+/1296315
Original change's description:
> Add Windows ARM64 ABI support to V8
>
> This change added Windows ARM64 ABI support, major things are:
> 1. Excluding x18 register from any usage because it is reserved as
> platform register. Preserve alignment after the change.
> 2. Fix the assumption of LP64 in arm64 backend. Windows ARM64 is
> still LLP64.
> 3. Stack guard page probe for large allocation on stack.
>
> Reference:
> Windows ARM64 ABI:
> https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=vs-2017
>
> Bug: chromium:893460
> Change-Id: I325884ac8dab719154a0047141e18a9fcb8dff7e
> Reviewed-on: https://chromium-review.googlesource.com/c/1285129
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#56881}
TBR=bbudge@chromium.org,ulan@chromium.org,machenbach@chromium.org,hpayer@chromium.org,brucedawson@chromium.org,mlippautz@chromium.org,ahaas@chromium.org,bmeurer@chromium.org,Tom.Tan@microsoft.com
Change-Id: I0b804af6dfca9409a655194fa6e5407f209be2dc
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:893460
Reviewed-on: https://chromium-review.googlesource.com/c/1296460
Reviewed-by: Michael Hablich <hablich@chromium.org>
Commit-Queue: Michael Hablich <hablich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56912}
This change added Windows ARM64 ABI support, major things are:
1. Excluding x18 register from any usage because it is reserved as
platform register. Preserve alignment after the change.
2. Fix the assumption of LP64 in arm64 backend. Windows ARM64 is
still LLP64.
3. Stack guard page probe for large allocation on stack.
Reference:
Windows ARM64 ABI:
https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=vs-2017
Bug: chromium:893460
Change-Id: I325884ac8dab719154a0047141e18a9fcb8dff7e
Reviewed-on: https://chromium-review.googlesource.com/c/1285129
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56881}
... containing RootsTable, ExternalReferenceTable, builtins array and
potentially some other data that can be accessed via the RootRegister.
This is a preliminary step before adding support for pointer-compression
friendly heap layout.
Bug: v8:8182
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I2899f657aaff1351a5304afa0b1a4c5ae4cfc31d
Reviewed-on: https://chromium-review.googlesource.com/c/1245426
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56551}
This is useful even if there are other uses of the
arithmetic result, because it moves dependencies further back.
Change-Id: I6136a657b547198cb4ec92f38b89ddf5df334124
Reviewed-on: https://chromium-review.googlesource.com/1179662
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Bogdan Lazarescu <bogdan.lazarescu@arm.com>
Cr-Commit-Position: refs/heads/master@{#55292}
This should make the uses of binary vs. bitwise not very clear:
- Word32BinaryNot for logical negation
- Word32BitwiseNot for bitwise negation
Change-Id: I3345913111da0dbdae6fdf285f090b67eb3f3afc
Reviewed-on: https://chromium-review.googlesource.com/1169205
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55091}
When encountering a LoadStackPointer input to a comparison, generate a register
LocationOperand that points to the stack pointer. This can avoid unnecessary
spilling of the stack pointer.
Since sp is a special register for arm64, we need to add a mechanism to print
its name in RegisterConfiguration.
This is a port of https://chromium-review.googlesource.com/1055568 that made
the same change for arm.
It also ports the tests added in
https://chromium-review.googlesource.com/1099068 to arm and arm64.
Bug: v8:7844
Change-Id: I5adc672ff877b9888ef755e8e60e4eabbc61061b
Reviewed-on: https://chromium-review.googlesource.com/1107810
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Cr-Commit-Position: refs/heads/master@{#53889}
Add support for matching '(x & mask) == mask' when mask has a single bit set,
and translate this into a tbnz instruction. This patch only does this for 32-bit
operations, we can port it to 64-bit operations as a follow-up if we find
matches.
This transformation mostly touches the snapshot where we get ~120 hits. This pattern can
also show up in JavaScript when introduced by the EffectControlLinearizer pass.
Bug:
Change-Id: Ib37c6e0bd3831b7c17709357b00ca53735621605
Reviewed-on: https://chromium-review.googlesource.com/803272
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#49822}
This patch normalizes the casing of hexadecimal digits in escape
sequences of the form `\xNN` and integer literals of the form
`0xNNNN`.
Previously, the V8 code base used an inconsistent mixture of uppercase
and lowercase.
Google’s C++ style guide uses uppercase in its examples:
https://google.github.io/styleguide/cppguide.html#Non-ASCII_Characters
Moreover, uppercase letters more clearly stand out from the lowercase
`x` (or `u`) characters at the start, as well as lowercase letters
elsewhere in strings.
BUG=v8:7109
TBR=marja@chromium.org,titzer@chromium.org,mtrofin@chromium.org,mstarzinger@chromium.org,rossberg@chromium.org,yangguo@chromium.org,mlippautz@chromium.org
NOPRESUBMIT=true
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I790e21c25d96ad5d95c8229724eb45d2aa9e22d6
Reviewed-on: https://chromium-review.googlesource.com/804294
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49810}
V8_INT64_C will be cleaned up in a follow-up CL.
R=tebbi@chromium.org,mlippautz@chromium.org
Bug: v8:7109
Change-Id: I6af97e7266039eb443896b404b77b8e2b5de5adb
Reviewed-on: https://chromium-review.googlesource.com/803294
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49790}
This makes the function constexpr and implements it for arbitrary
unsigned integer types (up to 64 bits, but this can be extended if
needed).
R=mstarzinger@chromium.org
Bug: v8:6600, v8:6921
Change-Id: I86d427238fadd55abb5a27f31ed648d4b02fc358
Reviewed-on: https://chromium-review.googlesource.com/718457
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48696}
Arm64 compiles "x +_64 (y >> shift)" into a single instruction if
"shift" is a constant. The code generator expects that "shift" is a
32 bit constant. however, TurboFan can also pass in a 64 bit constant,
which caused a crash in the code generator.
With this CL we cast the constant of TurboFan to an int in the
instruction selector and thereby satisfy the assumption of the code
generator. This should be correct since the code generator anyways cast
the "shift" to an int5 or int6 eventually.
R=v8-arm-ports@googlegroups.com
BUG=v8:5923
Review-Url: https://codereview.chromium.org/2669203005
Cr-Commit-Position: refs/heads/master@{#43036}
Generate TBZ/TBNZ for certain comparisons against zero. E.g. instead of:
cmp w0, 0x0
b.lt/ge <addr>
we can generate:
tbnz/tbz w0, 31, <addr>
BUG=
Review-Url: https://codereview.chromium.org/2359723004
Cr-Commit-Position: refs/heads/master@{#39620}
We were previously incorrectly changing:
sub r0, 0, r1
cmp r2, r0
b.cond <addr>
to:
cmn r2, r1
b.cond <addr>
for all conditions. This is incorrect for conditions involving the C (carry)
and V (overflow) flags, and in particular in the case where r1 = INT_MIN.
The optimization is still safe to perform for Equal and NotEqual since they
do not depend on the C and V flags.
BUG=
Review-Url: https://codereview.chromium.org/2318043002
Cr-Commit-Position: refs/heads/master@{#39246}
This CL changes the semantics of FloatXXSub to match the semantics of
the semantics of FloatXXSubPreserveNan. Therefore there is no need
anymore for the FloatXXSubPreserveNan operators.
The optimizations in VisitFloatXXSub which are removed in this CL have
already been moved to machine-operator-reducer.cc in
https://codereview.chromium.org/2226663002R=bmeurer@chromium.org
Review-Url: https://codereview.chromium.org/2220973002
Cr-Commit-Position: refs/heads/master@{#38437}
Adding new methods to the code stub assembler and interpreter
assembler to combine loading and untagging SMIs, so that on 64-bit
architectures we can avoid loading the full 64 bits and load the
32 interesting bits directly instead.
Review-Url: https://codereview.chromium.org/2183923003
Cr-Commit-Position: refs/heads/master@{#38361}
So far we don't have a useful way to inline Math.max or Math.min in
TurboFan optimized code. This adds new operators NumberMax and NumberMin
and changes the Float64Max/Float64Min operators to have JavaScript
semantics instead of the C++ semantics that it had previously.
This also removes support for recognizing the tenary case in the
CommonOperatorReducer, since that doesn't seem to have any positive
impact (and actually doesn't show up in regular JavaScript, where
people use Math.max/Math.min instead).
Drive-by-fix: Also nuke the unused Float32Max/Float32Min operators.
R=jarin@chromium.org
Review-Url: https://codereview.chromium.org/2170343002
Cr-Commit-Position: refs/heads/master@{#37971}
Perform the following transformation:
| Before | After |
|------------------+---------------------|
| add w2, w0, w1 | adds w2, w0, w1 |
| cmp w2, #0x0 | b.<cond'> <addr> |
| b.<cond> <addr> | |
|------------------+---------------------|
| add w2, w0, w1 | adds w2, w0, w1 |
| cmp #0x0, w2 | b.<cond'> <addr> |
| b.<cond> <addr> | |
and the same for and instructions instead of add. When the result of the
add/and is not used, generate cmn/tst instead. We need to take care with which
conditions we can handle and what new condition we map them to.
BUG=
Review-Url: https://codereview.chromium.org/2065243005
Cr-Commit-Position: refs/heads/master@{#37400}
CMN is a flag-setting add operation, and therefore is commutative.
{Add,Sub}WithOverflow generate ADD/SUB instructions that cannot
support a ROR shift.
BUG=
Review-Url: https://codereview.chromium.org/2087233005
Cr-Commit-Position: refs/heads/master@{#37212}
This patch enables the following transformations in the instruction
selector:
| Before | After |
|------------------+------------------------|
| and x3, x1, #0x1 | tb{,n}z w1, #0, #+0x78 |
| cmp x3, #0x0 | |
| b.{eq,ne} #+0x80 | |
|------------------+------------------------|
| cmp x0, #0x0 | cb{,n}z x0, #+0x48 |
| b.{eq,ne} #+0x4c | |
I have not seen these patterns beeing generated by turbofan, however the
stubs hit these cases frequently. A particular reason is that we are
turning operations that check for a Smi into a single `tbz`.
As a concequence, the interpreter is affected thanks to inlining
turbofan stubs into it's bytecode handlers. I have noticed the size of
the interpreter was reduced by 200 instructions.
BUG=
Review-Url: https://codereview.chromium.org/2022073002
Cr-Commit-Position: refs/heads/master@{#36632}
Adding optional operators for FNeg for WebAssembly, as the current implementation was significantly suboptimal for ARM.
Review-Url: https://codereview.chromium.org/2011303002
Cr-Commit-Position: refs/heads/master@{#36544}
This patch adds support for the `Operand2_R_LSL_I` addressing mode to
loads and stores. This allows merging a shift instruction into a
MemoryOperand. Since the shift immediate is restricted to the log2 of
the operation width, the opportunities to hit this are slim. However,
Ignition's bytecode handlers hit this case all the time:
kind = BYTECODE_HANDLER
name = Star
compiler = turbofan
Instructions (size = 44)
0x23e67280 0 add x1, x19, #0x1 (1)
0x23e67284 4 ldrsb x1, [x20, x1]
0x23e67288 8 sxtw x1, w1
0x23e6728c 12 mov x2, fp
0x23e67290 16 str x0, [x2, x1, lsl #3]
^^^^^^^^^^^^^^^^^^^^^
0x23e67294 20 add x19, x19, #0x2 (2)
0x23e67298 24 ldrb w1, [x20, x19]
0x23e6729c 28 ldr x1, [x21, x1, lsl #3]
^^^^^^^^^^^^^^^^^^^^^
0x23e672a0 32 br x1
Additionally, I noticed the optimisation occurs once in both the
`StringPrototypeCharAt` and `StringPrototypeCharCodeAt` turbofan stubs.
BUG=
Review-Url: https://codereview.chromium.org/1972103002
Cr-Commit-Position: refs/heads/master@{#36227}
A load instruction will implicitely clear the top 32 bits when writing to a W
register. This patch avoids generating a `mov` instruction to zero-extend the
result in this case.
For example, this occurs in the generated code for dispatching to the next
bytecode in the interpreter:
kind = BYTECODE_HANDLER
name = LdaZero
compiler = turbofan
Instructions (size = 36)
0x32e64c60 0 add x19, x19, #0x1 (1)
0x32e64c64 4 ldrb w0, [x20, x19]
0x32e64c68 8 mov w0, w0
^^^^^^^^^^
0x32e64c6c 12 lsl x0, x0, #3
0x32e64c70 16 ldr x1, [x21, x0]
0x32e64c74 20 movz x0, #0x0
0x32e64c78 24 br x1
BUG=
Review-Url: https://codereview.chromium.org/1950013003
Cr-Commit-Position: refs/heads/master@{#36038}
When storing an immediate integer or floating point zero, use the zero register
as the source value. This avoids the need to sometimes allocate a new register.
BUG=
Review-Url: https://codereview.chromium.org/1945783002
Cr-Commit-Position: refs/heads/master@{#36013}
