skia2/tests/sksl/workarounds/RewriteMatrixVectorMultiply.asm.frag
John Stiles ffc9dec755 Eliminate redundant loads following stores.
We now have two functions `writeOpLoad` and `writeOpStore` which are
in charge of writing SpvOpLoad and SpvOpStore instructions.
`writeOpStore` also keeps track of pointer stores in a "store cache."
Subsequent loads from that same pointer will be found in the cache and
will return the value stored in that pointer instead.

Such a cache definitely cannot work in the face of control flow, so we
make the following concessions:
- `pruneReachableOps` is now `pruneConditionalOps`. Any pointers that
  are altered inside a potentially-unreachable block are cleared from
  the cache entirely.
- The entire store cache is cleared at all OpLabels within a loop.

The cache also cannot work in the presence of swizzled stores, so we
make another significant concession:
- The entire store cache is cleared whenever we store into a non-memory
  pointer (e.g., assigning into a swizzled LValue, such as `foo.xz`).

Despite these significant limitations, this manages to dramatically
shrink many real-world examples.

Change-Id: I0981a0cf7b45b064e153e9ada271494c8e00cad5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/530054
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
2022-04-18 14:57:48 +00:00

87 lines
3.1 KiB
JavaScript

OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %_entrypoint_v "_entrypoint" %sk_FragColor %sk_Clockwise
OpExecutionMode %_entrypoint_v OriginUpperLeft
OpName %sk_FragColor "sk_FragColor"
OpName %sk_Clockwise "sk_Clockwise"
OpName %_entrypoint_v "_entrypoint_v"
OpName %main "main"
OpName %m44 "m44"
OpName %v4 "v4"
OpDecorate %sk_FragColor RelaxedPrecision
OpDecorate %sk_FragColor Location 0
OpDecorate %sk_FragColor Index 0
OpDecorate %sk_Clockwise BuiltIn FrontFacing
OpDecorate %m44 RelaxedPrecision
OpDecorate %v4 RelaxedPrecision
OpDecorate %36 RelaxedPrecision
OpDecorate %37 RelaxedPrecision
OpDecorate %40 RelaxedPrecision
OpDecorate %41 RelaxedPrecision
OpDecorate %42 RelaxedPrecision
OpDecorate %45 RelaxedPrecision
OpDecorate %46 RelaxedPrecision
OpDecorate %47 RelaxedPrecision
OpDecorate %50 RelaxedPrecision
OpDecorate %51 RelaxedPrecision
OpDecorate %52 RelaxedPrecision
%float = OpTypeFloat 32
%v4float = OpTypeVector %float 4
%_ptr_Output_v4float = OpTypePointer Output %v4float
%sk_FragColor = OpVariable %_ptr_Output_v4float Output
%bool = OpTypeBool
%_ptr_Input_bool = OpTypePointer Input %bool
%sk_Clockwise = OpVariable %_ptr_Input_bool Input
%void = OpTypeVoid
%12 = OpTypeFunction %void
%15 = OpTypeFunction %v4float
%mat4v4float = OpTypeMatrix %v4float 4
%_ptr_Function_mat4v4float = OpTypePointer Function %mat4v4float
%float_123 = OpConstant %float 123
%float_0 = OpConstant %float 0
%22 = OpConstantComposite %v4float %float_123 %float_0 %float_0 %float_0
%23 = OpConstantComposite %v4float %float_0 %float_123 %float_0 %float_0
%24 = OpConstantComposite %v4float %float_0 %float_0 %float_123 %float_0
%25 = OpConstantComposite %v4float %float_0 %float_0 %float_0 %float_123
%26 = OpConstantComposite %mat4v4float %22 %23 %24 %25
%_ptr_Function_v4float = OpTypePointer Function %v4float
%float_1 = OpConstant %float 1
%float_2 = OpConstant %float 2
%float_3 = OpConstant %float 3
%32 = OpConstantComposite %v4float %float_0 %float_1 %float_2 %float_3
%int = OpTypeInt 32 1
%int_0 = OpConstant %int 0
%int_1 = OpConstant %int 1
%int_2 = OpConstant %int 2
%int_3 = OpConstant %int 3
%_entrypoint_v = OpFunction %void None %12
%13 = OpLabel
%14 = OpFunctionCall %v4float %main
OpStore %sk_FragColor %14
OpReturn
OpFunctionEnd
%main = OpFunction %v4float None %15
%16 = OpLabel
%m44 = OpVariable %_ptr_Function_mat4v4float Function
%v4 = OpVariable %_ptr_Function_v4float Function
OpStore %m44 %26
OpStore %v4 %32
%35 = OpAccessChain %_ptr_Function_v4float %m44 %int_0
%36 = OpLoad %v4float %35
%37 = OpVectorTimesScalar %v4float %36 %float_0
%39 = OpAccessChain %_ptr_Function_v4float %m44 %int_1
%40 = OpLoad %v4float %39
%41 = OpVectorTimesScalar %v4float %40 %float_1
%42 = OpFAdd %v4float %37 %41
%44 = OpAccessChain %_ptr_Function_v4float %m44 %int_2
%45 = OpLoad %v4float %44
%46 = OpVectorTimesScalar %v4float %45 %float_2
%47 = OpFAdd %v4float %42 %46
%49 = OpAccessChain %_ptr_Function_v4float %m44 %int_3
%50 = OpLoad %v4float %49
%51 = OpVectorTimesScalar %v4float %50 %float_3
%52 = OpFAdd %v4float %47 %51
OpReturnValue %52
OpFunctionEnd