skia2/tests/sksl/shared/SwizzleScalar.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

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3.2 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 %_UniformBuffer "_UniformBuffer"
OpMemberName %_UniformBuffer 0 "unknownInput"
OpName %_entrypoint_v "_entrypoint_v"
OpName %main "main"
OpName %h4 "h4"
OpDecorate %sk_FragColor RelaxedPrecision
OpDecorate %sk_FragColor Location 0
OpDecorate %sk_FragColor Index 0
OpDecorate %sk_Clockwise BuiltIn FrontFacing
OpMemberDecorate %_UniformBuffer 0 Offset 0
OpMemberDecorate %_UniformBuffer 0 RelaxedPrecision
OpDecorate %_UniformBuffer Block
OpDecorate %10 Binding 0
OpDecorate %10 DescriptorSet 0
OpDecorate %h4 RelaxedPrecision
OpDecorate %32 RelaxedPrecision
OpDecorate %33 RelaxedPrecision
OpDecorate %35 RelaxedPrecision
OpDecorate %36 RelaxedPrecision
OpDecorate %37 RelaxedPrecision
OpDecorate %38 RelaxedPrecision
OpDecorate %40 RelaxedPrecision
OpDecorate %42 RelaxedPrecision
OpDecorate %43 RelaxedPrecision
OpDecorate %45 RelaxedPrecision
OpDecorate %47 RelaxedPrecision
OpDecorate %48 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
%_UniformBuffer = OpTypeStruct %float
%_ptr_Uniform__UniformBuffer = OpTypePointer Uniform %_UniformBuffer
%10 = OpVariable %_ptr_Uniform__UniformBuffer Uniform
%void = OpTypeVoid
%15 = OpTypeFunction %void
%float_0 = OpConstant %float 0
%v2float = OpTypeVector %float 2
%19 = OpConstantComposite %v2float %float_0 %float_0
%_ptr_Function_v2float = OpTypePointer Function %v2float
%23 = OpTypeFunction %v4float %_ptr_Function_v2float
%_ptr_Function_v4float = OpTypePointer Function %v4float
%_ptr_Uniform_float = OpTypePointer Uniform %float
%int = OpTypeInt 32 1
%int_0 = OpConstant %int 0
%float_1 = OpConstant %float 1
%_entrypoint_v = OpFunction %void None %15
%16 = OpLabel
%20 = OpVariable %_ptr_Function_v2float Function
OpStore %20 %19
%22 = OpFunctionCall %v4float %main %20
OpStore %sk_FragColor %22
OpReturn
OpFunctionEnd
%main = OpFunction %v4float None %23
%24 = OpFunctionParameter %_ptr_Function_v2float
%25 = OpLabel
%h4 = OpVariable %_ptr_Function_v4float Function
%28 = OpAccessChain %_ptr_Uniform_float %10 %int_0
%32 = OpLoad %float %28
%33 = OpCompositeConstruct %v4float %32 %32 %32 %32
OpStore %h4 %33
%34 = OpAccessChain %_ptr_Uniform_float %10 %int_0
%35 = OpLoad %float %34
%36 = OpCompositeConstruct %v2float %35 %35
%37 = OpCompositeExtract %float %36 0
%38 = OpCompositeExtract %float %36 1
%40 = OpCompositeConstruct %v4float %37 %38 %float_0 %float_1
OpStore %h4 %40
%41 = OpAccessChain %_ptr_Uniform_float %10 %int_0
%42 = OpLoad %float %41
%43 = OpCompositeConstruct %v4float %float_0 %42 %float_1 %float_0
OpStore %h4 %43
%44 = OpAccessChain %_ptr_Uniform_float %10 %int_0
%45 = OpLoad %float %44
%46 = OpAccessChain %_ptr_Uniform_float %10 %int_0
%47 = OpLoad %float %46
%48 = OpCompositeConstruct %v4float %float_0 %45 %float_0 %47
OpStore %h4 %48
OpReturnValue %48
OpFunctionEnd