skia2/tests/sksl/shared/DependentInitializers.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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3.0 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 "colorGreen"
OpMemberName %_UniformBuffer 1 "colorRed"
OpName %_entrypoint_v "_entrypoint_v"
OpName %main "main"
OpName %x "x"
OpName %y "y"
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
OpMemberDecorate %_UniformBuffer 1 Offset 16
OpMemberDecorate %_UniformBuffer 1 RelaxedPrecision
OpDecorate %_UniformBuffer Block
OpDecorate %10 Binding 0
OpDecorate %10 DescriptorSet 0
OpDecorate %43 RelaxedPrecision
OpDecorate %46 RelaxedPrecision
OpDecorate %47 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 %v4float %v4float
%_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_float = OpTypePointer Function %float
%float_0_5 = OpConstant %float 0.5
%float_2 = OpConstant %float 2
%float_1 = OpConstant %float 1
%_ptr_Function_v4float = OpTypePointer Function %v4float
%_ptr_Uniform_v4float = OpTypePointer Uniform %v4float
%int = OpTypeInt 32 1
%int_0 = OpConstant %int 0
%int_1 = OpConstant %int 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
%x = OpVariable %_ptr_Function_float Function
%y = OpVariable %_ptr_Function_float Function
%34 = OpVariable %_ptr_Function_v4float Function
OpStore %x %float_0_5
%31 = OpFMul %float %float_0_5 %float_2
OpStore %y %31
%33 = OpFOrdEqual %bool %31 %float_1
OpSelectionMerge %38 None
OpBranchConditional %33 %36 %37
%36 = OpLabel
%39 = OpAccessChain %_ptr_Uniform_v4float %10 %int_0
%43 = OpLoad %v4float %39
OpStore %34 %43
OpBranch %38
%37 = OpLabel
%44 = OpAccessChain %_ptr_Uniform_v4float %10 %int_1
%46 = OpLoad %v4float %44
OpStore %34 %46
OpBranch %38
%38 = OpLabel
%47 = OpLoad %v4float %34
OpReturnValue %47
OpFunctionEnd