77702f1704
When we determine that a function only contains a single return
statement and it is at the top level (i.e. not inside any scopes),
there is no need to create a temporary variable and store the
result expression into a variable. Instead, we can directly replace
the function-call expression with the return-statement's expression.
Unlike my previous solution, this does not require variable
declarations to be rewritten. The no-scopes limitation makes it
slightly less effective in theory, but in practice we still get
almost all of the benefit. The no-scope limitation bites us on
structures like
@if (true) {
return x;
} else {
return y;
}
Which will optimize away the if, but leave the scope:
{
return x;
}
However, this is not a big deal; the biggest wins are single-line
helper functions like `guarded_divide` and `unpremul` which retain
the full benefit.
Change-Id: I7fbb725e65db021b9795c04c816819669815578f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/345167
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
76 lines
2.5 KiB
JavaScript
76 lines
2.5 KiB
JavaScript
OpCapability Shader
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%1 = OpExtInstImport "GLSL.std.450"
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OpMemoryModel Logical GLSL450
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OpEntryPoint Fragment %main "main" %sk_FragColor %sk_Clockwise %src %dst
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OpExecutionMode %main OriginUpperLeft
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OpName %sk_FragColor "sk_FragColor"
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OpName %sk_Clockwise "sk_Clockwise"
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OpName %src "src"
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OpName %dst "dst"
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OpName %main "main"
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OpDecorate %sk_FragColor RelaxedPrecision
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OpDecorate %sk_FragColor Location 0
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OpDecorate %sk_FragColor Index 0
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OpDecorate %sk_Clockwise RelaxedPrecision
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OpDecorate %sk_Clockwise BuiltIn FrontFacing
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OpDecorate %src RelaxedPrecision
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OpDecorate %dst RelaxedPrecision
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OpDecorate %16 RelaxedPrecision
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OpDecorate %19 RelaxedPrecision
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OpDecorate %21 RelaxedPrecision
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OpDecorate %23 RelaxedPrecision
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OpDecorate %26 RelaxedPrecision
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OpDecorate %28 RelaxedPrecision
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OpDecorate %29 RelaxedPrecision
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OpDecorate %33 RelaxedPrecision
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OpDecorate %36 RelaxedPrecision
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OpDecorate %38 RelaxedPrecision
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OpDecorate %39 RelaxedPrecision
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OpDecorate %41 RelaxedPrecision
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OpDecorate %42 RelaxedPrecision
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%float = OpTypeFloat 32
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%v4float = OpTypeVector %float 4
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%_ptr_Output_v4float = OpTypePointer Output %v4float
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%sk_FragColor = OpVariable %_ptr_Output_v4float Output
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%bool = OpTypeBool
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%_ptr_Input_bool = OpTypePointer Input %bool
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%sk_Clockwise = OpVariable %_ptr_Input_bool Input
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%_ptr_Input_v4float = OpTypePointer Input %v4float
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%src = OpVariable %_ptr_Input_v4float Input
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%dst = OpVariable %_ptr_Input_v4float Input
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%void = OpTypeVoid
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%14 = OpTypeFunction %void
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%v3float = OpTypeVector %float 3
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%float_2 = OpConstant %float 2
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%float_1 = OpConstant %float 1
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%main = OpFunction %void None %14
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%15 = OpLabel
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%16 = OpLoad %v4float %dst
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%17 = OpVectorShuffle %v3float %16 %16 0 1 2
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%19 = OpLoad %v4float %src
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%20 = OpVectorShuffle %v3float %19 %19 0 1 2
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%21 = OpFAdd %v3float %17 %20
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%23 = OpLoad %v4float %dst
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%24 = OpVectorShuffle %v3float %23 %23 0 1 2
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%25 = OpVectorTimesScalar %v3float %24 %float_2
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%26 = OpLoad %v4float %src
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%27 = OpVectorShuffle %v3float %26 %26 0 1 2
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%28 = OpFMul %v3float %25 %27
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%29 = OpFSub %v3float %21 %28
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%30 = OpCompositeExtract %float %29 0
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%31 = OpCompositeExtract %float %29 1
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%32 = OpCompositeExtract %float %29 2
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%33 = OpLoad %v4float %src
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%34 = OpCompositeExtract %float %33 3
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%36 = OpLoad %v4float %src
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%37 = OpCompositeExtract %float %36 3
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%38 = OpFSub %float %float_1 %37
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%39 = OpLoad %v4float %dst
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%40 = OpCompositeExtract %float %39 3
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%41 = OpFMul %float %38 %40
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%42 = OpFAdd %float %34 %41
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%43 = OpCompositeConstruct %v4float %30 %31 %32 %42
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OpStore %sk_FragColor %43
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OpReturn
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OpFunctionEnd
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