commit 118706a80660177ece10936c3730a6bb804f2358
author John Stiles <johnstiles@google.com> Fri Oct 09 10:07:38 2020 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Fri Oct 09 17:39:33 2020 +0000
tree 9e4cff51d0fc1423ef3831e38b804b8e2abddcd9
parent f52bca10695bb9f639d2d3e4b8eeb11aa8a6a346

Improve codegen for gradients.

Replacing `sk_OutColor = x` with `return x` in single-exit FP functions
results in fewer scratch variables in the final post-inliner output.

Change-Id: I81c081a78d0fb7dfad5230e3044027901673236c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/324377
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

src/gpu/gradients/generated/GrSweepGradientLayout.cpp

diff --git a/src/gpu/gradients/generated/GrSweepGradientLayout.cpp b/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
index cb44776..0cf2336 100644
--- a/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
+++ b/src/gpu/gradients/generated/GrSweepGradientLayout.cpp
@@ -33,18 +33,13 @@
         scaleVar = args.fUniformHandler->addUniform(&_outer, kFragment_GrShaderFlag, kHalf_GrSLType,
                                                     "scale");
         fragBuilder->codeAppendf(
-                R"SkSL(half angle;
-if (sk_Caps.atan2ImplementedAsAtanYOverX) {
-    angle = half(2.0 * atan(-%s.y, length(%s) - %s.x));
-} else {
-    angle = half(atan(-%s.y, -%s.x));
-}
+                R"SkSL(half angle = sk_Caps.atan2ImplementedAsAtanYOverX ? half(2.0 * atan(-%s.y, length(%s) - %s.x)) : half(atan(-%s.y, -%s.x));
 half t = ((angle * 0.15915493667125702 + 0.5) + %s) * %s;
-%s = half4(t, 1.0, 0.0, 0.0);
+return half4(t, 1.0, 0.0, 0.0);
 )SkSL",
                 args.fSampleCoord, args.fSampleCoord, args.fSampleCoord, args.fSampleCoord,
                 args.fSampleCoord, args.fUniformHandler->getUniformCStr(biasVar),
-                args.fUniformHandler->getUniformCStr(scaleVar), args.fOutputColor);
+                args.fUniformHandler->getUniformCStr(scaleVar));
     }
 
 private:
@@ -81,7 +76,7 @@
     if (scale != that.scale) return false;
     return true;
 }
-bool GrSweepGradientLayout::usesExplicitReturn() const { return false; }
+bool GrSweepGradientLayout::usesExplicitReturn() const { return true; }
 GrSweepGradientLayout::GrSweepGradientLayout(const GrSweepGradientLayout& src)
         : INHERITED(kGrSweepGradientLayout_ClassID, src.optimizationFlags())
         , bias(src.bias)