commit 3711c6603ee4f183dfb387c7909b46797ae806ef
author Brian Osman <brianosman@google.com> Thu Jun 18 14:42:21 2020 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Jun 18 19:26:02 2020 +0000
tree e0b83458c31e880752407a22f9409ef8384b28fd
parent f847f3106cfb84ccef3500f0f17418a3e43abc04

Remove swizzling-load instructions from SkSL ByteCode

These were peephole optimizations that help the interpreter a bit, but
I'd like to favor code size and ease of translation to SkVM now.
We can now run: sample(child, p.yx) on the CPU backend, for example.

Change-Id: I90f2f649d95d5c4c50e470988590491e3b56ba34
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297465
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>

src/sksl/SkSLByteCodeGenerator.cpp

diff --git a/src/sksl/SkSLByteCodeGenerator.cpp b/src/sksl/SkSLByteCodeGenerator.cpp
index b05fe2b..7983e7e 100644
--- a/src/sksl/SkSLByteCodeGenerator.cpp
+++ b/src/sksl/SkSLByteCodeGenerator.cpp
@@ -364,9 +364,6 @@
             return 4;
 
         case ByteCodeInstruction::kDupN:
-        case ByteCodeInstruction::kLoadSwizzle:
-        case ByteCodeInstruction::kLoadSwizzleGlobal:
-        case ByteCodeInstruction::kLoadSwizzleUniform:
             return count;
 
         // Pushes 'count' values, minus one for the 'address' that's consumed first
@@ -1428,29 +1425,12 @@
         return;
     }
 
-    switch (s.fBase->fKind) {
-        case Expression::kVariableReference_Kind: {
-            Location location = this->getLocation(*s.fBase);
-            this->write(location.selectLoad(ByteCodeInstruction::kLoadSwizzle,
-                                            ByteCodeInstruction::kLoadSwizzleGlobal,
-                                            ByteCodeInstruction::kLoadSwizzleUniform),
-                        s.fComponents.size());
-            this->write8(location.fSlot);
-            this->write8(s.fComponents.size());
-            for (int c : s.fComponents) {
-                this->write8(c);
-            }
-            break;
-        }
-        default:
-            this->writeExpression(*s.fBase);
-            this->write(ByteCodeInstruction::kSwizzle,
-                        s.fComponents.size() - s.fBase->fType.columns());
-            this->write8(s.fBase->fType.columns());
-            this->write8(s.fComponents.size());
-            for (int c : s.fComponents) {
-                this->write8(c);
-            }
+    this->writeExpression(*s.fBase);
+    this->write(ByteCodeInstruction::kSwizzle, s.fComponents.size() - s.fBase->fType.columns());
+    this->write8(s.fBase->fType.columns());
+    this->write8(s.fComponents.size());
+    for (int c : s.fComponents) {
+        this->write8(c);
     }
 }