commit 334d0ba9d7a980ebed59ec9fbfdafe5090abab67
author Noah Lavine <noah.b.lavine@gmail.com> Wed Dec 18 23:03:49 2019 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Fri Dec 20 14:50:46 2019 +0000
tree df3214192a1b919e12dd5b615d44261d8a1b6167
parent 94de6b40d903a101c28653ea5565b31fa249ad5c

Optimize SkSL xor where one argument is constant

Change-Id: I9ea41625fd80433f7f6480fe539321d8df7b7930
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/258877
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>

src/sksl/SkSLIRGenerator.cpp

diff --git a/src/sksl/SkSLIRGenerator.cpp b/src/sksl/SkSLIRGenerator.cpp
index fa7c83c..9ee469e 100644
--- a/src/sksl/SkSLIRGenerator.cpp
+++ b/src/sksl/SkSLIRGenerator.cpp
@@ -1495,8 +1495,12 @@
         // (true || expr) -> (true) and (false || expr) -> (expr)
         return leftVal ? std::unique_ptr<Expression>(new BoolLiteral(context, left.fOffset, true))
                        : right.clone();
+    } else if (op == Token::LOGICALXOR) {
+        // (true ^^ expr) -> !(expr) and (false ^^ expr) -> (expr)
+        return leftVal ? std::unique_ptr<Expression>(new PrefixExpression(Token::LOGICALNOT,
+                                                                          right.clone()))
+                       : right.clone();
     } else {
-        // Can't short circuit XOR
         return nullptr;
     }
 }