commit 856fd686908aac7edb37f1013874cb79c84de5bc
author Craig Topper <craig.topper@intel.com> Thu May 03 05:48:49 2018 +0000
committer Craig Topper <craig.topper@intel.com> Thu May 03 05:48:49 2018 +0000
tree 1c1e08c22c2e6ad5456d83bbf2caa837f0e74c3f
parent a0cba89f861da4cba80c28a1d3cf30c8e0fb436e

[LoopIdiomRecognize] When looking for 'x & (x -1)' for popcnt, make sure the left hand side of the 'and' matches the left hand side of the 'subtract'

llvm-svn: 331437

llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index fc64058..5975357 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -1196,7 +1196,7 @@
       VarX1 = DefX2->getOperand(0);
       SubOneOp = dyn_cast<BinaryOperator>(DefX2->getOperand(1));
     }
-    if (!SubOneOp)
+    if (!SubOneOp || SubOneOp->getOperand(0) != VarX1)
       return false;
 
     ConstantInt *Dec = dyn_cast<ConstantInt>(SubOneOp->getOperand(1));