PR10267: Don't combine an equality compare with an AND into an inequality compare when the AND has more than one use.

This can pessimize code, inequalities are generally more expensive.

llvm-svn: 134379

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 42db444ff6d..5a1e2b08853 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1454,7 +1454,11 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
             return new ICmpInst(isICMP_NE ? ICmpInst::ICMP_EQ :
                                 ICmpInst::ICMP_NE, LHSI,
                                 Constant::getNullValue(RHS->getType()));
-          
+
+          // Don't perform the following transforms if the AND has multiple uses
+          if (!BO->hasOneUse())
+            break;
+
           // Replace (and X, (1 << size(X)-1) != 0) with x s< 0
           if (BOC->getValue().isSignBit()) {
             Value *X = BO->getOperand(0);