Fix an overaggressive SimplifyDemandedBits optimization on urem. This
fixes the 254.gap regression on x86 and the 403.gcc regression on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50537 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 507e6f2..ce052f7 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -1762,11 +1762,12 @@
APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0);
APInt AllOnes = APInt::getAllOnesValue(BitWidth);
- ComputeMaskedBits(I->getOperand(0), AllOnes,
- KnownZero2, KnownOne2, Depth+1);
+ if (SimplifyDemandedBits(I->getOperand(0), AllOnes,
+ KnownZero2, KnownOne2, Depth+1))
+ return true;
+
uint32_t Leaders = KnownZero2.countLeadingOnes();
- APInt HighZeros = APInt::getHighBitsSet(BitWidth, Leaders);
- if (SimplifyDemandedBits(I->getOperand(1), ~HighZeros,
+ if (SimplifyDemandedBits(I->getOperand(1), AllOnes,
KnownZero2, KnownOne2, Depth+1))
return true;