From dce51c372a9b22aaaca4d8258aa63a336c40e5fd Mon Sep 17 00:00:00 2001 From: David Greene Date: Thu, 21 Aug 2008 20:45:12 +0000 Subject: [PATCH] Fix ComputeMaskedBits to handle phis correctly. We need to take the minimum of the known zeros. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55137 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 3a04f5eb869..b956d390a81 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -509,9 +509,13 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, ComputeMaskedBits(R, Mask2, KnownZero2, KnownOne2, TD, Depth+1); Mask2 = APInt::getLowBitsSet(BitWidth, KnownZero2.countTrailingOnes()); - KnownOne2.clear(); - KnownZero2.clear(); - ComputeMaskedBits(L, Mask2, KnownZero2, KnownOne2, TD, Depth+1); + + // We need to take the minimum number of known bits + APInt KnownZero3(KnownZero), KnownOne3(KnownOne); + KnownOne3.clear(); + KnownZero3.clear(); + ComputeMaskedBits(L, Mask2, KnownZero3, KnownOne3, TD, Depth+1); + KnownZero = Mask & APInt::getLowBitsSet(BitWidth, KnownZero2.countTrailingOnes());