Re-apply 55137 with fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58296 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Greene 2008-10-27 23:24:03 +00:00
parent b3990d5e94
commit c714f13090

View File

@ -509,12 +509,15 @@ 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);
ComputeMaskedBits(L, Mask2, KnownZero3, KnownOne3, TD, Depth+1);
KnownZero = Mask &
APInt::getLowBitsSet(BitWidth,
KnownZero2.countTrailingOnes());
std::min(KnownZero2.countTrailingOnes(),
KnownZero3.countTrailingOnes()));
break;
}
}