Avoid setting bits that aren't demanded.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47098 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 3ec60cd..e5ccd32 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1237,7 +1237,7 @@
KnownZero = KnownZero.lshr(ShAmt);
KnownOne = KnownOne.lshr(ShAmt);
- APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
+ APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt) & Mask;
KnownZero |= HighBits; // High bits known zero.
}
return;
@@ -1248,8 +1248,8 @@
APInt InDemandedMask = (Mask << ShAmt);
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.
- APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
- if (!!(HighBits & Mask))
+ APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt) & Mask;
+ if (HighBits.getBoolValue())
InDemandedMask |= APInt::getSignBit(BitWidth);
ComputeMaskedBits(Op.getOperand(0), InDemandedMask, KnownZero, KnownOne,