[llvm-commits] [llvm] r47098 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Dan Gohman
gohman at apple.com
Wed Feb 13 14:43:25 PST 2008
Author: djg
Date: Wed Feb 13 16:43:25 2008
New Revision: 47098
URL: http://llvm.org/viewvc/llvm-project?rev=47098&view=rev
Log:
Avoid setting bits that aren't demanded.
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=47098&r1=47097&r2=47098&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Wed Feb 13 16:43:25 2008
@@ -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,
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