From 95d25d39d070029128397204289e51e39cbc3d86 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Wed, 13 Feb 2008 22:43:25 +0000 Subject: [PATCH] Avoid setting bits that aren't demanded. llvm-svn: 47098 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 3ec60cde9d7c..e5ccd3217564 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1237,7 +1237,7 @@ void SelectionDAG::ComputeMaskedBits(SDOperand Op, const APInt &Mask, 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 @@ void SelectionDAG::ComputeMaskedBits(SDOperand Op, const APInt &Mask, 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,