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fix a miscompilation of 176.gcc 

llvm-svn: 33900
This commit is contained in:
Chris Lattner 2007-02-05 04:09:35 +00:00
parent 4e76c3a482
commit 0a28e90f2c
1 changed files with 2 additions and 2 deletions
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4
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -5647,12 +5647,12 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
if (ShiftAmt1 == ShiftAmt2) {
// If we have ((X >>? C) << C), turn this into X & (-1 << C).
if (I.getOpcode() == Instruction::Shl) {
uint64_t Mask = -1ULL << ShiftAmt1;
uint64_t Mask = Ty->getBitMask() << ShiftAmt1;
return BinaryOperator::createAnd(X, ConstantInt::get(Ty, Mask));
}
// If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
if (I.getOpcode() == Instruction::LShr) {
uint64_t Mask = -1ULL >> ShiftAmt1;
uint64_t Mask = Ty->getBitMask() >> ShiftAmt1;
return BinaryOperator::createAnd(X, ConstantInt::get(Ty, Mask));
}
// We can simplify ((X << C) >>s C) into a trunc + sext.