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Implement mul.ll:test11 

llvm-svn: 11737
This commit is contained in:
Chris Lattner 2004-02-23 06:00:11 +00:00
parent fb302df02c
commit c8a10c4b6a
1 changed files with 7 additions and 6 deletions
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13
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -616,12 +616,13 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
Value *SCIOp0 = SCI->getOperand(0), *SCIOp1 = SCI->getOperand(1);
const Type *SCOpTy = SCIOp0->getType();
// If the source is X < 0, and X is a signed integer type, convert this
// multiply into a shift/and combination.
if (SCI->getOpcode() == Instruction::SetLT &&
isa<Constant>(SCIOp1) && cast<Constant>(SCIOp1)->isNullValue() &&
SCOpTy->isInteger() && SCOpTy->isSigned()) {
// If the source is X < 0 or X <= -1, and X is a signed integer type,
// convert this multiply into a shift/and combination.
if (SCOpTy->isSigned() && isa<ConstantInt>(SCIOp1) &&
((SCI->getOpcode() == Instruction::SetLT &&
cast<Constant>(SCIOp1)->isNullValue()) ||
(SCI->getOpcode() == Instruction::SetLE &&
cast<ConstantInt>(SCIOp1)->isAllOnesValue()))) {
// Shift the X value right to turn it into "all signbits".
Constant *Amt = ConstantUInt::get(Type::UByteTy,
SCOpTy->getPrimitiveSize()*8-1);