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[CodeGenPrepare][AddressingModeMatcher] Fix a think-o for the sext(zext) -> zext promotion

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introduced in r217629.
We were returning the old sext instead of the new zext as the promoted instruction!

Thanks Joerg Sonnenberger for the test case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217800 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Quentin Colombet
2014-09-15 18:26:58 +00:00
parent 348e9e7b6d
commit 49e423ca30
2 changed files with 72 additions and 7 deletions
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16
lib/CodeGen/CodeGenPrepare.cpp
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@ -1849,6 +1849,7 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
// By construction, the operand of SExt is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
Instruction *ExtInst = SExt;
if (isa<ZExtInst>(SExtOpnd)) {
// Replace sext(zext(opnd))
// => zext(opnd).
@ -1856,6 +1857,7 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
TPT.replaceAllUsesWith(SExt, ZExt);
TPT.eraseInstruction(SExt);
ExtInst = ZExt;
} else {
// Replace sext(trunc(opnd)) or sext(sext(opnd))
// => sext(opnd).
@ -1867,14 +1869,14 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
if (SExtOpnd->use_empty())
TPT.eraseInstruction(SExtOpnd);
// Check if the sext is still needed.
if (SExt->getType() != SExt->getOperand(0)->getType())
return SExt;
// Check if the extension is still needed.
if (ExtInst->getType() != ExtInst->getOperand(0)->getType())
return ExtInst;
// At this point we have: sext ty opnd to ty.
// Reassign the uses of SExt to the opnd and remove SExt.
Value *NextVal = SExt->getOperand(0);
TPT.eraseInstruction(SExt, NextVal);
// At this point we have: ext ty opnd to ty.
// Reassign the uses of ExtInst to the opnd and remove ExtInst.
Value *NextVal = ExtInst->getOperand(0);
TPT.eraseInstruction(ExtInst, NextVal);
return NextVal;
}