forked from OSchip/llvm-project
parent
cdb2465152
commit
a816eee427
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@ -2879,6 +2879,22 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
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if (Constant *RHSC = dyn_cast<Constant>(Op1)) {
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if (Instruction *LHSI = dyn_cast<Instruction>(Op0))
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switch (LHSI->getOpcode()) {
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case Instruction::GetElementPtr:
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if (RHSC->isNullValue()) {
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// Transform setcc GEP P, int 0, int 0, int 0, null -> setcc P, null
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bool isAllZeros = true;
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for (unsigned i = 1, e = LHSI->getNumOperands(); i != e; ++i)
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if (!isa<Constant>(LHSI->getOperand(i)) ||
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!cast<Constant>(LHSI->getOperand(i))->isNullValue()) {
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isAllZeros = false;
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break;
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}
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if (isAllZeros)
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return new SetCondInst(I.getOpcode(), LHSI->getOperand(0),
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Constant::getNullValue(LHSI->getOperand(0)->getType()));
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}
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break;
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case Instruction::PHI:
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if (Instruction *NV = FoldOpIntoPhi(I))
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return NV;
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