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Implement Transforms/IndVarsSimplify/complex-scev.ll, a case where we didn't
recognize some simple affine IV's. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27982 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -1295,6 +1295,31 @@ SCEVHandle ScalarEvolutionsImpl::createNodeForPHI(PHINode *PN) {
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SCEVHandle StartVal = getSCEV(PN->getIncomingValue(IncomingEdge));
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SCEVHandle PHISCEV = SCEVAddRecExpr::get(StartVal, Accum, L);
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// Okay, for the entire analysis of this edge we assumed the PHI
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// to be symbolic. We now need to go back and update all of the
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// entries for the scalars that use the PHI (except for the PHI
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// itself) to use the new analyzed value instead of the "symbolic"
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// value.
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ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV);
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return PHISCEV;
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}
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}
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} else if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(BEValue)) {
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// Otherwise, this could be a loop like this:
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// i = 0; for (j = 1; ..; ++j) { .... i = j; }
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// In this case, j = {1,+,1} and BEValue is j.
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// Because the other in-value of i (0) fits the evolution of BEValue
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// i really is an addrec evolution.
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if (AddRec->getLoop() == L && AddRec->isAffine()) {
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SCEVHandle StartVal = getSCEV(PN->getIncomingValue(IncomingEdge));
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// If StartVal = j.start - j.stride, we can use StartVal as the
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// initial step of the addrec evolution.
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if (StartVal == SCEV::getMinusSCEV(AddRec->getOperand(0),
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AddRec->getOperand(1))) {
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SCEVHandle PHISCEV =
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SCEVAddRecExpr::get(StartVal, AddRec->getOperand(1), L);
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// Okay, for the entire analysis of this edge we assumed the PHI
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// to be symbolic. We now need to go back and update all of the
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// entries for the scalars that use the PHI (except for the PHI
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