Changes in directory llvm/lib/Analysis:
ScalarEvolution.cpp updated: 1.47 -> 1.48 --- Log message: Implement Transforms/IndVarsSimplify/complex-scev.ll, a case where we didn't recognize some simple affine IV's. --- Diffs of the changes: (+25 -0) ScalarEvolution.cpp | 25 +++++++++++++++++++++++++ 1 files changed, 25 insertions(+) Index: llvm/lib/Analysis/ScalarEvolution.cpp diff -u llvm/lib/Analysis/ScalarEvolution.cpp:1.47 llvm/lib/Analysis/ScalarEvolution.cpp:1.48 --- llvm/lib/Analysis/ScalarEvolution.cpp:1.47 Tue Apr 4 01:11:42 2006 +++ llvm/lib/Analysis/ScalarEvolution.cpp Wed Apr 26 13:34:07 2006 @@ -1304,6 +1304,31 @@ return PHISCEV; } } + } else if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(BEValue)) { + // Otherwise, this could be a loop like this: + // i = 0; for (j = 1; ..; ++j) { .... i = j; } + // In this case, j = {1,+,1} and BEValue is j. + // Because the other in-value of i (0) fits the evolution of BEValue + // i really is an addrec evolution. + if (AddRec->getLoop() == L && AddRec->isAffine()) { + SCEVHandle StartVal = getSCEV(PN->getIncomingValue(IncomingEdge)); + + // If StartVal = j.start - j.stride, we can use StartVal as the + // initial step of the addrec evolution. + if (StartVal == SCEV::getMinusSCEV(AddRec->getOperand(0), + AddRec->getOperand(1))) { + SCEVHandle PHISCEV = + SCEVAddRecExpr::get(StartVal, AddRec->getOperand(1), L); + + // Okay, for the entire analysis of this edge we assumed the PHI + // to be symbolic. We now need to go back and update all of the + // entries for the scalars that use the PHI (except for the PHI + // itself) to use the new analyzed value instead of the "symbolic" + // value. + ReplaceSymbolicValueWithConcrete(PN, SymbolicName, PHISCEV); + return PHISCEV; + } + } } return SymbolicName; _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits