diff options
Diffstat (limited to 'lib/Analysis/ScalarEvolution.cpp')
-rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 1ab6a40..f65cf34 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -4844,12 +4844,12 @@ ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN, // EvaluateExpression adds non-phi values to the CurrentIterVals map. DenseMap<Instruction *, Constant *> NextIterVals; Constant *NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD); - if (NextPHI == CurrentIterVals[PN]) - return RetVal = NextPHI; // Stopped evolving! if (NextPHI == 0) return 0; // Couldn't evaluate! NextIterVals[PN] = NextPHI; + bool StoppedEvolving = NextPHI == CurrentIterVals[PN]; + // Also evaluate the other PHI nodes. However, we don't get to stop if we // cease to be able to evaluate one of them or if they stop evolving, // because that doesn't necessarily prevent us from computing PN. @@ -4858,11 +4858,19 @@ ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN, PHINode *PHI = dyn_cast<PHINode>(I->first); if (!PHI || PHI == PN || PHI->getParent() != Header) continue; Constant *&NextPHI = NextIterVals[PHI]; - if (NextPHI) continue; // Already computed! - - Value *BEValue = PHI->getIncomingValue(SecondIsBackedge); - NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD); + if (!NextPHI) { // Not already computed. + Value *BEValue = PHI->getIncomingValue(SecondIsBackedge); + NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD); + } + if (NextPHI != I->second) + StoppedEvolving = false; } + + // If all entries in CurrentIterVals == NextIterVals then we can stop + // iterating, the loop can't continue to change. + if (StoppedEvolving) + return RetVal = CurrentIterVals[PN]; + CurrentIterVals.swap(NextIterVals); } } |