diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/LCSSA.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LCSSA.cpp | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp index 183e0a4..c36b053 100644 --- a/llvm/lib/Transforms/Utils/LCSSA.cpp +++ b/llvm/lib/Transforms/Utils/LCSSA.cpp @@ -148,13 +148,10 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist, SSAUpdater SSAUpdate(&LocalInsertedPHIs); SSAUpdate.Initialize(I->getType(), I->getName()); - // Force re-computation of I, as some users now need to use the new PHI - // node. - if (SE) - SE->forgetValue(I); - // Insert the LCSSA phi's into all of the exit blocks dominated by the // value, and add them to the Phi's map. + bool HasSCEV = SE && SE->isSCEVable(I->getType()) && + SE->getExistingSCEV(I) != nullptr; for (BasicBlock *ExitBB : ExitBlocks) { if (!DT.dominates(DomNode, DT.getNode(ExitBB))) continue; @@ -202,6 +199,13 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist, if (auto *OtherLoop = LI.getLoopFor(ExitBB)) if (!L->contains(OtherLoop)) PostProcessPHIs.push_back(PN); + + // If we have a cached SCEV for the original instruction, make sure the + // new LCSSA phi node is also cached. This makes sures that BECounts + // based on it will be invalidated when the LCSSA phi node is invalidated, + // which some passes rely on. + if (HasSCEV) + SE->getSCEV(PN); } // Rewrite all uses outside the loop in terms of the new PHIs we just |