diff options
Diffstat (limited to 'lib/Transforms/Utils/LCSSA.cpp')
| -rw-r--r-- | lib/Transforms/Utils/LCSSA.cpp | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/Transforms/Utils/LCSSA.cpp b/lib/Transforms/Utils/LCSSA.cpp index b654111eba..833dea5471 100644 --- a/lib/Transforms/Utils/LCSSA.cpp +++ b/lib/Transforms/Utils/LCSSA.cpp @@ -53,6 +53,8 @@ namespace { // Cached analysis information for the current function. DominatorTree *DT; + LoopInfo *LI; + ScalarEvolution *SE; std::vector<BasicBlock*> LoopBlocks; PredIteratorCache PredCache; Loop *L; @@ -117,6 +119,8 @@ bool LCSSA::runOnLoop(Loop *TheLoop, LPPassManager &LPM) { L = TheLoop; DT = &getAnalysis<DominatorTree>(); + LI = &getAnalysis<LoopInfo>(); + SE = getAnalysisIfAvailable<ScalarEvolution>(); // Get the set of exiting blocks. SmallVector<BasicBlock*, 8> ExitBlocks; @@ -244,6 +248,12 @@ bool LCSSA::ProcessInstruction(Instruction *Inst, // Remember that this phi makes the value alive in this block. SSAUpdate.AddAvailableValue(ExitBB, PN); + + // If the exiting block is part of a loop inserting a PHI may change its + // SCEV analysis. Conservatively drop any caches from it. + if (SE) + if (Loop *L = LI->getLoopFor(ExitBB)) + SE->forgetLoop(L); } // Rewrite all uses outside the loop in terms of the new PHIs we just @@ -258,6 +268,10 @@ bool LCSSA::ProcessInstruction(Instruction *Inst, if (PHINode *PN = dyn_cast<PHINode>(User)) UserBB = PN->getIncomingBlock(*UsesToRewrite[i]); + // Tell SCEV to reanalyze the value that's about to change. + if (SE) + SE->forgetValue(*UsesToRewrite[i]); + if (isa<PHINode>(UserBB->begin()) && isExitBlock(UserBB, ExitBlocks)) { UsesToRewrite[i]->set(UserBB->begin()); |