diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/LICM.cpp | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp index 4ea935793b8..946474fef06 100644 --- a/lib/Transforms/Scalar/LICM.cpp +++ b/lib/Transforms/Scalar/LICM.cpp @@ -97,7 +97,7 @@ static bool hoist(Instruction &I, const DominatorTree *DT, const Loop *CurLoop, const LoopSafetyInfo *SafetyInfo, OptimizationRemarkEmitter *ORE); static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT, - const Loop *CurLoop, const LoopSafetyInfo *SafetyInfo, + const Loop *CurLoop, LoopSafetyInfo *SafetyInfo, OptimizationRemarkEmitter *ORE, bool FreeInLoop); static bool isSafeToExecuteUnconditionally(Instruction &Inst, const DominatorTree *DT, @@ -855,10 +855,16 @@ static Instruction *sinkThroughTriviallyReplacablePHI( return New; } -static bool canSplitPredecessors(PHINode *PN) { +static bool canSplitPredecessors(PHINode *PN, LoopSafetyInfo *SafetyInfo) { BasicBlock *BB = PN->getParent(); if (!BB->canSplitPredecessors()) return false; + // It's not impossible to split EHPad blocks, but if BlockColors already exist + // it require updating BlockColors for all offspring blocks accordingly. By + // skipping such corner case, we can make updating BlockColors after splitting + // predecessor fairly simple. + if (!SafetyInfo->BlockColors.empty() && BB->getFirstNonPHI()->isEHPad()) + return false; for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { BasicBlock *BBPred = *PI; if (isa<IndirectBrInst>(BBPred->getTerminator())) @@ -868,7 +874,8 @@ static bool canSplitPredecessors(PHINode *PN) { } static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT, - LoopInfo *LI, const Loop *CurLoop) { + LoopInfo *LI, const Loop *CurLoop, + LoopSafetyInfo *SafetyInfo) { #ifndef NDEBUG SmallVector<BasicBlock *, 32> ExitBlocks; CurLoop->getUniqueExitBlocks(ExitBlocks); @@ -910,13 +917,21 @@ static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT, // LE: // %p = phi [%p1, %LE.split], [%p2, %LE.split2] // + auto &BlockColors = SafetyInfo->BlockColors; SmallSetVector<BasicBlock *, 8> PredBBs(pred_begin(ExitBB), pred_end(ExitBB)); while (!PredBBs.empty()) { BasicBlock *PredBB = *PredBBs.begin(); assert(CurLoop->contains(PredBB) && "Expect all predecessors are in the loop"); - if (PN->getBasicBlockIndex(PredBB) >= 0) - SplitBlockPredecessors(ExitBB, PredBB, ".split.loop.exit", DT, LI, true); + if (PN->getBasicBlockIndex(PredBB) >= 0) { + BasicBlock *NewPred = SplitBlockPredecessors( + ExitBB, PredBB, ".split.loop.exit", DT, LI, true); + // Since we do not allow splitting EH-block with BlockColors in + // canSplitPredecessors(), we can simply assign predecessor's color to + // the new block. + if (!BlockColors.empty()) + BlockColors[NewPred] = BlockColors[PredBB]; + } PredBBs.remove(PredBB); } } @@ -927,7 +942,7 @@ static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT, /// position, and may either delete it or move it to outside of the loop. /// static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT, - const Loop *CurLoop, const LoopSafetyInfo *SafetyInfo, + const Loop *CurLoop, LoopSafetyInfo *SafetyInfo, OptimizationRemarkEmitter *ORE, bool FreeInLoop) { DEBUG(dbgs() << "LICM sinking instruction: " << I << "\n"); ORE->emit([&]() { @@ -975,12 +990,12 @@ static bool sink(Instruction &I, LoopInfo *LI, DominatorTree *DT, if (isTriviallyReplacablePHI(*PN, I)) continue; - if (!canSplitPredecessors(PN)) + if (!canSplitPredecessors(PN, SafetyInfo)) return Changed; // Split predecessors of the PHI so that we can make users trivially // replacable. - splitPredecessorsOfLoopExit(PN, DT, LI, CurLoop); + splitPredecessorsOfLoopExit(PN, DT, LI, CurLoop, SafetyInfo); // Should rebuild the iterators, as they may be invalidated by // splitPredecessorsOfLoopExit(). |