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author | Dimitry Andric <dim@FreeBSD.org> | 2015-05-27 18:44:32 +0000 |
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committer | Dimitry Andric <dim@FreeBSD.org> | 2015-05-27 18:44:32 +0000 |
commit | 5a5ac124e1efaf208671f01c46edb15f29ed2a0b (patch) | |
tree | a6140557876943cdd800ee997c9317283394b22c /lib/Transforms/Utils/BreakCriticalEdges.cpp | |
parent | f03b5bed27d0d2eafd68562ce14f8b5e3f1f0801 (diff) | |
download | src-5a5ac124e1efaf208671f01c46edb15f29ed2a0b.tar.gz src-5a5ac124e1efaf208671f01c46edb15f29ed2a0b.zip |
Notes
Diffstat (limited to 'lib/Transforms/Utils/BreakCriticalEdges.cpp')
-rw-r--r-- | lib/Transforms/Utils/BreakCriticalEdges.cpp | 63 |
1 files changed, 27 insertions, 36 deletions
diff --git a/lib/Transforms/Utils/BreakCriticalEdges.cpp b/lib/Transforms/Utils/BreakCriticalEdges.cpp index eda22cfc1bab..7e83c9eeceb7 100644 --- a/lib/Transforms/Utils/BreakCriticalEdges.cpp +++ b/lib/Transforms/Utils/BreakCriticalEdges.cpp @@ -18,6 +18,7 @@ #include "llvm/Transforms/Scalar.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/CFG.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/IR/CFG.h" @@ -41,14 +42,19 @@ namespace { } bool runOnFunction(Function &F) override { - unsigned N = SplitAllCriticalEdges(F, this); + auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>(); + auto *DT = DTWP ? &DTWP->getDomTree() : nullptr; + auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>(); + auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr; + unsigned N = + SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI)); NumBroken += N; return N > 0; } void getAnalysisUsage(AnalysisUsage &AU) const override { AU.addPreserved<DominatorTreeWrapperPass>(); - AU.addPreserved<LoopInfo>(); + AU.addPreserved<LoopInfoWrapperPass>(); // No loop canonicalization guarantees are broken by this pass. AU.addPreservedID(LoopSimplifyID); @@ -125,10 +131,9 @@ static void createPHIsForSplitLoopExit(ArrayRef<BasicBlock *> Preds, /// to. /// BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, - Pass *P, bool MergeIdenticalEdges, - bool DontDeleteUselessPhis, - bool SplitLandingPads) { - if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return nullptr; + const CriticalEdgeSplittingOptions &Options) { + if (!isCriticalEdge(TI, SuccNum, Options.MergeIdenticalEdges)) + return nullptr; assert(!isa<IndirectBrInst>(TI) && "Cannot split critical edge from IndirectBrInst"); @@ -179,29 +184,22 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, // If there are any other edges from TIBB to DestBB, update those to go // through the split block, making those edges non-critical as well (and // reducing the number of phi entries in the DestBB if relevant). - if (MergeIdenticalEdges) { + if (Options.MergeIdenticalEdges) { for (unsigned i = SuccNum+1, e = TI->getNumSuccessors(); i != e; ++i) { if (TI->getSuccessor(i) != DestBB) continue; // Remove an entry for TIBB from DestBB phi nodes. - DestBB->removePredecessor(TIBB, DontDeleteUselessPhis); + DestBB->removePredecessor(TIBB, Options.DontDeleteUselessPHIs); // We found another edge to DestBB, go to NewBB instead. TI->setSuccessor(i, NewBB); } } - - - // If we don't have a pass object, we can't update anything... - if (!P) return NewBB; - - DominatorTreeWrapperPass *DTWP = - P->getAnalysisIfAvailable<DominatorTreeWrapperPass>(); - DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr; - LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>(); - // If we have nothing to update, just return. + auto *AA = Options.AA; + auto *DT = Options.DT; + auto *LI = Options.LI; if (!DT && !LI) return NewBB; @@ -268,13 +266,13 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, if (Loop *DestLoop = LI->getLoopFor(DestBB)) { if (TIL == DestLoop) { // Both in the same loop, the NewBB joins loop. - DestLoop->addBasicBlockToLoop(NewBB, LI->getBase()); + DestLoop->addBasicBlockToLoop(NewBB, *LI); } else if (TIL->contains(DestLoop)) { // Edge from an outer loop to an inner loop. Add to the outer loop. - TIL->addBasicBlockToLoop(NewBB, LI->getBase()); + TIL->addBasicBlockToLoop(NewBB, *LI); } else if (DestLoop->contains(TIL)) { // Edge from an inner loop to an outer loop. Add to the outer loop. - DestLoop->addBasicBlockToLoop(NewBB, LI->getBase()); + DestLoop->addBasicBlockToLoop(NewBB, *LI); } else { // Edge from two loops with no containment relation. Because these // are natural loops, we know that the destination block must be the @@ -283,19 +281,20 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, assert(DestLoop->getHeader() == DestBB && "Should not create irreducible loops!"); if (Loop *P = DestLoop->getParentLoop()) - P->addBasicBlockToLoop(NewBB, LI->getBase()); + P->addBasicBlockToLoop(NewBB, *LI); } } + // If TIBB is in a loop and DestBB is outside of that loop, we may need // to update LoopSimplify form and LCSSA form. - if (!TIL->contains(DestBB) && - P->mustPreserveAnalysisID(LoopSimplifyID)) { + if (!TIL->contains(DestBB)) { assert(!TIL->contains(NewBB) && "Split point for loop exit is contained in loop!"); // Update LCSSA form in the newly created exit block. - if (P->mustPreserveAnalysisID(LCSSAID)) + if (Options.PreserveLCSSA) { createPHIsForSplitLoopExit(TIBB, NewBB, DestBB); + } // The only that we can break LoopSimplify form by splitting a critical // edge is if after the split there exists some edge from TIL to DestBB @@ -322,20 +321,12 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, if (!LoopPreds.empty()) { assert(!DestBB->isLandingPad() && "We don't split edges to landing pads!"); - BasicBlock *NewExitBB = - SplitBlockPredecessors(DestBB, LoopPreds, "split", P); - if (P->mustPreserveAnalysisID(LCSSAID)) + BasicBlock *NewExitBB = SplitBlockPredecessors( + DestBB, LoopPreds, "split", AA, DT, LI, Options.PreserveLCSSA); + if (Options.PreserveLCSSA) createPHIsForSplitLoopExit(LoopPreds, NewExitBB, DestBB); } } - // LCSSA form was updated above for the case where LoopSimplify is - // available, which means that all predecessors of loop exit blocks - // are within the loop. Without LoopSimplify form, it would be - // necessary to insert a new phi. - assert((!P->mustPreserveAnalysisID(LCSSAID) || - P->mustPreserveAnalysisID(LoopSimplifyID)) && - "SplitCriticalEdge doesn't know how to update LCCSA form " - "without LoopSimplify!"); } } |