diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp index fd417055f9c..55cf20a2936 100644 --- a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp +++ b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp @@ -596,6 +596,10 @@ public: return true; } + + bool foldingBreaksCurrentLoop() const { + return DeleteCurrentLoop; + } }; } // namespace @@ -603,7 +607,8 @@ public: /// branches. static bool constantFoldTerminators(Loop &L, DominatorTree &DT, LoopInfo &LI, ScalarEvolution &SE, - MemorySSAUpdater *MSSAU) { + MemorySSAUpdater *MSSAU, + bool &IsLoopDeleted) { if (!EnableTermFolding) return false; @@ -613,7 +618,9 @@ static bool constantFoldTerminators(Loop &L, DominatorTree &DT, LoopInfo &LI, return false; ConstantTerminatorFoldingImpl BranchFolder(L, LI, DT, SE, MSSAU); - return BranchFolder.run(); + bool Changed = BranchFolder.run(); + IsLoopDeleted = Changed && BranchFolder.foldingBreaksCurrentLoop(); + return Changed; } static bool mergeBlocksIntoPredecessors(Loop &L, DominatorTree &DT, @@ -645,11 +652,15 @@ static bool mergeBlocksIntoPredecessors(Loop &L, DominatorTree &DT, } static bool simplifyLoopCFG(Loop &L, DominatorTree &DT, LoopInfo &LI, - ScalarEvolution &SE, MemorySSAUpdater *MSSAU) { + ScalarEvolution &SE, MemorySSAUpdater *MSSAU, + bool &isLoopDeleted) { bool Changed = false; // Constant-fold terminators with known constant conditions. - Changed |= constantFoldTerminators(L, DT, LI, SE, MSSAU); + Changed |= constantFoldTerminators(L, DT, LI, SE, MSSAU, isLoopDeleted); + + if (isLoopDeleted) + return true; // Eliminate unconditional branches by merging blocks into their predecessors. Changed |= mergeBlocksIntoPredecessors(L, DT, LI, MSSAU); @@ -662,14 +673,19 @@ static bool simplifyLoopCFG(Loop &L, DominatorTree &DT, LoopInfo &LI, PreservedAnalyses LoopSimplifyCFGPass::run(Loop &L, LoopAnalysisManager &AM, LoopStandardAnalysisResults &AR, - LPMUpdater &) { + LPMUpdater &LPMU) { Optional<MemorySSAUpdater> MSSAU; if (EnableMSSALoopDependency && AR.MSSA) MSSAU = MemorySSAUpdater(AR.MSSA); + bool DeleteCurrentLoop = false; if (!simplifyLoopCFG(L, AR.DT, AR.LI, AR.SE, - MSSAU.hasValue() ? MSSAU.getPointer() : nullptr)) + MSSAU.hasValue() ? MSSAU.getPointer() : nullptr, + DeleteCurrentLoop)) return PreservedAnalyses::all(); + if (DeleteCurrentLoop) + LPMU.markLoopAsDeleted(L, "loop-simplifycfg"); + return getLoopPassPreservedAnalyses(); } @@ -681,7 +697,7 @@ public: initializeLoopSimplifyCFGLegacyPassPass(*PassRegistry::getPassRegistry()); } - bool runOnLoop(Loop *L, LPPassManager &) override { + bool runOnLoop(Loop *L, LPPassManager &LPM) override { if (skipLoop(L)) return false; @@ -695,8 +711,13 @@ public: if (VerifyMemorySSA) MSSA->verifyMemorySSA(); } - return simplifyLoopCFG(*L, DT, LI, SE, - MSSAU.hasValue() ? MSSAU.getPointer() : nullptr); + bool DeleteCurrentLoop = false; + bool Changed = simplifyLoopCFG( + *L, DT, LI, SE, MSSAU.hasValue() ? MSSAU.getPointer() : nullptr, + DeleteCurrentLoop); + if (DeleteCurrentLoop) + LPM.markLoopAsDeleted(*L); + return Changed; } void getAnalysisUsage(AnalysisUsage &AU) const override { |
