Author: Roman Lebedev Date: 2020-12-20T00:18:36+03:00 New Revision: 262ff9c23e72643ba02db6166b6ca942ef067dc9
URL: https://github.com/llvm/llvm-project/commit/262ff9c23e72643ba02db6166b6ca942ef067dc9 DIFF: https://github.com/llvm/llvm-project/commit/262ff9c23e72643ba02db6166b6ca942ef067dc9.diff LOG: [SimplifyCFG] Teach TryToMergeLandingPad() to preserve DomTree Added: Modified: llvm/lib/Transforms/Utils/SimplifyCFG.cpp llvm/test/Transforms/SimplifyCFG/duplicate-landingpad.ll Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 3bc09978489e..c2557165a0ba 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -6082,7 +6082,7 @@ bool SimplifyCFGOpt::simplifyIndirectBr(IndirectBrInst *IBI) { /// block when the inputs in the phi are the same for the two blocks being /// merged. In some cases, this could result in removal of the PHI entirely. static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI, - BasicBlock *BB) { + BasicBlock *BB, DomTreeUpdater *DTU) { auto Succ = BB->getUniqueSuccessor(); assert(Succ); // If there's a phi in the successor block, we'd likely have to introduce @@ -6103,6 +6103,8 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI, if (!BI2 || !BI2->isIdenticalTo(BI)) continue; + std::vector<DominatorTree::UpdateType> Updates; + // We've found an identical block. Update our predecessors to take that // path instead and make ourselves dead. SmallPtrSet<BasicBlock *, 16> Preds; @@ -6112,6 +6114,8 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI, assert(II->getNormalDest() != BB && II->getUnwindDest() == BB && "unexpected successor"); II->setUnwindDest(OtherPred); + Updates.push_back({DominatorTree::Delete, Pred, BB}); + Updates.push_back({DominatorTree::Insert, Pred, OtherPred}); } // The debug info in OtherPred doesn't cover the merged control flow that @@ -6127,11 +6131,14 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI, Succs.insert(succ_begin(BB), succ_end(BB)); for (BasicBlock *Succ : Succs) { Succ->removePredecessor(BB); + Updates.push_back({DominatorTree::Delete, BB, Succ}); } IRBuilder<> Builder(BI); Builder.CreateUnreachable(); BI->eraseFromParent(); + if (DTU) + DTU->applyUpdatesPermissive(Updates); return true; } return false; @@ -6179,7 +6186,7 @@ bool SimplifyCFGOpt::simplifyUncondBranch(BranchInst *BI, if (LandingPadInst *LPad = dyn_cast<LandingPadInst>(I)) { for (++I; isa<DbgInfoIntrinsic>(I); ++I) ; - if (I->isTerminator() && TryToMergeLandingPad(LPad, BI, BB)) + if (I->isTerminator() && TryToMergeLandingPad(LPad, BI, BB, DTU)) return true; } diff --git a/llvm/test/Transforms/SimplifyCFG/duplicate-landingpad.ll b/llvm/test/Transforms/SimplifyCFG/duplicate-landingpad.ll index 6f8b069810f8..a38f0ae6275c 100644 --- a/llvm/test/Transforms/SimplifyCFG/duplicate-landingpad.ll +++ b/llvm/test/Transforms/SimplifyCFG/duplicate-landingpad.ll @@ -1,5 +1,5 @@ ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py -; RUN: opt < %s -simplifycfg -S | FileCheck %s +; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" declare i32 @__gxx_personality_v0(...) _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
