Author: Roman Lebedev Date: 2021-01-05T01:26:37+03:00 New Revision: 32c47ebef18d904445ce909e4a6922ffbfe4053f
URL: https://github.com/llvm/llvm-project/commit/32c47ebef18d904445ce909e4a6922ffbfe4053f DIFF: https://github.com/llvm/llvm-project/commit/32c47ebef18d904445ce909e4a6922ffbfe4053f.diff LOG: [SimplifyCFG] SimplifyCondBranchToTwoReturns(): switch to non-permissive DomTree updates ... which requires not deleting an edge that just got deleted, because we could be dealing with a block that didn't go through ConstantFoldTerminator() yet, and thus has a degenerate cond br with matching true/false destinations. Added: Modified: llvm/lib/Transforms/Utils/SimplifyCFG.cpp Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index a61e48d84f01..9f808278d899 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2674,13 +2674,13 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, /// If we found a conditional branch that goes to two returning blocks, /// try to merge them together into one return, /// introducing a select if the return values disagree. -// FIXME: switch to non-permissive DomTreeUpdater::applyUpdates(). bool SimplifyCFGOpt::SimplifyCondBranchToTwoReturns(BranchInst *BI, IRBuilder<> &Builder) { auto *BB = BI->getParent(); assert(BI->isConditional() && "Must be a conditional branch"); BasicBlock *TrueSucc = BI->getSuccessor(0); BasicBlock *FalseSucc = BI->getSuccessor(1); + // NOTE: destinations may match, this could be degenerate uncond branch. ReturnInst *TrueRet = cast<ReturnInst>(TrueSucc->getTerminator()); ReturnInst *FalseRet = cast<ReturnInst>(FalseSucc->getTerminator()); @@ -2702,8 +2702,11 @@ bool SimplifyCFGOpt::SimplifyCondBranchToTwoReturns(BranchInst *BI, Builder.CreateRetVoid(); EraseTerminatorAndDCECond(BI); if (DTU) { - DTU->applyUpdatesPermissive({{DominatorTree::Delete, BB, TrueSucc}, - {DominatorTree::Delete, BB, FalseSucc}}); + SmallVector<DominatorTree::UpdateType, 2> Updates; + Updates.push_back({DominatorTree::Delete, BB, TrueSucc}); + if (TrueSucc != FalseSucc) + Updates.push_back({DominatorTree::Delete, BB, FalseSucc}); + DTU->applyUpdates(Updates); } return true; } @@ -2761,10 +2764,12 @@ bool SimplifyCFGOpt::SimplifyCondBranchToTwoReturns(BranchInst *BI, << *TrueSucc << "\nFALSEBLOCK: " << *FalseSucc); EraseTerminatorAndDCECond(BI); - if (DTU) { - DTU->applyUpdatesPermissive({{DominatorTree::Delete, BB, TrueSucc}, - {DominatorTree::Delete, BB, FalseSucc}}); + SmallVector<DominatorTree::UpdateType, 2> Updates; + Updates.push_back({DominatorTree::Delete, BB, TrueSucc}); + if (TrueSucc != FalseSucc) + Updates.push_back({DominatorTree::Delete, BB, FalseSucc}); + DTU->applyUpdates(Updates); } return true; _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
