Author: Roman Lebedev Date: 2021-01-05T01:26:36+03:00 New Revision: ed9de61cc3e280f84e3f0f98a49af21c7e59c4c9
URL: https://github.com/llvm/llvm-project/commit/ed9de61cc3e280f84e3f0f98a49af21c7e59c4c9 DIFF: https://github.com/llvm/llvm-project/commit/ed9de61cc3e280f84e3f0f98a49af21c7e59c4c9.diff LOG: [SimplifyCFGPass] mergeEmptyReturnBlocks(): switch to non-permissive DomTree updates ... which requires not inserting an edge that already exists. Added: Modified: llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp index 2c3454c46b30..c0edde8648f5 100644 --- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp +++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp @@ -77,7 +77,6 @@ STATISTIC(NumSimpl, "Number of blocks simplified"); /// If we have more than one empty (other than phi node) return blocks, /// merge them together to promote recursive block merging. -// FIXME: switch to non-permissive DomTreeUpdater::applyUpdates(). static bool mergeEmptyReturnBlocks(Function &F, DomTreeUpdater *DTU) { bool Changed = false; @@ -143,7 +142,10 @@ static bool mergeEmptyReturnBlocks(Function &F, DomTreeUpdater *DTU) { if (DTU) { for (auto *Predecessor : predecessors(&BB)) { Updates.push_back({DominatorTree::Delete, Predecessor, &BB}); - Updates.push_back({DominatorTree::Insert, Predecessor, RetBlock}); + // But, iff Predecessor already branches to RetBlock, + // don't (re-)add DomTree edge, because it already exists. + if (!is_contained(successors(Predecessor), RetBlock)) + Updates.push_back({DominatorTree::Insert, Predecessor, RetBlock}); } } BB.replaceAllUsesWith(RetBlock); @@ -176,7 +178,7 @@ static bool mergeEmptyReturnBlocks(Function &F, DomTreeUpdater *DTU) { } if (DTU) { - DTU->applyUpdatesPermissive(Updates); + DTU->applyUpdates(Updates); for (auto *BB : DeadBlocks) DTU->deleteBB(BB); } else { _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
