Author: Roman Lebedev Date: 2021-01-22T17:23:10+03:00 New Revision: aabed3718ae25476c0f6b7e70c83ba4658f00e5c
URL: https://github.com/llvm/llvm-project/commit/aabed3718ae25476c0f6b7e70c83ba4658f00e5c DIFF: https://github.com/llvm/llvm-project/commit/aabed3718ae25476c0f6b7e70c83ba4658f00e5c.diff LOG: [NFCI-ish][SimplifyCFG] FoldBranchToCommonDest(): really don't deal with uncond branches While we already ignore uncond branches, we could still potentially end up with a conditional branches with identical destinations due to the visitation order, or because we were called as an utility. But if we have such a disguised uncond branch, we still probably shouldn't deal with it here. 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 d0028c013fa3..5ca8a0b33176 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2775,7 +2775,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, DomTreeUpdater *DTU, unsigned BonusInstThreshold) { // If this block ends with an unconditional branch, // let SpeculativelyExecuteBB() deal with it. - if (!BI->isConditional()) + if (!BI->isConditional() || is_splat(successors(BI))) return false; BasicBlock *BB = BI->getParent(); @@ -2863,7 +2863,8 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, DomTreeUpdater *DTU, // Check that we have two conditional branches. If there is a PHI node in // the common successor, verify that the same value flows in from both // blocks. - if (!PBI || PBI->isUnconditional() || !SafeToMergeTerminators(BI, PBI)) + if (!PBI || PBI->isUnconditional() || is_splat(successors(PBI)) || + !SafeToMergeTerminators(BI, PBI)) continue; // Determine if the two branches share a common destination. _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
