From b197d5b0a00747c0b6d8f82a275f871f3c9240c2 Mon Sep 17 00:00:00 2001 From: Dehao Chen Date: Thu, 23 Mar 2017 23:28:09 +0000 Subject: Fix trellis layout to avoid mis-identify triangle. Summary: For the following CFG: A->B B->C A->C If there is another edge B->D, then ABC should not be considered as triangle. Reviewers: davidxl, iteratee Reviewed By: iteratee Subscribers: nemanjai, llvm-commits Differential Revision: https://reviews.llvm.org/D31310 llvm-svn: 298661 --- llvm/lib/CodeGen/MachineBlockPlacement.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen/MachineBlockPlacement.cpp') diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp index d3bf95b9a95..de0b572f2fe 100644 --- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp +++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp @@ -839,8 +839,13 @@ bool MachineBlockPlacement::isTrellis( int PredCount = 0; for (auto SuccPred : Succ->predecessors()) { // Allow triangle successors, but don't count them. - if (Successors.count(SuccPred)) + if (Successors.count(SuccPred)) { + // Make sure that it is actually a triangle. + for (MachineBasicBlock *CheckSucc : SuccPred->successors()) + if (!Successors.count(CheckSucc)) + return false; continue; + } const BlockChain *PredChain = BlockToChain[SuccPred]; if (SuccPred == BB || (BlockFilter && !BlockFilter->count(SuccPred)) || PredChain == &Chain || PredChain == BlockToChain[Succ]) -- cgit v1.2.3