From 1ccca9e6731d9b18c5901abd0ebc0b5d5f71d84a Mon Sep 17 00:00:00 2001 From: Cong Hou Date: Tue, 1 Dec 2015 00:55:42 +0000 Subject: Fix a bug in MachineBlockPlacement that may cause assertion failure during BranchProbability construction. The root cause is the rounding behavior in BranchProbability construction. We may consider to use truncation instead in the future. llvm-svn: 254356 --- llvm/lib/CodeGen/MachineBlockPlacement.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/MachineBlockPlacement.cpp b/llvm/lib/CodeGen/MachineBlockPlacement.cpp index ddddd483e80..fcddf346cf6 100644 --- a/llvm/lib/CodeGen/MachineBlockPlacement.cpp +++ b/llvm/lib/CodeGen/MachineBlockPlacement.cpp @@ -423,9 +423,13 @@ MachineBlockPlacement::selectBestSuccessor(MachineBasicBlock *BB, DEBUG(dbgs() << "Attempting merge from: " << getBlockName(BB) << "\n"); for (MachineBasicBlock *Succ : Successors) { - BranchProbability SuccProb( - MBPI->getEdgeProbability(BB, Succ).getNumerator(), - AdjustedSumProb.getNumerator()); + BranchProbability SuccProb; + uint32_t SuccProbN = MBPI->getEdgeProbability(BB, Succ).getNumerator(); + uint32_t SuccProbD = AdjustedSumProb.getNumerator(); + if (SuccProbN >= SuccProbD) + SuccProb = BranchProbability::getOne(); + else + SuccProb = BranchProbability(SuccProbN, SuccProbD); // If we outline optional branches, look whether Succ is unavoidable, i.e. // dominates all terminators of the MachineFunction. If it does, other -- cgit v1.2.3