diff options
| -rw-r--r-- | include/llvm/CodeGen/MachineBranchProbabilityInfo.h | 1 | ||||
| -rw-r--r-- | lib/CodeGen/MachineBranchProbabilityInfo.cpp | 14 |
2 files changed, 4 insertions, 11 deletions
diff --git a/include/llvm/CodeGen/MachineBranchProbabilityInfo.h b/include/llvm/CodeGen/MachineBranchProbabilityInfo.h index 943901f59f..994e1eec23 100644 --- a/include/llvm/CodeGen/MachineBranchProbabilityInfo.h +++ b/include/llvm/CodeGen/MachineBranchProbabilityInfo.h @@ -59,6 +59,7 @@ public: bool isEdgeHot(MachineBasicBlock *Src, MachineBasicBlock *Dst) const; // Return a hot successor for the block BB or null if there isn't one. + // NB: This routine's complexity is linear on the number of successors. MachineBasicBlock *getHotSucc(MachineBasicBlock *MBB) const; // Return a probability as a fraction between 0 (0% probability) and diff --git a/lib/CodeGen/MachineBranchProbabilityInfo.cpp b/lib/CodeGen/MachineBranchProbabilityInfo.cpp index 0037d52515..e3cfa9ea5a 100644 --- a/lib/CodeGen/MachineBranchProbabilityInfo.cpp +++ b/lib/CodeGen/MachineBranchProbabilityInfo.cpp @@ -76,26 +76,18 @@ bool MachineBranchProbabilityInfo::isEdgeHot(MachineBasicBlock *Src, MachineBasicBlock * MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const { - uint32_t Sum = 0; uint32_t MaxWeight = 0; MachineBasicBlock *MaxSucc = 0; - for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - MachineBasicBlock *Succ = *I; - uint32_t Weight = getEdgeWeight(MBB, Succ); - uint32_t PrevSum = Sum; - - Sum += Weight; - assert(Sum > PrevSum); (void) PrevSum; - + uint32_t Weight = getEdgeWeight(MBB, *I); if (Weight > MaxWeight) { MaxWeight = Weight; - MaxSucc = Succ; + MaxSucc = *I; } } - if (BranchProbability(MaxWeight, Sum) >= BranchProbability(4, 5)) + if (getEdgeProbability(MBB, MaxSucc) >= BranchProbability(4, 5)) return MaxSucc; return 0; |