diff options
| -rw-r--r-- | llvm/lib/CodeGen/MachineBasicBlock.cpp | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp index c9c6a9d6246..de91f0db75a 100644 --- a/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -510,13 +510,8 @@ void MachineBasicBlock::addSuccessor(MachineBasicBlock *Succ, BranchProbability Prob) { // Probability list is either empty (if successor list isn't empty, this means // disabled optimization) or has the same size as successor list. - if (!(Probs.empty() && !Successors.empty())) { - assert((Probs.empty() || (Prob.isUnknown() && Probs.back().isUnknown()) || - (!Prob.isUnknown() && !Probs.back().isUnknown())) && - "Successors with both known and unknwon probabilities are not " - "allowed."); + if (!(Probs.empty() && !Successors.empty())) Probs.push_back(Prob); - } Successors.push_back(Succ); Succ->addPredecessor(this); } @@ -1116,10 +1111,24 @@ MachineBasicBlock::findDebugLoc(instr_iterator MBBI) { /// Return probability of the edge from this block to MBB. BranchProbability MachineBasicBlock::getSuccProbability(const_succ_iterator Succ) const { - if (Probs.empty() || Probs.back().isUnknown()) + if (Probs.empty()) return BranchProbability(1, succ_size()); - return *getProbabilityIterator(Succ); + const auto &Prob = *getProbabilityIterator(Succ); + if (Prob.isUnknown()) { + // For unknown probabilities, collect the sum of all known ones, and evenly + // ditribute the complemental of the sum to each unknown probability. + unsigned KnownProbNum = 0; + auto Sum = BranchProbability::getZero(); + for (auto &P : Probs) { + if (!P.isUnknown()) { + Sum += P; + KnownProbNum++; + } + } + return Sum.getCompl() / (Probs.size() - KnownProbNum); + } else + return Prob; } /// Set successor probability of a given iterator. |
