diff options
Diffstat (limited to 'include/llvm/CodeGen/MachineBranchProbabilityInfo.h')
| -rw-r--r-- | include/llvm/CodeGen/MachineBranchProbabilityInfo.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/include/llvm/CodeGen/MachineBranchProbabilityInfo.h b/include/llvm/CodeGen/MachineBranchProbabilityInfo.h index d9673e2..e768874 100644 --- a/include/llvm/CodeGen/MachineBranchProbabilityInfo.h +++ b/include/llvm/CodeGen/MachineBranchProbabilityInfo.h @@ -34,9 +34,6 @@ class MachineBranchProbabilityInfo : public ImmutablePass { // weight to just "inherit" the non-zero weight of an adjacent successor. static const uint32_t DEFAULT_WEIGHT = 16; - // Get sum of the block successors' weights. - uint32_t getSumForBlock(MachineBasicBlock *MBB) const; - public: static char ID; @@ -53,15 +50,24 @@ public: // DEFAULT_WEIGHT. uint32_t getEdgeWeight(MachineBasicBlock *Src, MachineBasicBlock *Dst) const; + // Get sum of the block successors' weights, potentially scaling them to fit + // within 32-bits. If scaling is required, sets Scale based on the necessary + // adjustment. Any edge weights used with the sum should be divided by Scale. + uint32_t getSumForBlock(MachineBasicBlock *MBB, uint32_t &Scale) const; + // A 'Hot' edge is an edge which probability is >= 80%. 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 // 1 (100% probability), however the value is never equal to 0, and can be 1 // only iff SRC block has only one successor. + // NB: This routine's complexity is linear on the number of successors of + // Src. Querying sequentially for each successor's probability is a quadratic + // query pattern. BranchProbability getEdgeProbability(MachineBasicBlock *Src, MachineBasicBlock *Dst) const; |