mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-26 04:32:44 +01:00
70 lines
2.5 KiB
C++
70 lines
2.5 KiB
C++
//=- MachineBranchProbabilityInfo.h - Branch Probability Analysis -*- C++ -*-=//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This pass is used to evaluate branch probabilties on machine basic blocks.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H
|
|
#define LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H
|
|
|
|
#include "llvm/CodeGen/MachineBasicBlock.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Support/BranchProbability.h"
|
|
#include <climits>
|
|
#include <numeric>
|
|
|
|
namespace llvm {
|
|
|
|
class MachineBranchProbabilityInfo : public ImmutablePass {
|
|
virtual void anchor();
|
|
|
|
// Default weight value. Used when we don't have information about the edge.
|
|
// TODO: DEFAULT_WEIGHT makes sense during static predication, when none of
|
|
// the successors have a weight yet. But it doesn't make sense when providing
|
|
// weight to an edge that may have siblings with non-zero weights. This can
|
|
// be handled various ways, but it's probably fine for an edge with unknown
|
|
// weight to just "inherit" the non-zero weight of an adjacent successor.
|
|
static const uint32_t DEFAULT_WEIGHT = 16;
|
|
|
|
public:
|
|
static char ID;
|
|
|
|
MachineBranchProbabilityInfo();
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
// Return edge probability.
|
|
BranchProbability getEdgeProbability(const MachineBasicBlock *Src,
|
|
const MachineBasicBlock *Dst) const;
|
|
|
|
// Same as above, but using a const_succ_iterator from Src. This is faster
|
|
// when the iterator is already available.
|
|
BranchProbability
|
|
getEdgeProbability(const MachineBasicBlock *Src,
|
|
MachineBasicBlock::const_succ_iterator Dst) const;
|
|
|
|
// A 'Hot' edge is an edge which probability is >= 80%.
|
|
bool isEdgeHot(const MachineBasicBlock *Src,
|
|
const MachineBasicBlock *Dst) const;
|
|
|
|
// Print value 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.
|
|
raw_ostream &printEdgeProbability(raw_ostream &OS,
|
|
const MachineBasicBlock *Src,
|
|
const MachineBasicBlock *Dst) const;
|
|
};
|
|
|
|
}
|
|
|
|
|
|
#endif
|