mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-25 20:23:11 +01:00
d24cdaa414
This patch removes all getEdgeWeight() interfaces from CodeGen directory. As getEdgeProbability() is a little more expensive than getEdgeWeight(), I will compose a patch soon in which BPI only stores probabilities instead of edge weights so that getEdgeProbability() will have O(1) time. Differential revision: http://reviews.llvm.org/D15489 llvm-svn: 256039
78 lines
2.8 KiB
C++
78 lines
2.8 KiB
C++
//=- MachineBranchProbabilityInfo.h - Branch Probability Analysis -*- C++ -*-=//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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() : ImmutablePass(ID) {
|
|
PassRegistry &Registry = *PassRegistry::getPassRegistry();
|
|
initializeMachineBranchProbabilityInfoPass(Registry);
|
|
}
|
|
|
|
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;
|
|
|
|
// 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;
|
|
|
|
// 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
|