e8e8552692
Now that successor iterators are Use iterators, it is no longer cheap to get the successor index. Replace uses with the variant that takes the successor index, which in all cases is easily available. This is primarily cleanup after the somewhat recent successor changes. There's also a minor (barely measurable) performance improvement here.
104 lines
3.8 KiB
C++
104 lines
3.8 KiB
C++
//===- MachineBranchProbabilityInfo.cpp - Machine Branch Probability Info -===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This analysis uses probability info stored in Machine Basic Blocks.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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INITIALIZE_PASS(MachineBranchProbabilityInfoWrapperPass, "machine-branch-prob",
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"Machine Branch Probability Analysis", false, true)
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namespace llvm {
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cl::opt<unsigned>
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StaticLikelyProb("static-likely-prob",
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cl::desc("branch probability threshold in percentage"
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" to be considered very likely"),
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cl::init(80), cl::Hidden);
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cl::opt<unsigned> ProfileLikelyProb(
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"profile-likely-prob",
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cl::desc("branch probability threshold in percentage to be considered"
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" very likely when profile is available"),
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cl::init(51), cl::Hidden);
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} // namespace llvm
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MachineBranchProbabilityAnalysis::Result
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MachineBranchProbabilityAnalysis::run(MachineFunction &,
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MachineFunctionAnalysisManager &) {
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return MachineBranchProbabilityInfo();
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}
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PreservedAnalyses
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MachineBranchProbabilityPrinterPass::run(MachineFunction &MF,
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MachineFunctionAnalysisManager &MFAM) {
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OS << "Printing analysis 'Machine Branch Probability Analysis' for machine "
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"function '"
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<< MF.getName() << "':\n";
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auto &MBPI = MFAM.getResult<MachineBranchProbabilityAnalysis>(MF);
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for (const MachineBasicBlock &MBB : MF) {
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for (const MachineBasicBlock *Succ : MBB.successors())
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MBPI.printEdgeProbability(OS << " ", &MBB, Succ);
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}
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return PreservedAnalyses::all();
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}
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char MachineBranchProbabilityInfoWrapperPass::ID = 0;
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MachineBranchProbabilityInfoWrapperPass::
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MachineBranchProbabilityInfoWrapperPass()
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: ImmutablePass(ID) {}
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void MachineBranchProbabilityInfoWrapperPass::anchor() {}
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AnalysisKey MachineBranchProbabilityAnalysis::Key;
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bool MachineBranchProbabilityInfo::invalidate(
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MachineFunction &, const PreservedAnalyses &PA,
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MachineFunctionAnalysisManager::Invalidator &) {
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auto PAC = PA.getChecker<MachineBranchProbabilityAnalysis>();
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return !PAC.preservedWhenStateless();
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}
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BranchProbability
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MachineBranchProbabilityInfo::getEdgeProbability(const MachineBasicBlock *Src,
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unsigned SuccIdx) const {
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return Src->getSuccProbability(Src->succ_begin() + SuccIdx);
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}
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BranchProbability MachineBranchProbabilityInfo::getEdgeProbability(
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const MachineBasicBlock *Src, const MachineBasicBlock *Dst) const {
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// This is a linear search. Try to use the const_succ_iterator version when
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// possible.
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return Src->getSuccProbability(find(Src->successors(), Dst));
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}
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bool MachineBranchProbabilityInfo::isEdgeHot(
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const MachineBasicBlock *Src, const MachineBasicBlock *Dst) const {
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BranchProbability HotProb(StaticLikelyProb, 100);
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return getEdgeProbability(Src, Dst) > HotProb;
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}
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raw_ostream &MachineBranchProbabilityInfo::printEdgeProbability(
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raw_ostream &OS, const MachineBasicBlock *Src,
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const MachineBasicBlock *Dst) const {
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const BranchProbability Prob = getEdgeProbability(Src, Dst);
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OS << "edge " << printMBBReference(*Src) << " -> " << printMBBReference(*Dst)
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<< " probability is " << Prob
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<< (isEdgeHot(Src, Dst) ? " [HOT edge]\n" : "\n");
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return OS;
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}
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