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llvm-mirror/lib/CodeGen/TailDuplication.cpp
Hiroshi Yamauchi ae6be9df60 [PGO][PGSO] Handle MBFIWrapper
Some code gen passes use MBFIWrapper to keep track of the frequency of new
blocks. This was not taken into account and could lead to incorrect frequencies
as MBFI silently returns zero frequency for unknown/new blocks.

Add a variant for MBFIWrapper in the PGSO query interface.

Depends on D73494.
2020-01-31 09:36:55 -08:00

103 lines
3.3 KiB
C++

//===- TailDuplication.cpp - Duplicate blocks into predecessors' tails ----===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
/// \file This pass duplicates basic blocks ending in unconditional branches
/// into the tails of their predecessors, using the TailDuplicator utility
/// class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TailDuplicator.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
using namespace llvm;
#define DEBUG_TYPE "tailduplication"
namespace {
class TailDuplicateBase : public MachineFunctionPass {
TailDuplicator Duplicator;
std::unique_ptr<MBFIWrapper> MBFIW;
bool PreRegAlloc;
public:
TailDuplicateBase(char &PassID, bool PreRegAlloc)
: MachineFunctionPass(PassID), PreRegAlloc(PreRegAlloc) {}
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
AU.addRequired<ProfileSummaryInfoWrapperPass>();
MachineFunctionPass::getAnalysisUsage(AU);
}
};
class TailDuplicate : public TailDuplicateBase {
public:
static char ID;
TailDuplicate() : TailDuplicateBase(ID, false) {
initializeTailDuplicatePass(*PassRegistry::getPassRegistry());
}
};
class EarlyTailDuplicate : public TailDuplicateBase {
public:
static char ID;
EarlyTailDuplicate() : TailDuplicateBase(ID, true) {
initializeEarlyTailDuplicatePass(*PassRegistry::getPassRegistry());
}
MachineFunctionProperties getClearedProperties() const override {
return MachineFunctionProperties()
.set(MachineFunctionProperties::Property::NoPHIs);
}
};
} // end anonymous namespace
char TailDuplicate::ID;
char EarlyTailDuplicate::ID;
char &llvm::TailDuplicateID = TailDuplicate::ID;
char &llvm::EarlyTailDuplicateID = EarlyTailDuplicate::ID;
INITIALIZE_PASS(TailDuplicate, DEBUG_TYPE, "Tail Duplication", false, false)
INITIALIZE_PASS(EarlyTailDuplicate, "early-tailduplication",
"Early Tail Duplication", false, false)
bool TailDuplicateBase::runOnMachineFunction(MachineFunction &MF) {
if (skipFunction(MF.getFunction()))
return false;
auto MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
auto *PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
auto *MBFI = (PSI && PSI->hasProfileSummary()) ?
&getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI() :
nullptr;
if (MBFI)
MBFIW = std::make_unique<MBFIWrapper>(*MBFI);
Duplicator.initMF(MF, PreRegAlloc, MBPI, MBFI ? MBFIW.get() : nullptr, PSI,
/*LayoutMode=*/false);
bool MadeChange = false;
while (Duplicator.tailDuplicateBlocks())
MadeChange = true;
return MadeChange;
}