llvm/llvm/lib/Transforms/Utils/LoopVersioning.cpp

//===- LoopVersioning.cpp - Utility to version a loop ---------------------===//
//
// 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 file defines a utility class to perform loop versioning.  The versioned
// loop speculates that otherwise may-aliasing memory accesses don't overlap and
// emits checks to prove this.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/LoopVersioning.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/InstSimplifyFolder.h"
#include "llvm/Analysis/LoopAccessAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"

usingnamespacellvm;

#define DEBUG_TYPE …

static cl::opt<bool>
    AnnotateNoAlias("loop-version-annotate-no-alias", cl::init(true),
                    cl::Hidden,
                    cl::desc("Add no-alias annotation for instructions that "
                             "are disambiguated by memchecks"));

LoopVersioning::LoopVersioning(const LoopAccessInfo &LAI,
                               ArrayRef<RuntimePointerCheck> Checks, Loop *L,
                               LoopInfo *LI, DominatorTree *DT,
                               ScalarEvolution *SE)
    : … { … }

void LoopVersioning::versionLoop(
    const SmallVectorImpl<Instruction *> &DefsUsedOutside) { … }

void LoopVersioning::addPHINodes(
    const SmallVectorImpl<Instruction *> &DefsUsedOutside) { … }

void LoopVersioning::prepareNoAliasMetadata() { … }

void LoopVersioning::annotateLoopWithNoAlias() { … }

void LoopVersioning::annotateInstWithNoAlias(Instruction *VersionedInst,
                                             const Instruction *OrigInst) { … }

namespace {
bool runImpl(LoopInfo *LI, LoopAccessInfoManager &LAIs, DominatorTree *DT,
             ScalarEvolution *SE) { … }
}

PreservedAnalyses LoopVersioningPass::run(Function &F,
                                          FunctionAnalysisManager &AM) { … }