llvm/llvm/lib/Transforms/Scalar/Sink.cpp

//===-- Sink.cpp - Code Sinking -------------------------------------------===//
//
// 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 moves instructions into successor blocks, when possible, so that
// they aren't executed on paths where their results aren't needed.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Scalar/Sink.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.h"
usingnamespacellvm;

#define DEBUG_TYPE …

STATISTIC(NumSunk, "Number of instructions sunk");
STATISTIC(NumSinkIter, "Number of sinking iterations");

static bool isSafeToMove(Instruction *Inst, AliasAnalysis &AA,
                         SmallPtrSetImpl<Instruction *> &Stores) { … }

/// IsAcceptableTarget - Return true if it is possible to sink the instruction
/// in the specified basic block.
static bool IsAcceptableTarget(Instruction *Inst, BasicBlock *SuccToSinkTo,
                               DominatorTree &DT, LoopInfo &LI) { … }

/// SinkInstruction - Determine whether it is safe to sink the specified machine
/// instruction out of its current block into a successor.
static bool SinkInstruction(Instruction *Inst,
                            SmallPtrSetImpl<Instruction *> &Stores,
                            DominatorTree &DT, LoopInfo &LI, AAResults &AA) { … }

static bool ProcessBlock(BasicBlock &BB, DominatorTree &DT, LoopInfo &LI,
                         AAResults &AA) { … }

static bool iterativelySinkInstructions(Function &F, DominatorTree &DT,
                                        LoopInfo &LI, AAResults &AA) { … }

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

namespace {
  class SinkingLegacyPass : public FunctionPass { … };
} // end anonymous namespace

char SinkingLegacyPass::ID = …;
INITIALIZE_PASS_BEGIN(SinkingLegacyPass, "sink", "Code sinking", false, false)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_END(SinkingLegacyPass, "sink", "Code sinking", false, false)

FunctionPass *llvm::createSinkingPass() { … }