llvm/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp

//===- LoopUnrollAnalyzer.cpp - Unrolling Effect Estimation -----*- C++ -*-===//
//
// 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 implements UnrolledInstAnalyzer class. It's used for predicting
// potential effects that loop unrolling might have, such as enabling constant
// propagation and other optimizations.
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/LoopUnrollAnalyzer.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/Operator.h"

usingnamespacellvm;

/// Try to simplify instruction \param I using its SCEV expression.
///
/// The idea is that some AddRec expressions become constants, which then
/// could trigger folding of other instructions. However, that only happens
/// for expressions whose start value is also constant, which isn't always the
/// case. In another common and important case the start value is just some
/// address (i.e. SCEVUnknown) - in this case we compute the offset and save
/// it along with the base address instead.
bool UnrolledInstAnalyzer::simplifyInstWithSCEV(Instruction *I) { … }

/// Try to simplify binary operator I.
///
/// TODO: Probably it's worth to hoist the code for estimating the
/// simplifications effects to a separate class, since we have a very similar
/// code in InlineCost already.
bool UnrolledInstAnalyzer::visitBinaryOperator(BinaryOperator &I) { … }

/// Try to fold load I.
bool UnrolledInstAnalyzer::visitLoad(LoadInst &I) { … }

/// Try to simplify cast instruction.
bool UnrolledInstAnalyzer::visitCastInst(CastInst &I) { … }

/// Try to simplify cmp instruction.
bool UnrolledInstAnalyzer::visitCmpInst(CmpInst &I) { … }

bool UnrolledInstAnalyzer::visitPHINode(PHINode &PN) { … }

bool UnrolledInstAnalyzer::visitInstruction(Instruction &I) { … }