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archived-llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h
Chandler Carruth 6b547686c5 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-19 08:50:56 +00:00

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//===-- llvm/Transforms/Utils/SimplifyIndVar.h - Indvar Utils ---*- 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 defines in interface for induction variable simplification. It does
// not define any actual pass or policy, but provides a single function to
// simplify a loop's induction variables based on ScalarEvolution.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
#define LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
#include "llvm/IR/ValueHandle.h"
namespace llvm {
class CastInst;
class DominatorTree;
class Loop;
class LoopInfo;
class PHINode;
class ScalarEvolution;
class SCEVExpander;
/// Interface for visiting interesting IV users that are recognized but not
/// simplified by this utility.
class IVVisitor {
protected:
const DominatorTree *DT = nullptr;
virtual void anchor();
public:
IVVisitor() = default;
virtual ~IVVisitor() = default;
const DominatorTree *getDomTree() const { return DT; }
virtual void visitCast(CastInst *Cast) = 0;
};
/// simplifyUsersOfIV - Simplify instructions that use this induction variable
/// by using ScalarEvolution to analyze the IV's recurrence.
bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, SmallVectorImpl<WeakTrackingVH> &Dead,
SCEVExpander &Rewriter, IVVisitor *V = nullptr);
/// SimplifyLoopIVs - Simplify users of induction variables within this
/// loop. This does not actually change or add IVs.
bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
LoopInfo *LI, SmallVectorImpl<WeakTrackingVH> &Dead);
} // end namespace llvm
#endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H