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llvm-mirror/include/llvm/Analysis/OrderedInstructions.h
Chandler Carruth ae65e281f3 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.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

65 lines
2.4 KiB
C++

//===- llvm/Transforms/Utils/OrderedInstructions.h -------------*- 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 an efficient way to check for dominance relation between 2
// instructions.
//
// This interface dispatches to appropriate dominance check given 2
// instructions, i.e. in case the instructions are in the same basic block,
// OrderedBasicBlock (with instruction numbering and caching) are used.
// Otherwise, dominator tree is used.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_ORDEREDINSTRUCTIONS_H
#define LLVM_ANALYSIS_ORDEREDINSTRUCTIONS_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/Analysis/OrderedBasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Operator.h"
namespace llvm {
class OrderedInstructions {
/// Used to check dominance for instructions in same basic block.
mutable DenseMap<const BasicBlock *, std::unique_ptr<OrderedBasicBlock>>
OBBMap;
/// The dominator tree of the parent function.
DominatorTree *DT;
/// Return true if the first instruction comes before the second in the
/// same basic block. It will create an ordered basic block, if it does
/// not yet exist in OBBMap.
bool localDominates(const Instruction *, const Instruction *) const;
public:
/// Constructor.
OrderedInstructions(DominatorTree *DT) : DT(DT) {}
/// Return true if first instruction dominates the second.
bool dominates(const Instruction *, const Instruction *) const;
/// Return true if the first instruction comes before the second in the
/// dominator tree DFS traversal if they are in different basic blocks,
/// or if the first instruction comes before the second in the same basic
/// block.
bool dfsBefore(const Instruction *, const Instruction *) const;
/// Invalidate the OrderedBasicBlock cache when its basic block changes.
/// i.e. If an instruction is deleted or added to the basic block, the user
/// should call this function to invalidate the OrderedBasicBlock cache for
/// this basic block.
void invalidateBlock(const BasicBlock *BB) { OBBMap.erase(BB); }
};
} // end namespace llvm
#endif // LLVM_ANALYSIS_ORDEREDINSTRUCTIONS_H