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llvm-mirror/lib/Analysis/OrderedInstructions.cpp
Max Kazantsev 12bc747451 [NFC] Move OrderedInstructions and InstructionPrecedenceTracking to Analysis
These classes don't make any changes to IR and have no reason to be in
Transform/Utils. This patch moves them to Analysis folder. This will allow
us reusing these classes in some analyzes, like MustExecute.

llvm-svn: 341015
2018-08-30 04:49:03 +00:00

52 lines
2.0 KiB
C++

//===-- OrderedInstructions.cpp - Instruction dominance function ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines utility to check dominance relation of 2 instructions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/OrderedInstructions.h"
using namespace llvm;
bool OrderedInstructions::localDominates(const Instruction *InstA,
const Instruction *InstB) const {
assert(InstA->getParent() == InstB->getParent() &&
"Instructions must be in the same basic block");
const BasicBlock *IBB = InstA->getParent();
auto OBB = OBBMap.find(IBB);
if (OBB == OBBMap.end())
OBB = OBBMap.insert({IBB, make_unique<OrderedBasicBlock>(IBB)}).first;
return OBB->second->dominates(InstA, InstB);
}
/// Given 2 instructions, use OrderedBasicBlock to check for dominance relation
/// if the instructions are in the same basic block, Otherwise, use dominator
/// tree.
bool OrderedInstructions::dominates(const Instruction *InstA,
const Instruction *InstB) const {
// Use ordered basic block to do dominance check in case the 2 instructions
// are in the same basic block.
if (InstA->getParent() == InstB->getParent())
return localDominates(InstA, InstB);
return DT->dominates(InstA->getParent(), InstB->getParent());
}
bool OrderedInstructions::dfsBefore(const Instruction *InstA,
const Instruction *InstB) const {
// Use ordered basic block in case the 2 instructions are in the same basic
// block.
if (InstA->getParent() == InstB->getParent())
return localDominates(InstA, InstB);
DomTreeNode *DA = DT->getNode(InstA->getParent());
DomTreeNode *DB = DT->getNode(InstB->getParent());
return DA->getDFSNumIn() < DB->getDFSNumIn();
}