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0c2b09a9b6
Essentially, fold OrderedBasicBlock into BasicBlock, and make it auto-invalidate the instruction ordering when new instructions are added. Notably, we don't need to invalidate it when removing instructions, which is helpful when a pass mostly delete dead instructions rather than transforming them. The downside is that Instruction grows from 56 bytes to 64 bytes. The resulting LLVM code is substantially simpler and automatically handles invalidation, which makes me think that this is the right speed and size tradeoff. The important change is in SymbolTableTraitsImpl.h, where the numbering is invalidated. Everything else should be straightforward. We probably want to implement a fancier re-numbering scheme so that local updates don't invalidate the ordering, but I plan for that to be future work, maybe for someone else. Reviewed By: lattner, vsk, fhahn, dexonsmith Differential Revision: https://reviews.llvm.org/D51664
46 lines
1.9 KiB
C++
46 lines
1.9 KiB
C++
//===-- OrderedInstructions.cpp - Instruction dominance function ---------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines utility to check dominance relation of 2 instructions.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/OrderedInstructions.h"
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using namespace llvm;
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bool OrderedInstructions::localDominates(const Instruction *InstA,
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const Instruction *InstB) const {
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assert(InstA->getParent() == InstB->getParent() &&
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"Instructions must be in the same basic block");
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return InstA->comesBefore(InstB);
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}
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/// Given 2 instructions, check for dominance relation if the instructions are
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/// in the same basic block. Otherwise, use dominator tree.
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bool OrderedInstructions::dominates(const Instruction *InstA,
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const Instruction *InstB) const {
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// Use ordered basic block to do dominance check in case the 2 instructions
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// are in the same basic block.
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if (InstA->getParent() == InstB->getParent())
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return localDominates(InstA, InstB);
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return DT->dominates(InstA->getParent(), InstB->getParent());
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}
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bool OrderedInstructions::dfsBefore(const Instruction *InstA,
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const Instruction *InstB) const {
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// Use ordered basic block in case the 2 instructions are in the same basic
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// block.
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if (InstA->getParent() == InstB->getParent())
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return localDominates(InstA, InstB);
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DomTreeNode *DA = DT->getNode(InstA->getParent());
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DomTreeNode *DB = DT->getNode(InstB->getParent());
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return DA->getDFSNumIn() < DB->getDFSNumIn();
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}
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