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7896c9f436
Patch by Howard Hinnant! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
74 lines
2.5 KiB
C++
74 lines
2.5 KiB
C++
//===- MachineLoopInfo.cpp - Natural Loop Calculator ----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the MachineLoopInfo class that is used to identify natural
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// loops and determine the loop depth of various nodes of the CFG. Note that
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// the loops identified may actually be several natural loops that share the
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// same header node... not just a single natural loop.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/MachineLoopInfo.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/Passes.h"
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using namespace llvm;
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#define MLB class LoopBase<MachineBasicBlock, MachineLoop>
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TEMPLATE_INSTANTIATION(MLB);
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#undef MLB
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#define MLIB class LoopInfoBase<MachineBasicBlock, MachineLoop>
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TEMPLATE_INSTANTIATION(MLIB);
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#undef MLIB
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char MachineLoopInfo::ID = 0;
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static RegisterPass<MachineLoopInfo>
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X("machine-loops", "Machine Natural Loop Construction", true);
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const PassInfo *const llvm::MachineLoopInfoID = &X;
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bool MachineLoopInfo::runOnMachineFunction(MachineFunction &) {
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releaseMemory();
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LI.Calculate(getAnalysis<MachineDominatorTree>().getBase()); // Update
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return false;
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}
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void MachineLoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addRequired<MachineDominatorTree>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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MachineBasicBlock *MachineLoop::getTopBlock() {
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MachineBasicBlock *TopMBB = getHeader();
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MachineFunction::iterator Begin = TopMBB->getParent()->begin();
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if (TopMBB != Begin) {
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MachineBasicBlock *PriorMBB = prior(MachineFunction::iterator(TopMBB));
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while (contains(PriorMBB)) {
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TopMBB = PriorMBB;
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if (TopMBB == Begin) break;
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PriorMBB = prior(MachineFunction::iterator(TopMBB));
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}
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}
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return TopMBB;
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}
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MachineBasicBlock *MachineLoop::getBottomBlock() {
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MachineBasicBlock *BotMBB = getHeader();
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MachineFunction::iterator End = BotMBB->getParent()->end();
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if (BotMBB != prior(End)) {
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MachineBasicBlock *NextMBB = llvm::next(MachineFunction::iterator(BotMBB));
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while (contains(NextMBB)) {
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BotMBB = NextMBB;
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if (BotMBB == llvm::next(MachineFunction::iterator(BotMBB))) break;
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NextMBB = llvm::next(MachineFunction::iterator(BotMBB));
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}
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}
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return BotMBB;
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}
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