MachineLoopInfo.cpp revision 9d59d9f8495b0361c9ffd1dc82888d8e7ba5070e 
1//===- MachineLoopInfo.cpp - Natural Loop Calculator ----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the MachineLoopInfo class that is used to identify natural
11// loops and determine the loop depth of various nodes of the CFG.  Note that
12// the loops identified may actually be several natural loops that share the
13// same header node... not just a single natural loop.
14//
15//===----------------------------------------------------------------------===//
16
17#include "llvm/CodeGen/MachineLoopInfo.h"
18#include "llvm/CodeGen/MachineDominators.h"
19#include "llvm/CodeGen/Passes.h"
20using namespace llvm;
21
22TEMPLATE_INSTANTIATION(class LoopBase<MachineBasicBlock>);
23TEMPLATE_INSTANTIATION(class LoopInfoBase<MachineBasicBlock>);
24
25char MachineLoopInfo::ID = 0;
26static RegisterPass<MachineLoopInfo>
27X("machine-loops", "Machine Natural Loop Construction", true);
28
29const PassInfo *const llvm::MachineLoopInfoID = &X;
30
31bool MachineLoopInfo::runOnMachineFunction(MachineFunction &) {
32  releaseMemory();
33  LI.Calculate(getAnalysis<MachineDominatorTree>().getBase());    // Update
34  return false;
35}
36
37void MachineLoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
38  AU.setPreservesAll();
39  AU.addRequired<MachineDominatorTree>();
40}
41