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" 20 using namespace llvm; 21 22 #define MLB class LoopBase<MachineBasicBlock, MachineLoop> 23 TEMPLATE_INSTANTIATION(MLB); 24 #undef MLB 25 #define MLIB class LoopInfoBase<MachineBasicBlock, MachineLoop> 26 TEMPLATE_INSTANTIATION(MLIB); 27 #undef MLIB 28 29 char MachineLoopInfo::ID = 0; 30 static RegisterPass<MachineLoopInfo> 31 X("machine-loops", "Machine Natural Loop Construction", true); 32 33 const PassInfo *const llvm::MachineLoopInfoID = &X; 34 35 bool MachineLoopInfo::runOnMachineFunction(MachineFunction &) { 36 releaseMemory(); 37 LI.Calculate(getAnalysis<MachineDominatorTree>().getBase()); // Update 38 return false; 39 } 40 41 void MachineLoopInfo::getAnalysisUsage(AnalysisUsage &AU) const { 42 AU.setPreservesAll(); 43 AU.addRequired<MachineDominatorTree>(); 44 } 45