ExpandISelPseudos.cpp revision 5a96b3dad2f634c9081c8b2b6c2575441dc5a2bd
1//===-- llvm/CodeGen/ExpandISelPseudos.cpp ----------------------*- C++ -*-===// 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// Expand Pseudo-instructions produced by ISel. These are usually to allow 11// the expansion to contain control flow, such as a conditional move 12// implemented with a conditional branch and a phi, or an atomic operation 13// implemented with a loop. 14// 15//===----------------------------------------------------------------------===// 16 17#define DEBUG_TYPE "expand-isel-pseudos" 18#include "llvm/CodeGen/MachineFunction.h" 19#include "llvm/CodeGen/MachineFunctionPass.h" 20#include "llvm/CodeGen/Passes.h" 21#include "llvm/Target/TargetLowering.h" 22#include "llvm/Target/TargetMachine.h" 23#include "llvm/Support/Debug.h" 24using namespace llvm; 25 26namespace { 27 class ExpandISelPseudos : public MachineFunctionPass { 28 public: 29 static char ID; // Pass identification, replacement for typeid 30 ExpandISelPseudos() : MachineFunctionPass(ID) {} 31 32 private: 33 virtual bool runOnMachineFunction(MachineFunction &MF); 34 35 const char *getPassName() const { 36 return "Expand ISel Pseudo-instructions"; 37 } 38 39 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 40 MachineFunctionPass::getAnalysisUsage(AU); 41 } 42 }; 43} // end anonymous namespace 44 45char ExpandISelPseudos::ID = 0; 46INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos", 47 "Expand CodeGen Pseudo-instructions", false, false) 48 49FunctionPass *llvm::createExpandISelPseudosPass() { 50 return new ExpandISelPseudos(); 51} 52 53bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) { 54 bool Changed = false; 55 const TargetLowering *TLI = MF.getTarget().getTargetLowering(); 56 57 // Iterate through each instruction in the function, looking for pseudos. 58 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) { 59 MachineBasicBlock *MBB = I; 60 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end(); 61 MBBI != MBBE; ) { 62 MachineInstr *MI = MBBI++; 63 64 // If MI is a pseudo, expand it. 65 if (MI->usesCustomInsertionHook()) { 66 Changed = true; 67 MachineBasicBlock *NewMBB = 68 TLI->EmitInstrWithCustomInserter(MI, MBB); 69 // The expansion may involve new basic blocks. 70 if (NewMBB != MBB) { 71 MBB = NewMBB; 72 I = NewMBB; 73 MBBI = NewMBB->begin(); 74 MBBE = NewMBB->end(); 75 } 76 } 77 } 78 } 79 80 return Changed; 81} 82