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" 24 using namespace llvm; 25 26 namespace { 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 45 char ExpandISelPseudos::ID = 0; 46 INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos", 47 "Expand CodeGen Pseudo-instructions", false, false) 48 49 FunctionPass *llvm::createExpandISelPseudosPass() { 50 return new ExpandISelPseudos(); 51 } 52 53 bool 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 const MCInstrDesc &MCID = MI->getDesc(); 66 if (MCID.usesCustomInsertionHook()) { 67 Changed = true; 68 MachineBasicBlock *NewMBB = 69 TLI->EmitInstrWithCustomInserter(MI, MBB); 70 // The expansion may involve new basic blocks. 71 if (NewMBB != MBB) { 72 MBB = NewMBB; 73 I = NewMBB; 74 MBBI = NewMBB->begin(); 75 MBBE = NewMBB->end(); 76 } 77 } 78 } 79 } 80 81 return Changed; 82 } 83
