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/Passes.h" 19 #include "llvm/CodeGen/MachineFunction.h" 20 #include "llvm/CodeGen/MachineFunctionPass.h" 21 #include "llvm/Support/Debug.h" 22 #include "llvm/Target/TargetLowering.h" 23 #include "llvm/Target/TargetMachine.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 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 36 MachineFunctionPass::getAnalysisUsage(AU); 37 } 38 }; 39 } // end anonymous namespace 40 41 char ExpandISelPseudos::ID = 0; 42 char &llvm::ExpandISelPseudosID = ExpandISelPseudos::ID; 43 INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos", 44 "Expand ISel Pseudo-instructions", false, false) 45 46 bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) { 47 bool Changed = false; 48 const TargetLowering *TLI = MF.getTarget().getTargetLowering(); 49 50 // Iterate through each instruction in the function, looking for pseudos. 51 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) { 52 MachineBasicBlock *MBB = I; 53 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end(); 54 MBBI != MBBE; ) { 55 MachineInstr *MI = MBBI++; 56 57 // If MI is a pseudo, expand it. 58 if (MI->usesCustomInsertionHook()) { 59 Changed = true; 60 MachineBasicBlock *NewMBB = 61 TLI->EmitInstrWithCustomInserter(MI, MBB); 62 // The expansion may involve new basic blocks. 63 if (NewMBB != MBB) { 64 MBB = NewMBB; 65 I = NewMBB; 66 MBBI = NewMBB->begin(); 67 MBBE = NewMBB->end(); 68 } 69 } 70 } 71 } 72 73 return Changed; 74 } 75
