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#include "llvm/CodeGen/Passes.h" 18#include "llvm/CodeGen/MachineFunction.h" 19#include "llvm/CodeGen/MachineFunctionPass.h" 20#include "llvm/Support/Debug.h" 21#include "llvm/Target/TargetLowering.h" 22#include "llvm/Target/TargetMachine.h" 23using namespace llvm; 24 25#define DEBUG_TYPE "expand-isel-pseudos" 26 27namespace { 28 class ExpandISelPseudos : public MachineFunctionPass { 29 public: 30 static char ID; // Pass identification, replacement for typeid 31 ExpandISelPseudos() : MachineFunctionPass(ID) {} 32 33 private: 34 bool runOnMachineFunction(MachineFunction &MF) override; 35 36 void getAnalysisUsage(AnalysisUsage &AU) const override { 37 MachineFunctionPass::getAnalysisUsage(AU); 38 } 39 }; 40} // end anonymous namespace 41 42char ExpandISelPseudos::ID = 0; 43char &llvm::ExpandISelPseudosID = ExpandISelPseudos::ID; 44INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos", 45 "Expand ISel Pseudo-instructions", false, false) 46 47bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) { 48 bool Changed = false; 49 const TargetLowering *TLI = MF.getTarget().getTargetLowering(); 50 51 // Iterate through each instruction in the function, looking for pseudos. 52 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) { 53 MachineBasicBlock *MBB = I; 54 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end(); 55 MBBI != MBBE; ) { 56 MachineInstr *MI = MBBI++; 57 58 // If MI is a pseudo, expand it. 59 if (MI->usesCustomInsertionHook()) { 60 Changed = true; 61 MachineBasicBlock *NewMBB = 62 TLI->EmitInstrWithCustomInserter(MI, MBB); 63 // The expansion may involve new basic blocks. 64 if (NewMBB != MBB) { 65 MBB = NewMBB; 66 I = NewMBB; 67 MBBI = NewMBB->begin(); 68 MBBE = NewMBB->end(); 69 } 70 } 71 } 72 } 73 74 return Changed; 75} 76