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/TargetSubtargetInfo.h" 23 using namespace llvm; 24 25 #define DEBUG_TYPE "expand-isel-pseudos" 26 27 namespace { 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 42 char ExpandISelPseudos::ID = 0; 43 char &llvm::ExpandISelPseudosID = ExpandISelPseudos::ID; 44 INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos", 45 "Expand ISel Pseudo-instructions", false, false) 46 47 bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) { 48 bool Changed = false; 49 const TargetLowering *TLI = MF.getSubtarget().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 = TLI->EmitInstrWithCustomInserter(MI, MBB); 62 // The expansion may involve new basic blocks. 63 if (NewMBB != MBB) { 64 MBB = NewMBB; 65 I = NewMBB->getIterator(); 66 MBBI = NewMBB->begin(); 67 MBBE = NewMBB->end(); 68 } 69 } 70 } 71 } 72 73 return Changed; 74 } 75
