1 //===---------- SystemZPhysRegCopy.cpp - Handle phys reg copies -----------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This pass makes sure that a COPY of a physical register will be 10 // implementable after register allocation in copyPhysReg() (this could be 11 // done in EmitInstrWithCustomInserter() instead if COPY instructions would 12 // be passed to it). 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "SystemZTargetMachine.h" 17 #include "llvm/CodeGen/MachineDominators.h" 18 #include "llvm/CodeGen/MachineFunctionPass.h" 19 #include "llvm/CodeGen/MachineInstrBuilder.h" 20 #include "llvm/CodeGen/MachineRegisterInfo.h" 21 #include "llvm/CodeGen/TargetInstrInfo.h" 22 #include "llvm/CodeGen/TargetRegisterInfo.h" 23 24 using namespace llvm; 25 26 namespace { 27 28 class SystemZCopyPhysRegs : public MachineFunctionPass { 29 public: 30 static char ID; 31 SystemZCopyPhysRegs() 32 : MachineFunctionPass(ID), TII(nullptr), MRI(nullptr) { 33 initializeSystemZCopyPhysRegsPass(*PassRegistry::getPassRegistry()); 34 } 35 36 bool runOnMachineFunction(MachineFunction &MF) override; 37 void getAnalysisUsage(AnalysisUsage &AU) const override; 38 39 private: 40 41 bool visitMBB(MachineBasicBlock &MBB); 42 43 const SystemZInstrInfo *TII; 44 MachineRegisterInfo *MRI; 45 }; 46 47 char SystemZCopyPhysRegs::ID = 0; 48 49 } // end anonymous namespace 50 51 INITIALIZE_PASS(SystemZCopyPhysRegs, "systemz-copy-physregs", 52 "SystemZ Copy Physregs", false, false) 53 54 FunctionPass *llvm::createSystemZCopyPhysRegsPass(SystemZTargetMachine &TM) { 55 return new SystemZCopyPhysRegs(); 56 } 57 58 void SystemZCopyPhysRegs::getAnalysisUsage(AnalysisUsage &AU) const { 59 AU.setPreservesCFG(); 60 MachineFunctionPass::getAnalysisUsage(AU); 61 } 62 63 bool SystemZCopyPhysRegs::visitMBB(MachineBasicBlock &MBB) { 64 bool Modified = false; 65 66 // Certain special registers can only be copied from a subset of the 67 // default register class of the type. It is therefore necessary to create 68 // the target copy instructions before regalloc instead of in copyPhysReg(). 69 for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end(); 70 MBBI != E; ) { 71 MachineInstr *MI = &*MBBI++; 72 if (!MI->isCopy()) 73 continue; 74 75 DebugLoc DL = MI->getDebugLoc(); 76 Register SrcReg = MI->getOperand(1).getReg(); 77 Register DstReg = MI->getOperand(0).getReg(); 78 if (DstReg.isVirtual() && 79 (SrcReg == SystemZ::CC || SystemZ::AR32BitRegClass.contains(SrcReg))) { 80 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 81 if (SrcReg == SystemZ::CC) 82 BuildMI(MBB, MI, DL, TII->get(SystemZ::IPM), Tmp); 83 else 84 BuildMI(MBB, MI, DL, TII->get(SystemZ::EAR), Tmp).addReg(SrcReg); 85 MI->getOperand(1).setReg(Tmp); 86 Modified = true; 87 } 88 else if (SrcReg.isVirtual() && 89 SystemZ::AR32BitRegClass.contains(DstReg)) { 90 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 91 MI->getOperand(0).setReg(Tmp); 92 BuildMI(MBB, MBBI, DL, TII->get(SystemZ::SAR), DstReg).addReg(Tmp); 93 Modified = true; 94 } 95 } 96 97 return Modified; 98 } 99 100 bool SystemZCopyPhysRegs::runOnMachineFunction(MachineFunction &F) { 101 TII = F.getSubtarget<SystemZSubtarget>().getInstrInfo(); 102 MRI = &F.getRegInfo(); 103 104 bool Modified = false; 105 for (auto &MBB : F) 106 Modified |= visitMBB(MBB); 107 108 return Modified; 109 } 110 111