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 "SystemZMachineFunctionInfo.h" 17 #include "SystemZTargetMachine.h" 18 #include "llvm/CodeGen/MachineDominators.h" 19 #include "llvm/CodeGen/MachineFunctionPass.h" 20 #include "llvm/CodeGen/MachineInstrBuilder.h" 21 #include "llvm/CodeGen/MachineRegisterInfo.h" 22 #include "llvm/CodeGen/TargetInstrInfo.h" 23 #include "llvm/CodeGen/TargetRegisterInfo.h" 24 #include "llvm/Target/TargetMachine.h" 25 26 using namespace llvm; 27 28 namespace { 29 30 class SystemZCopyPhysRegs : public MachineFunctionPass { 31 public: 32 static char ID; 33 SystemZCopyPhysRegs() 34 : MachineFunctionPass(ID), TII(nullptr), MRI(nullptr) { 35 initializeSystemZCopyPhysRegsPass(*PassRegistry::getPassRegistry()); 36 } 37 38 bool runOnMachineFunction(MachineFunction &MF) override; 39 void getAnalysisUsage(AnalysisUsage &AU) const override; 40 41 private: 42 43 bool visitMBB(MachineBasicBlock &MBB); 44 45 const SystemZInstrInfo *TII; 46 MachineRegisterInfo *MRI; 47 }; 48 49 char SystemZCopyPhysRegs::ID = 0; 50 51 } // end anonymous namespace 52 53 INITIALIZE_PASS(SystemZCopyPhysRegs, "systemz-copy-physregs", 54 "SystemZ Copy Physregs", false, false) 55 56 FunctionPass *llvm::createSystemZCopyPhysRegsPass(SystemZTargetMachine &TM) { 57 return new SystemZCopyPhysRegs(); 58 } 59 60 void SystemZCopyPhysRegs::getAnalysisUsage(AnalysisUsage &AU) const { 61 AU.setPreservesCFG(); 62 MachineFunctionPass::getAnalysisUsage(AU); 63 } 64 65 bool SystemZCopyPhysRegs::visitMBB(MachineBasicBlock &MBB) { 66 bool Modified = false; 67 68 // Certain special registers can only be copied from a subset of the 69 // default register class of the type. It is therefore necessary to create 70 // the target copy instructions before regalloc instead of in copyPhysReg(). 71 for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end(); 72 MBBI != E; ) { 73 MachineInstr *MI = &*MBBI++; 74 if (!MI->isCopy()) 75 continue; 76 77 DebugLoc DL = MI->getDebugLoc(); 78 Register SrcReg = MI->getOperand(1).getReg(); 79 Register DstReg = MI->getOperand(0).getReg(); 80 if (DstReg.isVirtual() && 81 (SrcReg == SystemZ::CC || SystemZ::AR32BitRegClass.contains(SrcReg))) { 82 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 83 if (SrcReg == SystemZ::CC) 84 BuildMI(MBB, MI, DL, TII->get(SystemZ::IPM), Tmp); 85 else 86 BuildMI(MBB, MI, DL, TII->get(SystemZ::EAR), Tmp).addReg(SrcReg); 87 MI->getOperand(1).setReg(Tmp); 88 Modified = true; 89 } 90 else if (SrcReg.isVirtual() && 91 SystemZ::AR32BitRegClass.contains(DstReg)) { 92 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 93 MI->getOperand(0).setReg(Tmp); 94 BuildMI(MBB, MBBI, DL, TII->get(SystemZ::SAR), DstReg).addReg(Tmp); 95 Modified = true; 96 } 97 } 98 99 return Modified; 100 } 101 102 bool SystemZCopyPhysRegs::runOnMachineFunction(MachineFunction &F) { 103 TII = static_cast<const SystemZInstrInfo *>(F.getSubtarget().getInstrInfo()); 104 MRI = &F.getRegInfo(); 105 106 bool Modified = false; 107 for (auto &MBB : F) 108 Modified |= visitMBB(MBB); 109 110 return Modified; 111 } 112 113