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 #define SYSTEMZ_COPYPHYSREGS_NAME "SystemZ Copy Physregs" 29 30 namespace llvm { 31 void initializeSystemZCopyPhysRegsPass(PassRegistry&); 32 } 33 34 namespace { 35 36 class SystemZCopyPhysRegs : public MachineFunctionPass { 37 public: 38 static char ID; 39 SystemZCopyPhysRegs() 40 : MachineFunctionPass(ID), TII(nullptr), MRI(nullptr) { 41 initializeSystemZCopyPhysRegsPass(*PassRegistry::getPassRegistry()); 42 } 43 44 StringRef getPassName() const override { return SYSTEMZ_COPYPHYSREGS_NAME; } 45 46 bool runOnMachineFunction(MachineFunction &MF) override; 47 void getAnalysisUsage(AnalysisUsage &AU) const override; 48 49 private: 50 51 bool visitMBB(MachineBasicBlock &MBB); 52 53 const SystemZInstrInfo *TII; 54 MachineRegisterInfo *MRI; 55 }; 56 57 char SystemZCopyPhysRegs::ID = 0; 58 59 } // end anonymous namespace 60 61 INITIALIZE_PASS(SystemZCopyPhysRegs, "systemz-copy-physregs", 62 SYSTEMZ_COPYPHYSREGS_NAME, false, false) 63 64 FunctionPass *llvm::createSystemZCopyPhysRegsPass(SystemZTargetMachine &TM) { 65 return new SystemZCopyPhysRegs(); 66 } 67 68 void SystemZCopyPhysRegs::getAnalysisUsage(AnalysisUsage &AU) const { 69 AU.setPreservesCFG(); 70 MachineFunctionPass::getAnalysisUsage(AU); 71 } 72 73 bool SystemZCopyPhysRegs::visitMBB(MachineBasicBlock &MBB) { 74 bool Modified = false; 75 76 // Certain special registers can only be copied from a subset of the 77 // default register class of the type. It is therefore necessary to create 78 // the target copy instructions before regalloc instead of in copyPhysReg(). 79 for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end(); 80 MBBI != E; ) { 81 MachineInstr *MI = &*MBBI++; 82 if (!MI->isCopy()) 83 continue; 84 85 DebugLoc DL = MI->getDebugLoc(); 86 Register SrcReg = MI->getOperand(1).getReg(); 87 Register DstReg = MI->getOperand(0).getReg(); 88 if (DstReg.isVirtual() && 89 (SrcReg == SystemZ::CC || SystemZ::AR32BitRegClass.contains(SrcReg))) { 90 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 91 if (SrcReg == SystemZ::CC) 92 BuildMI(MBB, MI, DL, TII->get(SystemZ::IPM), Tmp); 93 else 94 BuildMI(MBB, MI, DL, TII->get(SystemZ::EAR), Tmp).addReg(SrcReg); 95 MI->getOperand(1).setReg(Tmp); 96 Modified = true; 97 } 98 else if (SrcReg.isVirtual() && 99 SystemZ::AR32BitRegClass.contains(DstReg)) { 100 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass); 101 MI->getOperand(0).setReg(Tmp); 102 BuildMI(MBB, MBBI, DL, TII->get(SystemZ::SAR), DstReg).addReg(Tmp); 103 Modified = true; 104 } 105 } 106 107 return Modified; 108 } 109 110 bool SystemZCopyPhysRegs::runOnMachineFunction(MachineFunction &F) { 111 TII = static_cast<const SystemZInstrInfo *>(F.getSubtarget().getInstrInfo()); 112 MRI = &F.getRegInfo(); 113 114 bool Modified = false; 115 for (auto &MBB : F) 116 Modified |= visitMBB(MBB); 117 118 return Modified; 119 } 120 121