112 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// This pass makes sure that a COPY of a physical register will be10// implementable after register allocation in copyPhysReg() (this could be11// done in EmitInstrWithCustomInserter() instead if COPY instructions would12// 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 24using namespace llvm;25 26namespace {27 28class SystemZCopyPhysRegs : public MachineFunctionPass {29public:30 static char ID;31 SystemZCopyPhysRegs() : MachineFunctionPass(ID), TII(nullptr), MRI(nullptr) {}32 33 bool runOnMachineFunction(MachineFunction &MF) override;34 void getAnalysisUsage(AnalysisUsage &AU) const override;35 36private:37 38 bool visitMBB(MachineBasicBlock &MBB);39 40 const SystemZInstrInfo *TII;41 MachineRegisterInfo *MRI;42};43 44char SystemZCopyPhysRegs::ID = 0;45 46} // end anonymous namespace47 48INITIALIZE_PASS(SystemZCopyPhysRegs, "systemz-copy-physregs",49 "SystemZ Copy Physregs", false, false)50 51FunctionPass *llvm::createSystemZCopyPhysRegsPass(SystemZTargetMachine &TM) {52 return new SystemZCopyPhysRegs();53}54 55void SystemZCopyPhysRegs::getAnalysisUsage(AnalysisUsage &AU) const {56 AU.setPreservesCFG();57 MachineFunctionPass::getAnalysisUsage(AU);58}59 60bool SystemZCopyPhysRegs::visitMBB(MachineBasicBlock &MBB) {61 bool Modified = false;62 63 // Certain special registers can only be copied from a subset of the64 // default register class of the type. It is therefore necessary to create65 // the target copy instructions before regalloc instead of in copyPhysReg().66 for (MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();67 MBBI != E; ) {68 MachineInstr *MI = &*MBBI++;69 if (!MI->isCopy())70 continue;71 72 DebugLoc DL = MI->getDebugLoc();73 Register SrcReg = MI->getOperand(1).getReg();74 Register DstReg = MI->getOperand(0).getReg();75 76 if (DstReg.isVirtual() &&77 (SrcReg == SystemZ::CC || SystemZ::AR32BitRegClass.contains(SrcReg))) {78 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass);79 if (SrcReg == SystemZ::CC)80 BuildMI(MBB, MI, DL, TII->get(SystemZ::IPM), Tmp);81 else82 BuildMI(MBB, MI, DL, TII->get(SystemZ::EAR), Tmp).addReg(SrcReg);83 MI->getOperand(1).setReg(Tmp);84 Modified = true;85 }86 else if (SrcReg.isVirtual() &&87 SystemZ::AR32BitRegClass.contains(DstReg)) {88 Register Tmp = MRI->createVirtualRegister(&SystemZ::GR32BitRegClass);89 MI->getOperand(0).setReg(Tmp);90 MachineInstr *NMI =91 BuildMI(MBB, MBBI, DL, TII->get(SystemZ::SAR), DstReg).addReg(Tmp);92 // SAR now writes the final value to DstReg, so update debug values.93 MBB.getParent()->substituteDebugValuesForInst(*MI, *NMI);94 Modified = true;95 }96 }97 98 return Modified;99}100 101bool SystemZCopyPhysRegs::runOnMachineFunction(MachineFunction &F) {102 TII = F.getSubtarget<SystemZSubtarget>().getInstrInfo();103 MRI = &F.getRegInfo();104 105 bool Modified = false;106 for (auto &MBB : F)107 Modified |= visitMBB(MBB);108 109 return Modified;110}111 112