-//===- SparcInstrInfo.cpp - Sparc Instruction Information -------*- C++ -*-===//
+//===-- SparcInstrInfo.cpp - Sparc Instruction Information ----------------===//
//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "SparcInstrInfo.h"
#include "Sparc.h"
+#include "SparcMachineFunctionInfo.h"
+#include "SparcSubtarget.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "SparcGenInstrInfo.inc"
+#include "llvm/CodeGen/MachineMemOperand.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/TargetRegistry.h"
+
using namespace llvm;
-SparcInstrInfo::SparcInstrInfo(SparcSubtarget &ST)
- : TargetInstrInfo(SparcInsts, sizeof(SparcInsts)/sizeof(SparcInsts[0])),
- RI(ST) {
-}
+#define GET_INSTRINFO_CTOR_DTOR
+#include "SparcGenInstrInfo.inc"
-static bool isZeroImm(const MachineOperand &op) {
- return op.isImmediate() && op.getImmedValue() == 0;
-}
+// Pin the vtable to this file.
+void SparcInstrInfo::anchor() {}
-/// Return true if the instruction is a register to register move and
-/// leave the source and dest operands in the passed parameters.
-///
-bool SparcInstrInfo::isMoveInstr(const MachineInstr &MI,
- unsigned &SrcReg, unsigned &DstReg) const {
- // We look for 3 kinds of patterns here:
- // or with G0 or 0
- // add with G0 or 0
- // fmovs or FpMOVD (pseudo double move).
- if (MI.getOpcode() == SP::ORrr || MI.getOpcode() == SP::ADDrr) {
- if (MI.getOperand(1).getReg() == SP::G0) {
- DstReg = MI.getOperand(0).getReg();
- SrcReg = MI.getOperand(2).getReg();
- return true;
- } else if (MI.getOperand(2).getReg() == SP::G0) {
- DstReg = MI.getOperand(0).getReg();
- SrcReg = MI.getOperand(1).getReg();
- return true;
- }
- } else if ((MI.getOpcode() == SP::ORri || MI.getOpcode() == SP::ADDri) &&
- isZeroImm(MI.getOperand(2)) && MI.getOperand(1).isRegister()) {
- DstReg = MI.getOperand(0).getReg();
- SrcReg = MI.getOperand(1).getReg();
- return true;
- } else if (MI.getOpcode() == SP::FMOVS || MI.getOpcode() == SP::FpMOVD ||
- MI.getOpcode() == SP::FMOVD) {
- SrcReg = MI.getOperand(1).getReg();
- DstReg = MI.getOperand(0).getReg();
- return true;
- }
- return false;
-}
+SparcInstrInfo::SparcInstrInfo(SparcSubtarget &ST)
+ : SparcGenInstrInfo(SP::ADJCALLSTACKDOWN, SP::ADJCALLSTACKUP), RI(),
+ Subtarget(ST) {}
/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
-unsigned SparcInstrInfo::isLoadFromStackSlot(MachineInstr *MI,
+unsigned SparcInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
if (MI->getOpcode() == SP::LDri ||
+ MI->getOpcode() == SP::LDXri ||
MI->getOpcode() == SP::LDFri ||
- MI->getOpcode() == SP::LDDFri) {
- if (MI->getOperand(1).isFrameIndex() && MI->getOperand(2).isImmediate() &&
- MI->getOperand(2).getImmedValue() == 0) {
- FrameIndex = MI->getOperand(1).getFrameIndex();
+ MI->getOpcode() == SP::LDDFri ||
+ MI->getOpcode() == SP::LDQFri) {
+ if (MI->getOperand(1).isFI() && MI->getOperand(2).isImm() &&
+ MI->getOperand(2).getImm() == 0) {
+ FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
}
/// the source reg along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
-unsigned SparcInstrInfo::isStoreToStackSlot(MachineInstr *MI,
+unsigned SparcInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
if (MI->getOpcode() == SP::STri ||
+ MI->getOpcode() == SP::STXri ||
MI->getOpcode() == SP::STFri ||
- MI->getOpcode() == SP::STDFri) {
- if (MI->getOperand(0).isFrameIndex() && MI->getOperand(1).isImmediate() &&
- MI->getOperand(1).getImmedValue() == 0) {
- FrameIndex = MI->getOperand(0).getFrameIndex();
+ MI->getOpcode() == SP::STDFri ||
+ MI->getOpcode() == SP::STQFri) {
+ if (MI->getOperand(0).isFI() && MI->getOperand(1).isImm() &&
+ MI->getOperand(1).getImm() == 0) {
+ FrameIndex = MI->getOperand(0).getIndex();
return MI->getOperand(2).getReg();
}
}
return 0;
}
-void SparcInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
- MachineBasicBlock *FBB,
- const std::vector<MachineOperand> &Cond)const{
- // Can only insert uncond branches so far.
- assert(Cond.empty() && !FBB && TBB && "Can only handle uncond branches!");
- BuildMI(&MBB, SP::BA, 1).addMBB(TBB);
-}
\ No newline at end of file
+static bool IsIntegerCC(unsigned CC)
+{
+ return (CC <= SPCC::ICC_VC);
+}
+
+static SPCC::CondCodes GetOppositeBranchCondition(SPCC::CondCodes CC)
+{
+ switch(CC) {
+ case SPCC::ICC_A: return SPCC::ICC_N;
+ case SPCC::ICC_N: return SPCC::ICC_A;
+ case SPCC::ICC_NE: return SPCC::ICC_E;
+ case SPCC::ICC_E: return SPCC::ICC_NE;
+ case SPCC::ICC_G: return SPCC::ICC_LE;
+ case SPCC::ICC_LE: return SPCC::ICC_G;
+ case SPCC::ICC_GE: return SPCC::ICC_L;
+ case SPCC::ICC_L: return SPCC::ICC_GE;
+ case SPCC::ICC_GU: return SPCC::ICC_LEU;
+ case SPCC::ICC_LEU: return SPCC::ICC_GU;
+ case SPCC::ICC_CC: return SPCC::ICC_CS;
+ case SPCC::ICC_CS: return SPCC::ICC_CC;
+ case SPCC::ICC_POS: return SPCC::ICC_NEG;
+ case SPCC::ICC_NEG: return SPCC::ICC_POS;
+ case SPCC::ICC_VC: return SPCC::ICC_VS;
+ case SPCC::ICC_VS: return SPCC::ICC_VC;
+
+ case SPCC::FCC_A: return SPCC::FCC_N;
+ case SPCC::FCC_N: return SPCC::FCC_A;
+ case SPCC::FCC_U: return SPCC::FCC_O;
+ case SPCC::FCC_O: return SPCC::FCC_U;
+ case SPCC::FCC_G: return SPCC::FCC_ULE;
+ case SPCC::FCC_LE: return SPCC::FCC_UG;
+ case SPCC::FCC_UG: return SPCC::FCC_LE;
+ case SPCC::FCC_ULE: return SPCC::FCC_G;
+ case SPCC::FCC_L: return SPCC::FCC_UGE;
+ case SPCC::FCC_GE: return SPCC::FCC_UL;
+ case SPCC::FCC_UL: return SPCC::FCC_GE;
+ case SPCC::FCC_UGE: return SPCC::FCC_L;
+ case SPCC::FCC_LG: return SPCC::FCC_UE;
+ case SPCC::FCC_UE: return SPCC::FCC_LG;
+ case SPCC::FCC_NE: return SPCC::FCC_E;
+ case SPCC::FCC_E: return SPCC::FCC_NE;
+ }
+ llvm_unreachable("Invalid cond code");
+}
+
+static bool isUncondBranchOpcode(int Opc) { return Opc == SP::BA; }
+
+static bool isCondBranchOpcode(int Opc) {
+ return Opc == SP::FBCOND || Opc == SP::BCOND;
+}
+
+static bool isIndirectBranchOpcode(int Opc) {
+ return Opc == SP::BINDrr || Opc == SP::BINDri;
+}
+
+static void parseCondBranch(MachineInstr *LastInst, MachineBasicBlock *&Target,
+ SmallVectorImpl<MachineOperand> &Cond) {
+ Cond.push_back(MachineOperand::CreateImm(LastInst->getOperand(1).getImm()));
+ Target = LastInst->getOperand(0).getMBB();
+}
+
+bool SparcInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
+ MachineBasicBlock *&TBB,
+ MachineBasicBlock *&FBB,
+ SmallVectorImpl<MachineOperand> &Cond,
+ bool AllowModify) const {
+ MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr();
+ if (I == MBB.end())
+ return false;
+
+ if (!isUnpredicatedTerminator(I))
+ return false;
+
+ // Get the last instruction in the block.
+ MachineInstr *LastInst = I;
+ unsigned LastOpc = LastInst->getOpcode();
+
+ // If there is only one terminator instruction, process it.
+ if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
+ if (isUncondBranchOpcode(LastOpc)) {
+ TBB = LastInst->getOperand(0).getMBB();
+ return false;
+ }
+ if (isCondBranchOpcode(LastOpc)) {
+ // Block ends with fall-through condbranch.
+ parseCondBranch(LastInst, TBB, Cond);
+ return false;
+ }
+ return true; // Can't handle indirect branch.
+ }
+
+ // Get the instruction before it if it is a terminator.
+ MachineInstr *SecondLastInst = I;
+ unsigned SecondLastOpc = SecondLastInst->getOpcode();
+
+ // If AllowModify is true and the block ends with two or more unconditional
+ // branches, delete all but the first unconditional branch.
+ if (AllowModify && isUncondBranchOpcode(LastOpc)) {
+ while (isUncondBranchOpcode(SecondLastOpc)) {
+ LastInst->eraseFromParent();
+ LastInst = SecondLastInst;
+ LastOpc = LastInst->getOpcode();
+ if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
+ // Return now the only terminator is an unconditional branch.
+ TBB = LastInst->getOperand(0).getMBB();
+ return false;
+ } else {
+ SecondLastInst = I;
+ SecondLastOpc = SecondLastInst->getOpcode();
+ }
+ }
+ }
+
+ // If there are three terminators, we don't know what sort of block this is.
+ if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
+ return true;
+
+ // If the block ends with a B and a Bcc, handle it.
+ if (isCondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
+ parseCondBranch(SecondLastInst, TBB, Cond);
+ FBB = LastInst->getOperand(0).getMBB();
+ return false;
+ }
+
+ // If the block ends with two unconditional branches, handle it. The second
+ // one is not executed.
+ if (isUncondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
+ TBB = SecondLastInst->getOperand(0).getMBB();
+ return false;
+ }
+
+ // ...likewise if it ends with an indirect branch followed by an unconditional
+ // branch.
+ if (isIndirectBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
+ I = LastInst;
+ if (AllowModify)
+ I->eraseFromParent();
+ return true;
+ }
+
+ // Otherwise, can't handle this.
+ return true;
+}
+
+unsigned
+SparcInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
+ MachineBasicBlock *FBB,
+ ArrayRef<MachineOperand> Cond,
+ DebugLoc DL) const {
+ assert(TBB && "InsertBranch must not be told to insert a fallthrough");
+ assert((Cond.size() == 1 || Cond.size() == 0) &&
+ "Sparc branch conditions should have one component!");
+
+ if (Cond.empty()) {
+ assert(!FBB && "Unconditional branch with multiple successors!");
+ BuildMI(&MBB, DL, get(SP::BA)).addMBB(TBB);
+ return 1;
+ }
+
+ // Conditional branch
+ unsigned CC = Cond[0].getImm();
+
+ if (IsIntegerCC(CC))
+ BuildMI(&MBB, DL, get(SP::BCOND)).addMBB(TBB).addImm(CC);
+ else
+ BuildMI(&MBB, DL, get(SP::FBCOND)).addMBB(TBB).addImm(CC);
+ if (!FBB)
+ return 1;
+
+ BuildMI(&MBB, DL, get(SP::BA)).addMBB(FBB);
+ return 2;
+}
+
+unsigned SparcInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const
+{
+ MachineBasicBlock::iterator I = MBB.end();
+ unsigned Count = 0;
+ while (I != MBB.begin()) {
+ --I;
+
+ if (I->isDebugValue())
+ continue;
+
+ if (I->getOpcode() != SP::BA
+ && I->getOpcode() != SP::BCOND
+ && I->getOpcode() != SP::FBCOND)
+ break; // Not a branch
+
+ I->eraseFromParent();
+ I = MBB.end();
+ ++Count;
+ }
+ return Count;
+}
+
+bool SparcInstrInfo::ReverseBranchCondition(
+ SmallVectorImpl<MachineOperand> &Cond) const {
+ assert(Cond.size() == 1);
+ SPCC::CondCodes CC = static_cast<SPCC::CondCodes>(Cond[0].getImm());
+ Cond[0].setImm(GetOppositeBranchCondition(CC));
+ return false;
+}
+
+void SparcInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I, DebugLoc DL,
+ unsigned DestReg, unsigned SrcReg,
+ bool KillSrc) const {
+ unsigned numSubRegs = 0;
+ unsigned movOpc = 0;
+ const unsigned *subRegIdx = nullptr;
+ bool ExtraG0 = false;
+
+ const unsigned DW_SubRegsIdx[] = { SP::sub_even, SP::sub_odd };
+ const unsigned DFP_FP_SubRegsIdx[] = { SP::sub_even, SP::sub_odd };
+ const unsigned QFP_DFP_SubRegsIdx[] = { SP::sub_even64, SP::sub_odd64 };
+ const unsigned QFP_FP_SubRegsIdx[] = { SP::sub_even, SP::sub_odd,
+ SP::sub_odd64_then_sub_even,
+ SP::sub_odd64_then_sub_odd };
+
+ if (SP::IntRegsRegClass.contains(DestReg, SrcReg))
+ BuildMI(MBB, I, DL, get(SP::ORrr), DestReg).addReg(SP::G0)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ else if (SP::IntPairRegClass.contains(DestReg, SrcReg)) {
+ subRegIdx = DW_SubRegsIdx;
+ numSubRegs = 2;
+ movOpc = SP::ORrr;
+ ExtraG0 = true;
+ } else if (SP::FPRegsRegClass.contains(DestReg, SrcReg))
+ BuildMI(MBB, I, DL, get(SP::FMOVS), DestReg)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ else if (SP::DFPRegsRegClass.contains(DestReg, SrcReg)) {
+ if (Subtarget.isV9()) {
+ BuildMI(MBB, I, DL, get(SP::FMOVD), DestReg)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ } else {
+ // Use two FMOVS instructions.
+ subRegIdx = DFP_FP_SubRegsIdx;
+ numSubRegs = 2;
+ movOpc = SP::FMOVS;
+ }
+ } else if (SP::QFPRegsRegClass.contains(DestReg, SrcReg)) {
+ if (Subtarget.isV9()) {
+ if (Subtarget.hasHardQuad()) {
+ BuildMI(MBB, I, DL, get(SP::FMOVQ), DestReg)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ } else {
+ // Use two FMOVD instructions.
+ subRegIdx = QFP_DFP_SubRegsIdx;
+ numSubRegs = 2;
+ movOpc = SP::FMOVD;
+ }
+ } else {
+ // Use four FMOVS instructions.
+ subRegIdx = QFP_FP_SubRegsIdx;
+ numSubRegs = 4;
+ movOpc = SP::FMOVS;
+ }
+ } else if (SP::ASRRegsRegClass.contains(DestReg) &&
+ SP::IntRegsRegClass.contains(SrcReg)) {
+ BuildMI(MBB, I, DL, get(SP::WRASRrr), DestReg)
+ .addReg(SP::G0)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ } else if (SP::IntRegsRegClass.contains(DestReg) &&
+ SP::ASRRegsRegClass.contains(SrcReg)) {
+ BuildMI(MBB, I, DL, get(SP::RDASR), DestReg)
+ .addReg(SrcReg, getKillRegState(KillSrc));
+ } else
+ llvm_unreachable("Impossible reg-to-reg copy");
+
+ if (numSubRegs == 0 || subRegIdx == nullptr || movOpc == 0)
+ return;
+
+ const TargetRegisterInfo *TRI = &getRegisterInfo();
+ MachineInstr *MovMI = nullptr;
+
+ for (unsigned i = 0; i != numSubRegs; ++i) {
+ unsigned Dst = TRI->getSubReg(DestReg, subRegIdx[i]);
+ unsigned Src = TRI->getSubReg(SrcReg, subRegIdx[i]);
+ assert(Dst && Src && "Bad sub-register");
+
+ MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(movOpc), Dst);
+ if (ExtraG0)
+ MIB.addReg(SP::G0);
+ MIB.addReg(Src);
+ MovMI = MIB.getInstr();
+ }
+ // Add implicit super-register defs and kills to the last MovMI.
+ MovMI->addRegisterDefined(DestReg, TRI);
+ if (KillSrc)
+ MovMI->addRegisterKilled(SrcReg, TRI);
+}
+
+void SparcInstrInfo::
+storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
+ unsigned SrcReg, bool isKill, int FI,
+ const TargetRegisterClass *RC,
+ const TargetRegisterInfo *TRI) const {
+ DebugLoc DL;
+ if (I != MBB.end()) DL = I->getDebugLoc();
+
+ MachineFunction *MF = MBB.getParent();
+ const MachineFrameInfo &MFI = *MF->getFrameInfo();
+ MachineMemOperand *MMO = MF->getMachineMemOperand(
+ MachinePointerInfo::getFixedStack(*MF, FI), MachineMemOperand::MOStore,
+ MFI.getObjectSize(FI), MFI.getObjectAlignment(FI));
+
+ // On the order of operands here: think "[FrameIdx + 0] = SrcReg".
+ if (RC == &SP::I64RegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::STXri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else if (RC == &SP::IntRegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::STri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else if (RC == &SP::IntPairRegClass)
+ BuildMI(MBB, I, DL, get(SP::STDri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else if (RC == &SP::FPRegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::STFri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else if (SP::DFPRegsRegClass.hasSubClassEq(RC))
+ BuildMI(MBB, I, DL, get(SP::STDFri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else if (SP::QFPRegsRegClass.hasSubClassEq(RC))
+ // Use STQFri irrespective of its legality. If STQ is not legal, it will be
+ // lowered into two STDs in eliminateFrameIndex.
+ BuildMI(MBB, I, DL, get(SP::STQFri)).addFrameIndex(FI).addImm(0)
+ .addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
+ else
+ llvm_unreachable("Can't store this register to stack slot");
+}
+
+void SparcInstrInfo::
+loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
+ unsigned DestReg, int FI,
+ const TargetRegisterClass *RC,
+ const TargetRegisterInfo *TRI) const {
+ DebugLoc DL;
+ if (I != MBB.end()) DL = I->getDebugLoc();
+
+ MachineFunction *MF = MBB.getParent();
+ const MachineFrameInfo &MFI = *MF->getFrameInfo();
+ MachineMemOperand *MMO = MF->getMachineMemOperand(
+ MachinePointerInfo::getFixedStack(*MF, FI), MachineMemOperand::MOLoad,
+ MFI.getObjectSize(FI), MFI.getObjectAlignment(FI));
+
+ if (RC == &SP::I64RegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::LDXri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else if (RC == &SP::IntRegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::LDri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else if (RC == &SP::IntPairRegClass)
+ BuildMI(MBB, I, DL, get(SP::LDDri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else if (RC == &SP::FPRegsRegClass)
+ BuildMI(MBB, I, DL, get(SP::LDFri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else if (SP::DFPRegsRegClass.hasSubClassEq(RC))
+ BuildMI(MBB, I, DL, get(SP::LDDFri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else if (SP::QFPRegsRegClass.hasSubClassEq(RC))
+ // Use LDQFri irrespective of its legality. If LDQ is not legal, it will be
+ // lowered into two LDDs in eliminateFrameIndex.
+ BuildMI(MBB, I, DL, get(SP::LDQFri), DestReg).addFrameIndex(FI).addImm(0)
+ .addMemOperand(MMO);
+ else
+ llvm_unreachable("Can't load this register from stack slot");
+}
+
+unsigned SparcInstrInfo::getGlobalBaseReg(MachineFunction *MF) const
+{
+ SparcMachineFunctionInfo *SparcFI = MF->getInfo<SparcMachineFunctionInfo>();
+ unsigned GlobalBaseReg = SparcFI->getGlobalBaseReg();
+ if (GlobalBaseReg != 0)
+ return GlobalBaseReg;
+
+ // Insert the set of GlobalBaseReg into the first MBB of the function
+ MachineBasicBlock &FirstMBB = MF->front();
+ MachineBasicBlock::iterator MBBI = FirstMBB.begin();
+ MachineRegisterInfo &RegInfo = MF->getRegInfo();
+
+ const TargetRegisterClass *PtrRC =
+ Subtarget.is64Bit() ? &SP::I64RegsRegClass : &SP::IntRegsRegClass;
+ GlobalBaseReg = RegInfo.createVirtualRegister(PtrRC);
+
+ DebugLoc dl;
+
+ BuildMI(FirstMBB, MBBI, dl, get(SP::GETPCX), GlobalBaseReg);
+ SparcFI->setGlobalBaseReg(GlobalBaseReg);
+ return GlobalBaseReg;
+}