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llvm-mirror/lib/Target/ARM/ThumbRegisterInfo.cpp
Diana Picus c94e029b4a [ARM] Use helpers for adding pred / CC operands. NFC 
Hunt down some of the places where we use bare addReg(0) or addImm(AL).addReg(0)
and replace with add(condCodeOp()) and add(predOps()). This should make it
easier to understand what those operands represent (without having to look at
the definition of the instruction that we're adding to).

Differential Revision: https://reviews.llvm.org/D27984

llvm-svn: 292587
2017-01-20 08:15:24 +00:00

634 lines
24 KiB
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//===-- ThumbRegisterInfo.cpp - Thumb-1 Register Information -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Thumb-1 implementation of the TargetRegisterInfo
// class.
//
//===----------------------------------------------------------------------===//
#include "ThumbRegisterInfo.h"
#include "ARMBaseInstrInfo.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
#include "MCTargetDesc/ARMAddressingModes.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetMachine.h"
namespace llvm {
extern cl::opt<bool> ReuseFrameIndexVals;
}
using namespace llvm;
ThumbRegisterInfo::ThumbRegisterInfo() : ARMBaseRegisterInfo() {}
const TargetRegisterClass *
ThumbRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC,
const MachineFunction &MF) const {
if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only())
return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF);
if (ARM::tGPRRegClass.hasSubClassEq(RC))
return &ARM::tGPRRegClass;
return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF);
}
const TargetRegisterClass *
ThumbRegisterInfo::getPointerRegClass(const MachineFunction &MF,
unsigned Kind) const {
if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only())
return ARMBaseRegisterInfo::getPointerRegClass(MF, Kind);
return &ARM::tGPRRegClass;
}
static void emitThumb1LoadConstPool(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
const DebugLoc &dl, unsigned DestReg,
unsigned SubIdx, int Val,
ARMCC::CondCodes Pred, unsigned PredReg,
unsigned MIFlags) {
MachineFunction &MF = *MBB.getParent();
const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
const TargetInstrInfo &TII = *STI.getInstrInfo();
MachineConstantPool *ConstantPool = MF.getConstantPool();
const Constant *C = ConstantInt::get(
Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRpci))
.addReg(DestReg, getDefRegState(true), SubIdx)
.addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg)
.setMIFlags(MIFlags);
}
static void emitThumb2LoadConstPool(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
const DebugLoc &dl, unsigned DestReg,
unsigned SubIdx, int Val,
ARMCC::CondCodes Pred, unsigned PredReg,
unsigned MIFlags) {
MachineFunction &MF = *MBB.getParent();
const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
MachineConstantPool *ConstantPool = MF.getConstantPool();
const Constant *C = ConstantInt::get(
Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci))
.addReg(DestReg, getDefRegState(true), SubIdx)
.addConstantPoolIndex(Idx)
.add(predOps(ARMCC::AL))
.setMIFlags(MIFlags);
}
/// emitLoadConstPool - Emits a load from constpool to materialize the
/// specified immediate.
void ThumbRegisterInfo::emitLoadConstPool(
MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
const DebugLoc &dl, unsigned DestReg, unsigned SubIdx, int Val,
ARMCC::CondCodes Pred, unsigned PredReg, unsigned MIFlags) const {
MachineFunction &MF = *MBB.getParent();
const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
if (STI.isThumb1Only()) {
assert((isARMLowRegister(DestReg) || isVirtualRegister(DestReg)) &&
"Thumb1 does not have ldr to high register");
return emitThumb1LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred,
PredReg, MIFlags);
}
return emitThumb2LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred,
PredReg, MIFlags);
}
/// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
/// a destreg = basereg + immediate in Thumb code. Materialize the immediate
/// in a register using mov / mvn sequences or load the immediate from a
/// constpool entry.
static void emitThumbRegPlusImmInReg(
MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
const DebugLoc &dl, unsigned DestReg, unsigned BaseReg, int NumBytes,
bool CanChangeCC, const TargetInstrInfo &TII,
const ARMBaseRegisterInfo &MRI, unsigned MIFlags = MachineInstr::NoFlags) {
MachineFunction &MF = *MBB.getParent();
const ARMSubtarget &ST = MF.getSubtarget<ARMSubtarget>();
bool isHigh = !isARMLowRegister(DestReg) ||
(BaseReg != 0 && !isARMLowRegister(BaseReg));
bool isSub = false;
// Subtract doesn't have high register version. Load the negative value
// if either base or dest register is a high register. Also, if do not
// issue sub as part of the sequence if condition register is to be
// preserved.
if (NumBytes < 0 && !isHigh && CanChangeCC) {
isSub = true;
NumBytes = -NumBytes;
}
unsigned LdReg = DestReg;
if (DestReg == ARM::SP)
assert(BaseReg == ARM::SP && "Unexpected!");
if (!isARMLowRegister(DestReg) && !MRI.isVirtualRegister(DestReg))
LdReg = MF.getRegInfo().createVirtualRegister(&ARM::tGPRRegClass);
if (NumBytes <= 255 && NumBytes >= 0 && CanChangeCC) {
BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg)
.add(t1CondCodeOp())
.addImm(NumBytes)
.setMIFlags(MIFlags);
} else if (NumBytes < 0 && NumBytes >= -255 && CanChangeCC) {
BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg)
.add(t1CondCodeOp())
.addImm(NumBytes)
.setMIFlags(MIFlags);
BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg)
.add(t1CondCodeOp())
.addReg(LdReg, RegState::Kill)
.setMIFlags(MIFlags);
} else if (ST.genExecuteOnly()) {
BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), LdReg)
.addImm(NumBytes).setMIFlags(MIFlags);
} else
MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes, ARMCC::AL, 0,
MIFlags);
// Emit add / sub.
int Opc = (isSub) ? ARM::tSUBrr
: ((isHigh || !CanChangeCC) ? ARM::tADDhirr : ARM::tADDrr);
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
if (Opc != ARM::tADDhirr)
MIB = MIB.add(t1CondCodeOp());
if (DestReg == ARM::SP || isSub)
MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
else
MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
MIB.add(predOps(ARMCC::AL));
}
/// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
/// a destreg = basereg + immediate in Thumb code. Tries a series of ADDs or
/// SUBs first, and uses a constant pool value if the instruction sequence would
/// be too long. This is allowed to modify the condition flags.
void llvm::emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
const DebugLoc &dl, unsigned DestReg,
unsigned BaseReg, int NumBytes,
const TargetInstrInfo &TII,
const ARMBaseRegisterInfo &MRI,
unsigned MIFlags) {
bool isSub = NumBytes < 0;
unsigned Bytes = (unsigned)NumBytes;
if (isSub) Bytes = -NumBytes;
int CopyOpc = 0;
unsigned CopyBits = 0;
unsigned CopyScale = 1;
bool CopyNeedsCC = false;
int ExtraOpc = 0;
unsigned ExtraBits = 0;
unsigned ExtraScale = 1;
bool ExtraNeedsCC = false;
// Strategy:
// We need to select two types of instruction, maximizing the available
// immediate range of each. The instructions we use will depend on whether
// DestReg and BaseReg are low, high or the stack pointer.
// * CopyOpc - DestReg = BaseReg + imm
// This will be emitted once if DestReg != BaseReg, and never if
// DestReg == BaseReg.
// * ExtraOpc - DestReg = DestReg + imm
// This will be emitted as many times as necessary to add the
// full immediate.
// If the immediate ranges of these instructions are not large enough to cover
// NumBytes with a reasonable number of instructions, we fall back to using a
// value loaded from a constant pool.
if (DestReg == ARM::SP) {
if (BaseReg == ARM::SP) {
// sp -> sp
// Already in right reg, no copy needed
} else {
// low -> sp or high -> sp
CopyOpc = ARM::tMOVr;
CopyBits = 0;
}
ExtraOpc = isSub ? ARM::tSUBspi : ARM::tADDspi;
ExtraBits = 7;
ExtraScale = 4;
} else if (isARMLowRegister(DestReg)) {
if (BaseReg == ARM::SP) {
// sp -> low
assert(!isSub && "Thumb1 does not have tSUBrSPi");
CopyOpc = ARM::tADDrSPi;
CopyBits = 8;
CopyScale = 4;
} else if (DestReg == BaseReg) {
// low -> same low
// Already in right reg, no copy needed
} else if (isARMLowRegister(BaseReg)) {
// low -> different low
CopyOpc = isSub ? ARM::tSUBi3 : ARM::tADDi3;
CopyBits = 3;
CopyNeedsCC = true;
} else {
// high -> low
CopyOpc = ARM::tMOVr;
CopyBits = 0;
}
ExtraOpc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
ExtraBits = 8;
ExtraNeedsCC = true;
} else /* DestReg is high */ {
if (DestReg == BaseReg) {
// high -> same high
// Already in right reg, no copy needed
} else {
// {low,high,sp} -> high
CopyOpc = ARM::tMOVr;
CopyBits = 0;
}
ExtraOpc = 0;
}
// We could handle an unaligned immediate with an unaligned copy instruction
// and an aligned extra instruction, but this case is not currently needed.
assert(((Bytes & 3) == 0 || ExtraScale == 1) &&
"Unaligned offset, but all instructions require alignment");
unsigned CopyRange = ((1 << CopyBits) - 1) * CopyScale;
// If we would emit the copy with an immediate of 0, just use tMOVr.
if (CopyOpc && Bytes < CopyScale) {
CopyOpc = ARM::tMOVr;
CopyScale = 1;
CopyNeedsCC = false;
CopyRange = 0;
}
unsigned ExtraRange = ((1 << ExtraBits) - 1) * ExtraScale; // per instruction
unsigned RequiredCopyInstrs = CopyOpc ? 1 : 0;
unsigned RangeAfterCopy = (CopyRange > Bytes) ? 0 : (Bytes - CopyRange);
// We could handle this case when the copy instruction does not require an
// aligned immediate, but we do not currently do this.
assert(RangeAfterCopy % ExtraScale == 0 &&
"Extra instruction requires immediate to be aligned");
unsigned RequiredExtraInstrs;
if (ExtraRange)
RequiredExtraInstrs = alignTo(RangeAfterCopy, ExtraRange) / ExtraRange;
else if (RangeAfterCopy > 0)
// We need an extra instruction but none is available
RequiredExtraInstrs = 1000000;
else
RequiredExtraInstrs = 0;
unsigned RequiredInstrs = RequiredCopyInstrs + RequiredExtraInstrs;
unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
// Use a constant pool, if the sequence of ADDs/SUBs is too expensive.
if (RequiredInstrs > Threshold) {
emitThumbRegPlusImmInReg(MBB, MBBI, dl,
DestReg, BaseReg, NumBytes, true,
TII, MRI, MIFlags);
return;
}
// Emit zero or one copy instructions
if (CopyOpc) {
unsigned CopyImm = std::min(Bytes, CopyRange) / CopyScale;
Bytes -= CopyImm * CopyScale;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(CopyOpc), DestReg);
if (CopyNeedsCC)
MIB = MIB.add(t1CondCodeOp());
MIB.addReg(BaseReg, RegState::Kill);
if (CopyOpc != ARM::tMOVr) {
MIB.addImm(CopyImm);
}
MIB.setMIFlags(MIFlags).add(predOps(ARMCC::AL));
BaseReg = DestReg;
}
// Emit zero or more in-place add/sub instructions
while (Bytes) {
unsigned ExtraImm = std::min(Bytes, ExtraRange) / ExtraScale;
Bytes -= ExtraImm * ExtraScale;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ExtraOpc), DestReg);
if (ExtraNeedsCC)
MIB = MIB.add(t1CondCodeOp());
MIB.addReg(BaseReg)
.addImm(ExtraImm)
.add(predOps(ARMCC::AL))
.setMIFlags(MIFlags);
}
}
static void removeOperands(MachineInstr &MI, unsigned i) {
unsigned Op = i;
for (unsigned e = MI.getNumOperands(); i != e; ++i)
MI.RemoveOperand(Op);
}
/// convertToNonSPOpcode - Change the opcode to the non-SP version, because
/// we're replacing the frame index with a non-SP register.
static unsigned convertToNonSPOpcode(unsigned Opcode) {
switch (Opcode) {
case ARM::tLDRspi:
return ARM::tLDRi;
case ARM::tSTRspi:
return ARM::tSTRi;
}
return Opcode;
}
bool ThumbRegisterInfo::rewriteFrameIndex(MachineBasicBlock::iterator II,
unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII) const {
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
assert(MBB.getParent()->getSubtarget<ARMSubtarget>().isThumb1Only() &&
"This isn't needed for thumb2!");
DebugLoc dl = MI.getDebugLoc();
MachineInstrBuilder MIB(*MBB.getParent(), &MI);
unsigned Opcode = MI.getOpcode();
const MCInstrDesc &Desc = MI.getDesc();
unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
if (Opcode == ARM::tADDframe) {
Offset += MI.getOperand(FrameRegIdx+1).getImm();
unsigned DestReg = MI.getOperand(0).getReg();
emitThumbRegPlusImmediate(MBB, II, dl, DestReg, FrameReg, Offset, TII,
*this);
MBB.erase(II);
return true;
} else {
if (AddrMode != ARMII::AddrModeT1_s)
llvm_unreachable("Unsupported addressing mode!");
unsigned ImmIdx = FrameRegIdx + 1;
int InstrOffs = MI.getOperand(ImmIdx).getImm();
unsigned NumBits = (FrameReg == ARM::SP) ? 8 : 5;
unsigned Scale = 4;
Offset += InstrOffs * Scale;
assert((Offset & (Scale - 1)) == 0 && "Can't encode this offset!");
// Common case: small offset, fits into instruction.
MachineOperand &ImmOp = MI.getOperand(ImmIdx);
int ImmedOffset = Offset / Scale;
unsigned Mask = (1 << NumBits) - 1;
if ((unsigned)Offset <= Mask * Scale) {
// Replace the FrameIndex with the frame register (e.g., sp).
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
ImmOp.ChangeToImmediate(ImmedOffset);
// If we're using a register where sp was stored, convert the instruction
// to the non-SP version.
unsigned NewOpc = convertToNonSPOpcode(Opcode);
if (NewOpc != Opcode && FrameReg != ARM::SP)
MI.setDesc(TII.get(NewOpc));
return true;
}
NumBits = 5;
Mask = (1 << NumBits) - 1;
// If this is a thumb spill / restore, we will be using a constpool load to
// materialize the offset.
if (Opcode == ARM::tLDRspi || Opcode == ARM::tSTRspi) {
ImmOp.ChangeToImmediate(0);
} else {
// Otherwise, it didn't fit. Pull in what we can to simplify the immed.
ImmedOffset = ImmedOffset & Mask;
ImmOp.ChangeToImmediate(ImmedOffset);
Offset &= ~(Mask * Scale);
}
}
return Offset == 0;
}
void ThumbRegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
int64_t Offset) const {
const MachineFunction &MF = *MI.getParent()->getParent();
const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
if (!STI.isThumb1Only())
return ARMBaseRegisterInfo::resolveFrameIndex(MI, BaseReg, Offset);
const ARMBaseInstrInfo &TII = *STI.getInstrInfo();
int Off = Offset; // ARM doesn't need the general 64-bit offsets
unsigned i = 0;
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
bool Done = rewriteFrameIndex(MI, i, BaseReg, Off, TII);
assert (Done && "Unable to resolve frame index!");
(void)Done;
}
/// saveScavengerRegister - Spill the register so it can be used by the
/// register scavenger. Return true.
bool ThumbRegisterInfo::saveScavengerRegister(
MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
MachineBasicBlock::iterator &UseMI, const TargetRegisterClass *RC,
unsigned Reg) const {
const ARMSubtarget &STI = MBB.getParent()->getSubtarget<ARMSubtarget>();
if (!STI.isThumb1Only())
return ARMBaseRegisterInfo::saveScavengerRegister(MBB, I, UseMI, RC, Reg);
// Thumb1 can't use the emergency spill slot on the stack because
// ldr/str immediate offsets must be positive, and if we're referencing
// off the frame pointer (if, for example, there are alloca() calls in
// the function, the offset will be negative. Use R12 instead since that's
// a call clobbered register that we know won't be used in Thumb1 mode.
const TargetInstrInfo &TII = *STI.getInstrInfo();
DebugLoc DL;
BuildMI(MBB, I, DL, TII.get(ARM::tMOVr))
.addReg(ARM::R12, RegState::Define)
.addReg(Reg, RegState::Kill)
.add(predOps(ARMCC::AL));
// The UseMI is where we would like to restore the register. If there's
// interference with R12 before then, however, we'll need to restore it
// before that instead and adjust the UseMI.
bool done = false;
for (MachineBasicBlock::iterator II = I; !done && II != UseMI ; ++II) {
if (II->isDebugValue())
continue;
// If this instruction affects R12, adjust our restore point.
for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = II->getOperand(i);
if (MO.isRegMask() && MO.clobbersPhysReg(ARM::R12)) {
UseMI = II;
done = true;
break;
}
if (!MO.isReg() || MO.isUndef() || !MO.getReg() ||
TargetRegisterInfo::isVirtualRegister(MO.getReg()))
continue;
if (MO.getReg() == ARM::R12) {
UseMI = II;
done = true;
break;
}
}
}
// Restore the register from R12
BuildMI(MBB, UseMI, DL, TII.get(ARM::tMOVr))
.addReg(Reg, RegState::Define)
.addReg(ARM::R12, RegState::Kill)
.add(predOps(ARMCC::AL));
return true;
}
void ThumbRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
if (!STI.isThumb1Only())
return ARMBaseRegisterInfo::eliminateFrameIndex(II, SPAdj, FIOperandNum,
RS);
unsigned VReg = 0;
const ARMBaseInstrInfo &TII = *STI.getInstrInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
DebugLoc dl = MI.getDebugLoc();
MachineInstrBuilder MIB(*MBB.getParent(), &MI);
unsigned FrameReg = ARM::SP;
int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
int Offset = MF.getFrameInfo().getObjectOffset(FrameIndex) +
MF.getFrameInfo().getStackSize() + SPAdj;
if (MF.getFrameInfo().hasVarSizedObjects()) {
assert(SPAdj == 0 && STI.getFrameLowering()->hasFP(MF) && "Unexpected");
// There are alloca()'s in this function, must reference off the frame
// pointer or base pointer instead.
if (!hasBasePointer(MF)) {
FrameReg = getFrameRegister(MF);
Offset -= AFI->getFramePtrSpillOffset();
} else
FrameReg = BasePtr;
}
// PEI::scavengeFrameVirtualRegs() cannot accurately track SPAdj because the
// call frame setup/destroy instructions have already been eliminated. That
// means the stack pointer cannot be used to access the emergency spill slot
// when !hasReservedCallFrame().
#ifndef NDEBUG
if (RS && FrameReg == ARM::SP && RS->isScavengingFrameIndex(FrameIndex)){
assert(STI.getFrameLowering()->hasReservedCallFrame(MF) &&
"Cannot use SP to access the emergency spill slot in "
"functions without a reserved call frame");
assert(!MF.getFrameInfo().hasVarSizedObjects() &&
"Cannot use SP to access the emergency spill slot in "
"functions with variable sized frame objects");
}
#endif // NDEBUG
// Special handling of dbg_value instructions.
if (MI.isDebugValue()) {
MI.getOperand(FIOperandNum). ChangeToRegister(FrameReg, false /*isDef*/);
MI.getOperand(FIOperandNum+1).ChangeToImmediate(Offset);
return;
}
// Modify MI as necessary to handle as much of 'Offset' as possible
assert(AFI->isThumbFunction() &&
"This eliminateFrameIndex only supports Thumb1!");
if (rewriteFrameIndex(MI, FIOperandNum, FrameReg, Offset, TII))
return;
// If we get here, the immediate doesn't fit into the instruction. We folded
// as much as possible above, handle the rest, providing a register that is
// SP+LargeImm.
assert(Offset && "This code isn't needed if offset already handled!");
unsigned Opcode = MI.getOpcode();
// Remove predicate first.
int PIdx = MI.findFirstPredOperandIdx();
if (PIdx != -1)
removeOperands(MI, PIdx);
if (MI.mayLoad()) {
// Use the destination register to materialize sp + offset.
unsigned TmpReg = MI.getOperand(0).getReg();
bool UseRR = false;
if (Opcode == ARM::tLDRspi) {
if (FrameReg == ARM::SP || STI.genExecuteOnly())
emitThumbRegPlusImmInReg(MBB, II, dl, TmpReg, FrameReg,
Offset, false, TII, *this);
else {
emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
UseRR = true;
}
} else {
emitThumbRegPlusImmediate(MBB, II, dl, TmpReg, FrameReg, Offset, TII,
*this);
}
MI.setDesc(TII.get(UseRR ? ARM::tLDRr : ARM::tLDRi));
MI.getOperand(FIOperandNum).ChangeToRegister(TmpReg, false, false, true);
if (UseRR)
// Use [reg, reg] addrmode. Replace the immediate operand w/ the frame
// register. The offset is already handled in the vreg value.
MI.getOperand(FIOperandNum+1).ChangeToRegister(FrameReg, false, false,
false);
} else if (MI.mayStore()) {
VReg = MF.getRegInfo().createVirtualRegister(&ARM::tGPRRegClass);
bool UseRR = false;
if (Opcode == ARM::tSTRspi) {
if (FrameReg == ARM::SP || STI.genExecuteOnly())
emitThumbRegPlusImmInReg(MBB, II, dl, VReg, FrameReg,
Offset, false, TII, *this);
else {
emitLoadConstPool(MBB, II, dl, VReg, 0, Offset);
UseRR = true;
}
} else
emitThumbRegPlusImmediate(MBB, II, dl, VReg, FrameReg, Offset, TII,
*this);
MI.setDesc(TII.get(UseRR ? ARM::tSTRr : ARM::tSTRi));
MI.getOperand(FIOperandNum).ChangeToRegister(VReg, false, false, true);
if (UseRR)
// Use [reg, reg] addrmode. Replace the immediate operand w/ the frame
// register. The offset is already handled in the vreg value.
MI.getOperand(FIOperandNum+1).ChangeToRegister(FrameReg, false, false,
false);
} else {
llvm_unreachable("Unexpected opcode!");
}
// Add predicate back if it's needed.
if (MI.isPredicable())
MIB.add(predOps(ARMCC::AL));
}
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