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llvm-mirror/lib/Target/ARM/ARMBaseInstrInfo.cpp
Dale Johannesen 8691bcbc2a Educate GetInstrSizeInBytes implementations that 
DBG_VALUE does not generate code.

llvm-svn: 100681
2010-04-07 19:51:44 +00:00

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//===- ARMBaseInstrInfo.cpp - ARM Instruction Information -------*- C++ -*-===//
//
// 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 Base ARM implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARMBaseInstrInfo.h"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMConstantPoolValue.h"
#include "ARMGenInstrInfo.inc"
#include "ARMMachineFunctionInfo.h"
#include "ARMRegisterInfo.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/GlobalValue.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
static cl::opt<bool>
EnableARM3Addr("enable-arm-3-addr-conv", cl::Hidden,
cl::desc("Enable ARM 2-addr to 3-addr conv"));
ARMBaseInstrInfo::ARMBaseInstrInfo(const ARMSubtarget& STI)
: TargetInstrInfoImpl(ARMInsts, array_lengthof(ARMInsts)),
Subtarget(STI) {
}
MachineInstr *
ARMBaseInstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables *LV) const {
// FIXME: Thumb2 support.
if (!EnableARM3Addr)
return NULL;
MachineInstr *MI = MBBI;
MachineFunction &MF = *MI->getParent()->getParent();
unsigned TSFlags = MI->getDesc().TSFlags;
bool isPre = false;
switch ((TSFlags & ARMII::IndexModeMask) >> ARMII::IndexModeShift) {
default: return NULL;
case ARMII::IndexModePre:
isPre = true;
break;
case ARMII::IndexModePost:
break;
}
// Try splitting an indexed load/store to an un-indexed one plus an add/sub
// operation.
unsigned MemOpc = getUnindexedOpcode(MI->getOpcode());
if (MemOpc == 0)
return NULL;
MachineInstr *UpdateMI = NULL;
MachineInstr *MemMI = NULL;
unsigned AddrMode = (TSFlags & ARMII::AddrModeMask);
const TargetInstrDesc &TID = MI->getDesc();
unsigned NumOps = TID.getNumOperands();
bool isLoad = !TID.mayStore();
const MachineOperand &WB = isLoad ? MI->getOperand(1) : MI->getOperand(0);
const MachineOperand &Base = MI->getOperand(2);
const MachineOperand &Offset = MI->getOperand(NumOps-3);
unsigned WBReg = WB.getReg();
unsigned BaseReg = Base.getReg();
unsigned OffReg = Offset.getReg();
unsigned OffImm = MI->getOperand(NumOps-2).getImm();
ARMCC::CondCodes Pred = (ARMCC::CondCodes)MI->getOperand(NumOps-1).getImm();
switch (AddrMode) {
default:
assert(false && "Unknown indexed op!");
return NULL;
case ARMII::AddrMode2: {
bool isSub = ARM_AM::getAM2Op(OffImm) == ARM_AM::sub;
unsigned Amt = ARM_AM::getAM2Offset(OffImm);
if (OffReg == 0) {
if (ARM_AM::getSOImmVal(Amt) == -1)
// Can't encode it in a so_imm operand. This transformation will
// add more than 1 instruction. Abandon!
return NULL;
UpdateMI = BuildMI(MF, MI->getDebugLoc(),
get(isSub ? ARM::SUBri : ARM::ADDri), WBReg)
.addReg(BaseReg).addImm(Amt)
.addImm(Pred).addReg(0).addReg(0);
} else if (Amt != 0) {
ARM_AM::ShiftOpc ShOpc = ARM_AM::getAM2ShiftOpc(OffImm);
unsigned SOOpc = ARM_AM::getSORegOpc(ShOpc, Amt);
UpdateMI = BuildMI(MF, MI->getDebugLoc(),
get(isSub ? ARM::SUBrs : ARM::ADDrs), WBReg)
.addReg(BaseReg).addReg(OffReg).addReg(0).addImm(SOOpc)
.addImm(Pred).addReg(0).addReg(0);
} else
UpdateMI = BuildMI(MF, MI->getDebugLoc(),
get(isSub ? ARM::SUBrr : ARM::ADDrr), WBReg)
.addReg(BaseReg).addReg(OffReg)
.addImm(Pred).addReg(0).addReg(0);
break;
}
case ARMII::AddrMode3 : {
bool isSub = ARM_AM::getAM3Op(OffImm) == ARM_AM::sub;
unsigned Amt = ARM_AM::getAM3Offset(OffImm);
if (OffReg == 0)
// Immediate is 8-bits. It's guaranteed to fit in a so_imm operand.
UpdateMI = BuildMI(MF, MI->getDebugLoc(),
get(isSub ? ARM::SUBri : ARM::ADDri), WBReg)
.addReg(BaseReg).addImm(Amt)
.addImm(Pred).addReg(0).addReg(0);
else
UpdateMI = BuildMI(MF, MI->getDebugLoc(),
get(isSub ? ARM::SUBrr : ARM::ADDrr), WBReg)
.addReg(BaseReg).addReg(OffReg)
.addImm(Pred).addReg(0).addReg(0);
break;
}
}
std::vector<MachineInstr*> NewMIs;
if (isPre) {
if (isLoad)
MemMI = BuildMI(MF, MI->getDebugLoc(),
get(MemOpc), MI->getOperand(0).getReg())
.addReg(WBReg).addReg(0).addImm(0).addImm(Pred);
else
MemMI = BuildMI(MF, MI->getDebugLoc(),
get(MemOpc)).addReg(MI->getOperand(1).getReg())
.addReg(WBReg).addReg(0).addImm(0).addImm(Pred);
NewMIs.push_back(MemMI);
NewMIs.push_back(UpdateMI);
} else {
if (isLoad)
MemMI = BuildMI(MF, MI->getDebugLoc(),
get(MemOpc), MI->getOperand(0).getReg())
.addReg(BaseReg).addReg(0).addImm(0).addImm(Pred);
else
MemMI = BuildMI(MF, MI->getDebugLoc(),
get(MemOpc)).addReg(MI->getOperand(1).getReg())
.addReg(BaseReg).addReg(0).addImm(0).addImm(Pred);
if (WB.isDead())
UpdateMI->getOperand(0).setIsDead();
NewMIs.push_back(UpdateMI);
NewMIs.push_back(MemMI);
}
// Transfer LiveVariables states, kill / dead info.
if (LV) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.getReg() &&
TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
unsigned Reg = MO.getReg();
LiveVariables::VarInfo &VI = LV->getVarInfo(Reg);
if (MO.isDef()) {
MachineInstr *NewMI = (Reg == WBReg) ? UpdateMI : MemMI;
if (MO.isDead())
LV->addVirtualRegisterDead(Reg, NewMI);
}
if (MO.isUse() && MO.isKill()) {
for (unsigned j = 0; j < 2; ++j) {
// Look at the two new MI's in reverse order.
MachineInstr *NewMI = NewMIs[j];
if (!NewMI->readsRegister(Reg))
continue;
LV->addVirtualRegisterKilled(Reg, NewMI);
if (VI.removeKill(MI))
VI.Kills.push_back(NewMI);
break;
}
}
}
}
}
MFI->insert(MBBI, NewMIs[1]);
MFI->insert(MBBI, NewMIs[0]);
return NewMIs[0];
}
// Branch analysis.
bool
ARMBaseInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const {
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin())
return false;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return false;
--I;
}
if (!isUnpredicatedTerminator(I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
unsigned LastOpc = LastInst->getOpcode();
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.
TBB = LastInst->getOperand(0).getMBB();
Cond.push_back(LastInst->getOperand(1));
Cond.push_back(LastInst->getOperand(2));
return false;
}
return true; // Can't handle indirect branch.
}
// Get the instruction before it if it is a terminator.
MachineInstr *SecondLastInst = I;
// 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.
unsigned SecondLastOpc = SecondLastInst->getOpcode();
if (isCondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
TBB = SecondLastInst->getOperand(0).getMBB();
Cond.push_back(SecondLastInst->getOperand(1));
Cond.push_back(SecondLastInst->getOperand(2));
FBB = LastInst->getOperand(0).getMBB();
return false;
}
// If the block ends with two unconditional branches, handle it. The second
// one is not executed, so remove it.
if (isUncondBranchOpcode(SecondLastOpc) && isUncondBranchOpcode(LastOpc)) {
TBB = SecondLastInst->getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return false;
}
// ...likewise if it ends with a branch table followed by an unconditional
// branch. The branch folder can create these, and we must get rid of them for
// correctness of Thumb constant islands.
if ((isJumpTableBranchOpcode(SecondLastOpc) ||
isIndirectBranchOpcode(SecondLastOpc)) &&
isUncondBranchOpcode(LastOpc)) {
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return true;
}
// Otherwise, can't handle this.
return true;
}
unsigned ARMBaseInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin()) return 0;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return 0;
--I;
}
if (!isUncondBranchOpcode(I->getOpcode()) &&
!isCondBranchOpcode(I->getOpcode()))
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) return 1;
--I;
if (!isCondBranchOpcode(I->getOpcode()))
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
unsigned
ARMBaseInstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond) const {
// FIXME this should probably have a DebugLoc argument
DebugLoc dl;
ARMFunctionInfo *AFI = MBB.getParent()->getInfo<ARMFunctionInfo>();
int BOpc = !AFI->isThumbFunction()
? ARM::B : (AFI->isThumb2Function() ? ARM::t2B : ARM::tB);
int BccOpc = !AFI->isThumbFunction()
? ARM::Bcc : (AFI->isThumb2Function() ? ARM::t2Bcc : ARM::tBcc);
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 2 || Cond.size() == 0) &&
"ARM branch conditions have two components!");
if (FBB == 0) {
if (Cond.empty()) // Unconditional branch?
BuildMI(&MBB, dl, get(BOpc)).addMBB(TBB);
else
BuildMI(&MBB, dl, get(BccOpc)).addMBB(TBB)
.addImm(Cond[0].getImm()).addReg(Cond[1].getReg());
return 1;
}
// Two-way conditional branch.
BuildMI(&MBB, dl, get(BccOpc)).addMBB(TBB)
.addImm(Cond[0].getImm()).addReg(Cond[1].getReg());
BuildMI(&MBB, dl, get(BOpc)).addMBB(FBB);
return 2;
}
bool ARMBaseInstrInfo::
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const {
ARMCC::CondCodes CC = (ARMCC::CondCodes)(int)Cond[0].getImm();
Cond[0].setImm(ARMCC::getOppositeCondition(CC));
return false;
}
bool ARMBaseInstrInfo::
PredicateInstruction(MachineInstr *MI,
const SmallVectorImpl<MachineOperand> &Pred) const {
unsigned Opc = MI->getOpcode();
if (isUncondBranchOpcode(Opc)) {
MI->setDesc(get(getMatchingCondBranchOpcode(Opc)));
MI->addOperand(MachineOperand::CreateImm(Pred[0].getImm()));
MI->addOperand(MachineOperand::CreateReg(Pred[1].getReg(), false));
return true;
}
int PIdx = MI->findFirstPredOperandIdx();
if (PIdx != -1) {
MachineOperand &PMO = MI->getOperand(PIdx);
PMO.setImm(Pred[0].getImm());
MI->getOperand(PIdx+1).setReg(Pred[1].getReg());
return true;
}
return false;
}
bool ARMBaseInstrInfo::
SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
const SmallVectorImpl<MachineOperand> &Pred2) const {
if (Pred1.size() > 2 || Pred2.size() > 2)
return false;
ARMCC::CondCodes CC1 = (ARMCC::CondCodes)Pred1[0].getImm();
ARMCC::CondCodes CC2 = (ARMCC::CondCodes)Pred2[0].getImm();
if (CC1 == CC2)
return true;
switch (CC1) {
default:
return false;
case ARMCC::AL:
return true;
case ARMCC::HS:
return CC2 == ARMCC::HI;
case ARMCC::LS:
return CC2 == ARMCC::LO || CC2 == ARMCC::EQ;
case ARMCC::GE:
return CC2 == ARMCC::GT;
case ARMCC::LE:
return CC2 == ARMCC::LT;
}
}
bool ARMBaseInstrInfo::DefinesPredicate(MachineInstr *MI,
std::vector<MachineOperand> &Pred) const {
// FIXME: This confuses implicit_def with optional CPSR def.
const TargetInstrDesc &TID = MI->getDesc();
if (!TID.getImplicitDefs() && !TID.hasOptionalDef())
return false;
bool Found = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.getReg() == ARM::CPSR) {
Pred.push_back(MO);
Found = true;
}
}
return Found;
}
/// isPredicable - Return true if the specified instruction can be predicated.
/// By default, this returns true for every instruction with a
/// PredicateOperand.
bool ARMBaseInstrInfo::isPredicable(MachineInstr *MI) const {
const TargetInstrDesc &TID = MI->getDesc();
if (!TID.isPredicable())
return false;
if ((TID.TSFlags & ARMII::DomainMask) == ARMII::DomainNEON) {
ARMFunctionInfo *AFI =
MI->getParent()->getParent()->getInfo<ARMFunctionInfo>();
return AFI->isThumb2Function();
}
return true;
}
/// FIXME: Works around a gcc miscompilation with -fstrict-aliasing.
DISABLE_INLINE
static unsigned getNumJTEntries(const std::vector<MachineJumpTableEntry> &JT,
unsigned JTI);
static unsigned getNumJTEntries(const std::vector<MachineJumpTableEntry> &JT,
unsigned JTI) {
assert(JTI < JT.size());
return JT[JTI].MBBs.size();
}
/// GetInstSize - Return the size of the specified MachineInstr.
///
unsigned ARMBaseInstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
const MachineBasicBlock &MBB = *MI->getParent();
const MachineFunction *MF = MBB.getParent();
const MCAsmInfo *MAI = MF->getTarget().getMCAsmInfo();
// Basic size info comes from the TSFlags field.
const TargetInstrDesc &TID = MI->getDesc();
unsigned TSFlags = TID.TSFlags;
unsigned Opc = MI->getOpcode();
switch ((TSFlags & ARMII::SizeMask) >> ARMII::SizeShift) {
default: {
// If this machine instr is an inline asm, measure it.
if (MI->getOpcode() == ARM::INLINEASM)
return getInlineAsmLength(MI->getOperand(0).getSymbolName(), *MAI);
if (MI->isLabel())
return 0;
switch (Opc) {
default:
llvm_unreachable("Unknown or unset size field for instr!");
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
case TargetOpcode::DBG_LABEL:
case TargetOpcode::EH_LABEL:
case TargetOpcode::DBG_VALUE:
return 0;
}
break;
}
case ARMII::Size8Bytes: return 8; // ARM instruction x 2.
case ARMII::Size4Bytes: return 4; // ARM / Thumb2 instruction.
case ARMII::Size2Bytes: return 2; // Thumb1 instruction.
case ARMII::SizeSpecial: {
switch (Opc) {
case ARM::CONSTPOOL_ENTRY:
// If this machine instr is a constant pool entry, its size is recorded as
// operand #2.
return MI->getOperand(2).getImm();
case ARM::Int_eh_sjlj_setjmp:
return 24;
case ARM::tInt_eh_sjlj_setjmp:
return 14;
case ARM::t2Int_eh_sjlj_setjmp:
return 14;
case ARM::BR_JTr:
case ARM::BR_JTm:
case ARM::BR_JTadd:
case ARM::tBR_JTr:
case ARM::t2BR_JT:
case ARM::t2TBB:
case ARM::t2TBH: {
// These are jumptable branches, i.e. a branch followed by an inlined
// jumptable. The size is 4 + 4 * number of entries. For TBB, each
// entry is one byte; TBH two byte each.
unsigned EntrySize = (Opc == ARM::t2TBB)
? 1 : ((Opc == ARM::t2TBH) ? 2 : 4);
unsigned NumOps = TID.getNumOperands();
MachineOperand JTOP =
MI->getOperand(NumOps - (TID.isPredicable() ? 3 : 2));
unsigned JTI = JTOP.getIndex();
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
assert(MJTI != 0);
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
assert(JTI < JT.size());
// Thumb instructions are 2 byte aligned, but JT entries are 4 byte
// 4 aligned. The assembler / linker may add 2 byte padding just before
// the JT entries. The size does not include this padding; the
// constant islands pass does separate bookkeeping for it.
// FIXME: If we know the size of the function is less than (1 << 16) *2
// bytes, we can use 16-bit entries instead. Then there won't be an
// alignment issue.
unsigned InstSize = (Opc == ARM::tBR_JTr || Opc == ARM::t2BR_JT) ? 2 : 4;
unsigned NumEntries = getNumJTEntries(JT, JTI);
if (Opc == ARM::t2TBB && (NumEntries & 1))
// Make sure the instruction that follows TBB is 2-byte aligned.
// FIXME: Constant island pass should insert an "ALIGN" instruction
// instead.
++NumEntries;
return NumEntries * EntrySize + InstSize;
}
default:
// Otherwise, pseudo-instruction sizes are zero.
return 0;
}
}
}
return 0; // Not reached
}
/// Return true if the instruction is a register to register move and
/// leave the source and dest operands in the passed parameters.
///
bool
ARMBaseInstrInfo::isMoveInstr(const MachineInstr &MI,
unsigned &SrcReg, unsigned &DstReg,
unsigned& SrcSubIdx, unsigned& DstSubIdx) const {
SrcSubIdx = DstSubIdx = 0; // No sub-registers.
switch (MI.getOpcode()) {
default: break;
case ARM::VMOVS:
case ARM::VMOVD:
case ARM::VMOVDneon:
case ARM::VMOVQ: {
SrcReg = MI.getOperand(1).getReg();
DstReg = MI.getOperand(0).getReg();
return true;
}
case ARM::MOVr:
case ARM::tMOVr:
case ARM::tMOVgpr2tgpr:
case ARM::tMOVtgpr2gpr:
case ARM::tMOVgpr2gpr:
case ARM::t2MOVr: {
assert(MI.getDesc().getNumOperands() >= 2 &&
MI.getOperand(0).isReg() &&
MI.getOperand(1).isReg() &&
"Invalid ARM MOV instruction");
SrcReg = MI.getOperand(1).getReg();
DstReg = MI.getOperand(0).getReg();
return true;
}
}
return false;
}
unsigned
ARMBaseInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
switch (MI->getOpcode()) {
default: break;
case ARM::LDR:
case ARM::t2LDRs: // FIXME: don't use t2LDRs to access frame.
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isReg() &&
MI->getOperand(3).isImm() &&
MI->getOperand(2).getReg() == 0 &&
MI->getOperand(3).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::t2LDRi12:
case ARM::tRestore:
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() &&
MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::VLDRD:
case ARM::VLDRS:
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() &&
MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
unsigned
ARMBaseInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
switch (MI->getOpcode()) {
default: break;
case ARM::STR:
case ARM::t2STRs: // FIXME: don't use t2STRs to access frame.
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isReg() &&
MI->getOperand(3).isImm() &&
MI->getOperand(2).getReg() == 0 &&
MI->getOperand(3).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::t2STRi12:
case ARM::tSpill:
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() &&
MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::VSTRD:
case ARM::VSTRS:
if (MI->getOperand(1).isFI() &&
MI->getOperand(2).isImm() &&
MI->getOperand(2).getImm() == 0) {
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
bool
ARMBaseInstrInfo::copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *DestRC,
const TargetRegisterClass *SrcRC) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
// tGPR is used sometimes in ARM instructions that need to avoid using
// certain registers. Just treat it as GPR here.
if (DestRC == ARM::tGPRRegisterClass)
DestRC = ARM::GPRRegisterClass;
if (SrcRC == ARM::tGPRRegisterClass)
SrcRC = ARM::GPRRegisterClass;
// Allow DPR / DPR_VFP2 / DPR_8 cross-class copies.
if (DestRC == ARM::DPR_8RegisterClass)
DestRC = ARM::DPR_VFP2RegisterClass;
if (SrcRC == ARM::DPR_8RegisterClass)
SrcRC = ARM::DPR_VFP2RegisterClass;
// Allow QPR / QPR_VFP2 / QPR_8 cross-class copies.
if (DestRC == ARM::QPR_VFP2RegisterClass ||
DestRC == ARM::QPR_8RegisterClass)
DestRC = ARM::QPRRegisterClass;
if (SrcRC == ARM::QPR_VFP2RegisterClass ||
SrcRC == ARM::QPR_8RegisterClass)
SrcRC = ARM::QPRRegisterClass;
// Disallow copies of unequal sizes.
if (DestRC != SrcRC && DestRC->getSize() != SrcRC->getSize())
return false;
if (DestRC == ARM::GPRRegisterClass) {
if (SrcRC == ARM::SPRRegisterClass)
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VMOVRS), DestReg)
.addReg(SrcReg));
else
AddDefaultCC(AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::MOVr),
DestReg).addReg(SrcReg)));
} else {
unsigned Opc;
if (DestRC == ARM::SPRRegisterClass)
Opc = (SrcRC == ARM::GPRRegisterClass ? ARM::VMOVSR : ARM::VMOVS);
else if (DestRC == ARM::DPRRegisterClass)
Opc = ARM::VMOVD;
else if (DestRC == ARM::DPR_VFP2RegisterClass ||
SrcRC == ARM::DPR_VFP2RegisterClass)
// Always use neon reg-reg move if source or dest is NEON-only regclass.
Opc = ARM::VMOVDneon;
else if (DestRC == ARM::QPRRegisterClass)
Opc = ARM::VMOVQ;
else
return false;
AddDefaultPred(BuildMI(MBB, I, DL, get(Opc), DestReg)
.addReg(SrcReg));
}
return true;
}
void ARMBaseInstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FI);
MachineMemOperand *MMO =
MF.getMachineMemOperand(PseudoSourceValue::getFixedStack(FI),
MachineMemOperand::MOStore, 0,
MFI.getObjectSize(FI),
Align);
// tGPR is used sometimes in ARM instructions that need to avoid using
// certain registers. Just treat it as GPR here.
if (RC == ARM::tGPRRegisterClass)
RC = ARM::GPRRegisterClass;
if (RC == ARM::GPRRegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::STR))
.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI).addReg(0).addImm(0).addMemOperand(MMO));
} else if (RC == ARM::DPRRegisterClass ||
RC == ARM::DPR_VFP2RegisterClass ||
RC == ARM::DPR_8RegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VSTRD))
.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI).addImm(0).addMemOperand(MMO));
} else if (RC == ARM::SPRRegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VSTRS))
.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI).addImm(0).addMemOperand(MMO));
} else {
assert((RC == ARM::QPRRegisterClass ||
RC == ARM::QPR_VFP2RegisterClass) && "Unknown regclass!");
// FIXME: Neon instructions should support predicates
if (Align >= 16 && (getRegisterInfo().canRealignStack(MF))) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VST1q))
.addFrameIndex(FI).addImm(128)
.addMemOperand(MMO)
.addReg(SrcReg, getKillRegState(isKill)));
} else {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VSTMQ)).
addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FI)
.addImm(ARM_AM::getAM5Opc(ARM_AM::ia, 4))
.addMemOperand(MMO));
}
}
}
void ARMBaseInstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, int FI,
const TargetRegisterClass *RC) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FI);
MachineMemOperand *MMO =
MF.getMachineMemOperand(PseudoSourceValue::getFixedStack(FI),
MachineMemOperand::MOLoad, 0,
MFI.getObjectSize(FI),
Align);
// tGPR is used sometimes in ARM instructions that need to avoid using
// certain registers. Just treat it as GPR here.
if (RC == ARM::tGPRRegisterClass)
RC = ARM::GPRRegisterClass;
if (RC == ARM::GPRRegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::LDR), DestReg)
.addFrameIndex(FI).addReg(0).addImm(0).addMemOperand(MMO));
} else if (RC == ARM::DPRRegisterClass ||
RC == ARM::DPR_VFP2RegisterClass ||
RC == ARM::DPR_8RegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VLDRD), DestReg)
.addFrameIndex(FI).addImm(0).addMemOperand(MMO));
} else if (RC == ARM::SPRRegisterClass) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VLDRS), DestReg)
.addFrameIndex(FI).addImm(0).addMemOperand(MMO));
} else {
assert((RC == ARM::QPRRegisterClass ||
RC == ARM::QPR_VFP2RegisterClass ||
RC == ARM::QPR_8RegisterClass) && "Unknown regclass!");
if (Align >= 16
&& (getRegisterInfo().canRealignStack(MF))) {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VLD1q), DestReg)
.addFrameIndex(FI).addImm(128)
.addMemOperand(MMO));
} else {
AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::VLDMQ), DestReg)
.addFrameIndex(FI)
.addImm(ARM_AM::getAM5Opc(ARM_AM::ia, 4))
.addMemOperand(MMO));
}
}
}
MachineInstr *ARMBaseInstrInfo::
foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
const SmallVectorImpl<unsigned> &Ops, int FI) const {
if (Ops.size() != 1) return NULL;
unsigned OpNum = Ops[0];
unsigned Opc = MI->getOpcode();
MachineInstr *NewMI = NULL;
if (Opc == ARM::MOVr || Opc == ARM::t2MOVr) {
// If it is updating CPSR, then it cannot be folded.
if (MI->getOperand(4).getReg() == ARM::CPSR && !MI->getOperand(4).isDead())
return NULL;
unsigned Pred = MI->getOperand(2).getImm();
unsigned PredReg = MI->getOperand(3).getReg();
if (OpNum == 0) { // move -> store
unsigned SrcReg = MI->getOperand(1).getReg();
unsigned SrcSubReg = MI->getOperand(1).getSubReg();
bool isKill = MI->getOperand(1).isKill();
bool isUndef = MI->getOperand(1).isUndef();
if (Opc == ARM::MOVr)
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::STR))
.addReg(SrcReg,
getKillRegState(isKill) | getUndefRegState(isUndef),
SrcSubReg)
.addFrameIndex(FI).addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
else // ARM::t2MOVr
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::t2STRi12))
.addReg(SrcReg,
getKillRegState(isKill) | getUndefRegState(isUndef),
SrcSubReg)
.addFrameIndex(FI).addImm(0).addImm(Pred).addReg(PredReg);
} else { // move -> load
unsigned DstReg = MI->getOperand(0).getReg();
unsigned DstSubReg = MI->getOperand(0).getSubReg();
bool isDead = MI->getOperand(0).isDead();
bool isUndef = MI->getOperand(0).isUndef();
if (Opc == ARM::MOVr)
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::LDR))
.addReg(DstReg,
RegState::Define |
getDeadRegState(isDead) |
getUndefRegState(isUndef), DstSubReg)
.addFrameIndex(FI).addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
else // ARM::t2MOVr
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::t2LDRi12))
.addReg(DstReg,
RegState::Define |
getDeadRegState(isDead) |
getUndefRegState(isUndef), DstSubReg)
.addFrameIndex(FI).addImm(0).addImm(Pred).addReg(PredReg);
}
} else if (Opc == ARM::tMOVgpr2gpr ||
Opc == ARM::tMOVtgpr2gpr ||
Opc == ARM::tMOVgpr2tgpr) {
if (OpNum == 0) { // move -> store
unsigned SrcReg = MI->getOperand(1).getReg();
unsigned SrcSubReg = MI->getOperand(1).getSubReg();
bool isKill = MI->getOperand(1).isKill();
bool isUndef = MI->getOperand(1).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::t2STRi12))
.addReg(SrcReg,
getKillRegState(isKill) | getUndefRegState(isUndef),
SrcSubReg)
.addFrameIndex(FI).addImm(0).addImm(ARMCC::AL).addReg(0);
} else { // move -> load
unsigned DstReg = MI->getOperand(0).getReg();
unsigned DstSubReg = MI->getOperand(0).getSubReg();
bool isDead = MI->getOperand(0).isDead();
bool isUndef = MI->getOperand(0).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::t2LDRi12))
.addReg(DstReg,
RegState::Define |
getDeadRegState(isDead) |
getUndefRegState(isUndef),
DstSubReg)
.addFrameIndex(FI).addImm(0).addImm(ARMCC::AL).addReg(0);
}
} else if (Opc == ARM::VMOVS) {
unsigned Pred = MI->getOperand(2).getImm();
unsigned PredReg = MI->getOperand(3).getReg();
if (OpNum == 0) { // move -> store
unsigned SrcReg = MI->getOperand(1).getReg();
unsigned SrcSubReg = MI->getOperand(1).getSubReg();
bool isKill = MI->getOperand(1).isKill();
bool isUndef = MI->getOperand(1).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::VSTRS))
.addReg(SrcReg, getKillRegState(isKill) | getUndefRegState(isUndef),
SrcSubReg)
.addFrameIndex(FI)
.addImm(0).addImm(Pred).addReg(PredReg);
} else { // move -> load
unsigned DstReg = MI->getOperand(0).getReg();
unsigned DstSubReg = MI->getOperand(0).getSubReg();
bool isDead = MI->getOperand(0).isDead();
bool isUndef = MI->getOperand(0).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::VLDRS))
.addReg(DstReg,
RegState::Define |
getDeadRegState(isDead) |
getUndefRegState(isUndef),
DstSubReg)
.addFrameIndex(FI).addImm(0).addImm(Pred).addReg(PredReg);
}
}
else if (Opc == ARM::VMOVD) {
unsigned Pred = MI->getOperand(2).getImm();
unsigned PredReg = MI->getOperand(3).getReg();
if (OpNum == 0) { // move -> store
unsigned SrcReg = MI->getOperand(1).getReg();
unsigned SrcSubReg = MI->getOperand(1).getSubReg();
bool isKill = MI->getOperand(1).isKill();
bool isUndef = MI->getOperand(1).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::VSTRD))
.addReg(SrcReg,
getKillRegState(isKill) | getUndefRegState(isUndef),
SrcSubReg)
.addFrameIndex(FI).addImm(0).addImm(Pred).addReg(PredReg);
} else { // move -> load
unsigned DstReg = MI->getOperand(0).getReg();
unsigned DstSubReg = MI->getOperand(0).getSubReg();
bool isDead = MI->getOperand(0).isDead();
bool isUndef = MI->getOperand(0).isUndef();
NewMI = BuildMI(MF, MI->getDebugLoc(), get(ARM::VLDRD))
.addReg(DstReg,
RegState::Define |
getDeadRegState(isDead) |
getUndefRegState(isUndef),
DstSubReg)
.addFrameIndex(FI).addImm(0).addImm(Pred).addReg(PredReg);
}
}
return NewMI;
}
MachineInstr*
ARMBaseInstrInfo::foldMemoryOperandImpl(MachineFunction &MF,
MachineInstr* MI,
const SmallVectorImpl<unsigned> &Ops,
MachineInstr* LoadMI) const {
// FIXME
return 0;
}
bool
ARMBaseInstrInfo::canFoldMemoryOperand(const MachineInstr *MI,
const SmallVectorImpl<unsigned> &Ops) const {
if (Ops.size() != 1) return false;
unsigned Opc = MI->getOpcode();
if (Opc == ARM::MOVr || Opc == ARM::t2MOVr) {
// If it is updating CPSR, then it cannot be folded.
return MI->getOperand(4).getReg() != ARM::CPSR ||
MI->getOperand(4).isDead();
} else if (Opc == ARM::tMOVgpr2gpr ||
Opc == ARM::tMOVtgpr2gpr ||
Opc == ARM::tMOVgpr2tgpr) {
return true;
} else if (Opc == ARM::VMOVS || Opc == ARM::VMOVD) {
return true;
} else if (Opc == ARM::VMOVDneon || Opc == ARM::VMOVQ) {
return false; // FIXME
}
return false;
}
/// Create a copy of a const pool value. Update CPI to the new index and return
/// the label UID.
static unsigned duplicateCPV(MachineFunction &MF, unsigned &CPI) {
MachineConstantPool *MCP = MF.getConstantPool();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPI];
assert(MCPE.isMachineConstantPoolEntry() &&
"Expecting a machine constantpool entry!");
ARMConstantPoolValue *ACPV =
static_cast<ARMConstantPoolValue*>(MCPE.Val.MachineCPVal);
unsigned PCLabelId = AFI->createConstPoolEntryUId();
ARMConstantPoolValue *NewCPV = 0;
if (ACPV->isGlobalValue())
NewCPV = new ARMConstantPoolValue(ACPV->getGV(), PCLabelId,
ARMCP::CPValue, 4);
else if (ACPV->isExtSymbol())
NewCPV = new ARMConstantPoolValue(MF.getFunction()->getContext(),
ACPV->getSymbol(), PCLabelId, 4);
else if (ACPV->isBlockAddress())
NewCPV = new ARMConstantPoolValue(ACPV->getBlockAddress(), PCLabelId,
ARMCP::CPBlockAddress, 4);
else
llvm_unreachable("Unexpected ARM constantpool value type!!");
CPI = MCP->getConstantPoolIndex(NewCPV, MCPE.getAlignment());
return PCLabelId;
}
void ARMBaseInstrInfo::
reMaterialize(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DestReg, unsigned SubIdx,
const MachineInstr *Orig,
const TargetRegisterInfo *TRI) const {
if (SubIdx && TargetRegisterInfo::isPhysicalRegister(DestReg)) {
DestReg = TRI->getSubReg(DestReg, SubIdx);
SubIdx = 0;
}
unsigned Opcode = Orig->getOpcode();
switch (Opcode) {
default: {
MachineInstr *MI = MBB.getParent()->CloneMachineInstr(Orig);
MI->getOperand(0).setReg(DestReg);
MBB.insert(I, MI);
break;
}
case ARM::tLDRpci_pic:
case ARM::t2LDRpci_pic: {
MachineFunction &MF = *MBB.getParent();
unsigned CPI = Orig->getOperand(1).getIndex();
unsigned PCLabelId = duplicateCPV(MF, CPI);
MachineInstrBuilder MIB = BuildMI(MBB, I, Orig->getDebugLoc(), get(Opcode),
DestReg)
.addConstantPoolIndex(CPI).addImm(PCLabelId);
(*MIB).setMemRefs(Orig->memoperands_begin(), Orig->memoperands_end());
break;
}
}
MachineInstr *NewMI = prior(I);
NewMI->getOperand(0).setSubReg(SubIdx);
}
MachineInstr *
ARMBaseInstrInfo::duplicate(MachineInstr *Orig, MachineFunction &MF) const {
MachineInstr *MI = TargetInstrInfoImpl::duplicate(Orig, MF);
switch(Orig->getOpcode()) {
case ARM::tLDRpci_pic:
case ARM::t2LDRpci_pic: {
unsigned CPI = Orig->getOperand(1).getIndex();
unsigned PCLabelId = duplicateCPV(MF, CPI);
Orig->getOperand(1).setIndex(CPI);
Orig->getOperand(2).setImm(PCLabelId);
break;
}
}
return MI;
}
bool ARMBaseInstrInfo::produceSameValue(const MachineInstr *MI0,
const MachineInstr *MI1) const {
int Opcode = MI0->getOpcode();
if (Opcode == ARM::t2LDRpci ||
Opcode == ARM::t2LDRpci_pic ||
Opcode == ARM::tLDRpci ||
Opcode == ARM::tLDRpci_pic) {
if (MI1->getOpcode() != Opcode)
return false;
if (MI0->getNumOperands() != MI1->getNumOperands())
return false;
const MachineOperand &MO0 = MI0->getOperand(1);
const MachineOperand &MO1 = MI1->getOperand(1);
if (MO0.getOffset() != MO1.getOffset())
return false;
const MachineFunction *MF = MI0->getParent()->getParent();
const MachineConstantPool *MCP = MF->getConstantPool();
int CPI0 = MO0.getIndex();
int CPI1 = MO1.getIndex();
const MachineConstantPoolEntry &MCPE0 = MCP->getConstants()[CPI0];
const MachineConstantPoolEntry &MCPE1 = MCP->getConstants()[CPI1];
ARMConstantPoolValue *ACPV0 =
static_cast<ARMConstantPoolValue*>(MCPE0.Val.MachineCPVal);
ARMConstantPoolValue *ACPV1 =
static_cast<ARMConstantPoolValue*>(MCPE1.Val.MachineCPVal);
return ACPV0->hasSameValue(ACPV1);
}
return MI0->isIdenticalTo(MI1, MachineInstr::IgnoreVRegDefs);
}
/// getInstrPredicate - If instruction is predicated, returns its predicate
/// condition, otherwise returns AL. It also returns the condition code
/// register by reference.
ARMCC::CondCodes
llvm::getInstrPredicate(const MachineInstr *MI, unsigned &PredReg) {
int PIdx = MI->findFirstPredOperandIdx();
if (PIdx == -1) {
PredReg = 0;
return ARMCC::AL;
}
PredReg = MI->getOperand(PIdx+1).getReg();
return (ARMCC::CondCodes)MI->getOperand(PIdx).getImm();
}
int llvm::getMatchingCondBranchOpcode(int Opc) {
if (Opc == ARM::B)
return ARM::Bcc;
else if (Opc == ARM::tB)
return ARM::tBcc;
else if (Opc == ARM::t2B)
return ARM::t2Bcc;
llvm_unreachable("Unknown unconditional branch opcode!");
return 0;
}
void llvm::emitARMRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg, int NumBytes,
ARMCC::CondCodes Pred, unsigned PredReg,
const ARMBaseInstrInfo &TII) {
bool isSub = NumBytes < 0;
if (isSub) NumBytes = -NumBytes;
while (NumBytes) {
unsigned RotAmt = ARM_AM::getSOImmValRotate(NumBytes);
unsigned ThisVal = NumBytes & ARM_AM::rotr32(0xFF, RotAmt);
assert(ThisVal && "Didn't extract field correctly");
// We will handle these bits from offset, clear them.
NumBytes &= ~ThisVal;
assert(ARM_AM::getSOImmVal(ThisVal) != -1 && "Bit extraction didn't work?");
// Build the new ADD / SUB.
unsigned Opc = isSub ? ARM::SUBri : ARM::ADDri;
BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
.addReg(BaseReg, RegState::Kill).addImm(ThisVal)
.addImm((unsigned)Pred).addReg(PredReg).addReg(0);
BaseReg = DestReg;
}
}
bool llvm::rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII) {
unsigned Opcode = MI.getOpcode();
const TargetInstrDesc &Desc = MI.getDesc();
unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
bool isSub = false;
// Memory operands in inline assembly always use AddrMode2.
if (Opcode == ARM::INLINEASM)
AddrMode = ARMII::AddrMode2;
if (Opcode == ARM::ADDri) {
Offset += MI.getOperand(FrameRegIdx+1).getImm();
if (Offset == 0) {
// Turn it into a move.
MI.setDesc(TII.get(ARM::MOVr));
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
MI.RemoveOperand(FrameRegIdx+1);
Offset = 0;
return true;
} else if (Offset < 0) {
Offset = -Offset;
isSub = true;
MI.setDesc(TII.get(ARM::SUBri));
}
// Common case: small offset, fits into instruction.
if (ARM_AM::getSOImmVal(Offset) != -1) {
// Replace the FrameIndex with sp / fp
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
Offset = 0;
return true;
}
// Otherwise, pull as much of the immedidate into this ADDri/SUBri
// as possible.
unsigned RotAmt = ARM_AM::getSOImmValRotate(Offset);
unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xFF, RotAmt);
// We will handle these bits from offset, clear them.
Offset &= ~ThisImmVal;
// Get the properly encoded SOImmVal field.
assert(ARM_AM::getSOImmVal(ThisImmVal) != -1 &&
"Bit extraction didn't work?");
MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
} else {
unsigned ImmIdx = 0;
int InstrOffs = 0;
unsigned NumBits = 0;
unsigned Scale = 1;
switch (AddrMode) {
case ARMII::AddrMode2: {
ImmIdx = FrameRegIdx+2;
InstrOffs = ARM_AM::getAM2Offset(MI.getOperand(ImmIdx).getImm());
if (ARM_AM::getAM2Op(MI.getOperand(ImmIdx).getImm()) == ARM_AM::sub)
InstrOffs *= -1;
NumBits = 12;
break;
}
case ARMII::AddrMode3: {
ImmIdx = FrameRegIdx+2;
InstrOffs = ARM_AM::getAM3Offset(MI.getOperand(ImmIdx).getImm());
if (ARM_AM::getAM3Op(MI.getOperand(ImmIdx).getImm()) == ARM_AM::sub)
InstrOffs *= -1;
NumBits = 8;
break;
}
case ARMII::AddrMode4:
case ARMII::AddrMode6:
// Can't fold any offset even if it's zero.
return false;
case ARMII::AddrMode5: {
ImmIdx = FrameRegIdx+1;
InstrOffs = ARM_AM::getAM5Offset(MI.getOperand(ImmIdx).getImm());
if (ARM_AM::getAM5Op(MI.getOperand(ImmIdx).getImm()) == ARM_AM::sub)
InstrOffs *= -1;
NumBits = 8;
Scale = 4;
break;
}
default:
llvm_unreachable("Unsupported addressing mode!");
break;
}
Offset += InstrOffs * Scale;
assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
if (Offset < 0) {
Offset = -Offset;
isSub = true;
}
// Attempt to fold address comp. if opcode has offset bits
if (NumBits > 0) {
// 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 sp
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
if (isSub)
ImmedOffset |= 1 << NumBits;
ImmOp.ChangeToImmediate(ImmedOffset);
Offset = 0;
return true;
}
// Otherwise, it didn't fit. Pull in what we can to simplify the immed.
ImmedOffset = ImmedOffset & Mask;
if (isSub)
ImmedOffset |= 1 << NumBits;
ImmOp.ChangeToImmediate(ImmedOffset);
Offset &= ~(Mask*Scale);
}
}
Offset = (isSub) ? -Offset : Offset;
return Offset == 0;
}
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