1 //===-- Thumb2InstrInfo.cpp - Thumb-2 Instruction Information -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the Thumb-2 implementation of the TargetInstrInfo class.
12 //===----------------------------------------------------------------------===//
14 #include "Thumb2InstrInfo.h"
16 #include "ARMConstantPoolValue.h"
17 #include "ARMMachineFunctionInfo.h"
18 #include "Thumb2InstrInfo.h"
19 #include "MCTargetDesc/ARMAddressingModes.h"
20 #include "llvm/CodeGen/MachineFrameInfo.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/CodeGen/MachineMemOperand.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/MC/MCInst.h"
25 #include "llvm/Support/CommandLine.h"
30 OldT2IfCvt("old-thumb2-ifcvt", cl::Hidden,
31 cl::desc("Use old-style Thumb2 if-conversion heuristics"),
34 Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI)
35 : ARMBaseInstrInfo(STI), RI(*this, STI) {
38 /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
39 void Thumb2InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
40 NopInst.setOpcode(ARM::tNOP);
41 NopInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
42 NopInst.addOperand(MCOperand::CreateReg(0));
45 unsigned Thumb2InstrInfo::getUnindexedOpcode(unsigned Opc) const {
51 Thumb2InstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
52 MachineBasicBlock *NewDest) const {
53 MachineBasicBlock *MBB = Tail->getParent();
54 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
55 if (!AFI->hasITBlocks()) {
56 TargetInstrInfoImpl::ReplaceTailWithBranchTo(Tail, NewDest);
60 // If the first instruction of Tail is predicated, we may have to update
61 // the IT instruction.
63 ARMCC::CondCodes CC = llvm::getInstrPredicate(Tail, PredReg);
64 MachineBasicBlock::iterator MBBI = Tail;
66 // Expecting at least the t2IT instruction before it.
69 // Actually replace the tail.
70 TargetInstrInfoImpl::ReplaceTailWithBranchTo(Tail, NewDest);
73 if (CC != ARMCC::AL) {
74 MachineBasicBlock::iterator E = MBB->begin();
75 unsigned Count = 4; // At most 4 instructions in an IT block.
76 while (Count && MBBI != E) {
77 if (MBBI->isDebugValue()) {
81 if (MBBI->getOpcode() == ARM::t2IT) {
82 unsigned Mask = MBBI->getOperand(1).getImm();
84 MBBI->eraseFromParent();
86 unsigned MaskOn = 1 << Count;
87 unsigned MaskOff = ~(MaskOn - 1);
88 MBBI->getOperand(1).setImm((Mask & MaskOff) | MaskOn);
96 // Ctrl flow can reach here if branch folding is run before IT block
102 Thumb2InstrInfo::isLegalToSplitMBBAt(MachineBasicBlock &MBB,
103 MachineBasicBlock::iterator MBBI) const {
104 while (MBBI->isDebugValue()) {
106 if (MBBI == MBB.end())
110 unsigned PredReg = 0;
111 return llvm::getITInstrPredicate(MBBI, PredReg) == ARMCC::AL;
114 void Thumb2InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
115 MachineBasicBlock::iterator I, DebugLoc DL,
116 unsigned DestReg, unsigned SrcReg,
117 bool KillSrc) const {
118 // Handle SPR, DPR, and QPR copies.
119 if (!ARM::GPRRegClass.contains(DestReg, SrcReg))
120 return ARMBaseInstrInfo::copyPhysReg(MBB, I, DL, DestReg, SrcReg, KillSrc);
122 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::tMOVr), DestReg)
123 .addReg(SrcReg, getKillRegState(KillSrc)));
126 void Thumb2InstrInfo::
127 storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
128 unsigned SrcReg, bool isKill, int FI,
129 const TargetRegisterClass *RC,
130 const TargetRegisterInfo *TRI) const {
131 if (RC == ARM::GPRRegisterClass || RC == ARM::tGPRRegisterClass ||
132 RC == ARM::tcGPRRegisterClass || RC == ARM::rGPRRegisterClass ||
133 RC == ARM::GPRnopcRegisterClass) {
135 if (I != MBB.end()) DL = I->getDebugLoc();
137 MachineFunction &MF = *MBB.getParent();
138 MachineFrameInfo &MFI = *MF.getFrameInfo();
139 MachineMemOperand *MMO =
140 MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
141 MachineMemOperand::MOStore,
142 MFI.getObjectSize(FI),
143 MFI.getObjectAlignment(FI));
144 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2STRi12))
145 .addReg(SrcReg, getKillRegState(isKill))
146 .addFrameIndex(FI).addImm(0).addMemOperand(MMO));
150 ARMBaseInstrInfo::storeRegToStackSlot(MBB, I, SrcReg, isKill, FI, RC, TRI);
153 void Thumb2InstrInfo::
154 loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
155 unsigned DestReg, int FI,
156 const TargetRegisterClass *RC,
157 const TargetRegisterInfo *TRI) const {
158 if (RC == ARM::GPRRegisterClass || RC == ARM::tGPRRegisterClass ||
159 RC == ARM::tcGPRRegisterClass || RC == ARM::rGPRRegisterClass ||
160 RC == ARM::GPRnopcRegisterClass) {
162 if (I != MBB.end()) DL = I->getDebugLoc();
164 MachineFunction &MF = *MBB.getParent();
165 MachineFrameInfo &MFI = *MF.getFrameInfo();
166 MachineMemOperand *MMO =
167 MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
168 MachineMemOperand::MOLoad,
169 MFI.getObjectSize(FI),
170 MFI.getObjectAlignment(FI));
171 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2LDRi12), DestReg)
172 .addFrameIndex(FI).addImm(0).addMemOperand(MMO));
176 ARMBaseInstrInfo::loadRegFromStackSlot(MBB, I, DestReg, FI, RC, TRI);
179 void llvm::emitT2RegPlusImmediate(MachineBasicBlock &MBB,
180 MachineBasicBlock::iterator &MBBI, DebugLoc dl,
181 unsigned DestReg, unsigned BaseReg, int NumBytes,
182 ARMCC::CondCodes Pred, unsigned PredReg,
183 const ARMBaseInstrInfo &TII, unsigned MIFlags) {
184 bool isSub = NumBytes < 0;
185 if (isSub) NumBytes = -NumBytes;
187 // If profitable, use a movw or movt to materialize the offset.
188 // FIXME: Use the scavenger to grab a scratch register.
189 if (DestReg != ARM::SP && DestReg != BaseReg &&
191 ARM_AM::getT2SOImmVal(NumBytes) == -1) {
193 if (NumBytes < 65536) {
194 // Use a movw to materialize the 16-bit constant.
195 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), DestReg)
197 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
199 } else if ((NumBytes & 0xffff) == 0) {
200 // Use a movt to materialize the 32-bit constant.
201 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVTi16), DestReg)
203 .addImm(NumBytes >> 16)
204 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
210 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), DestReg)
211 .addReg(BaseReg, RegState::Kill)
212 .addReg(DestReg, RegState::Kill)
213 .addImm((unsigned)Pred).addReg(PredReg).addReg(0)
214 .setMIFlags(MIFlags);
216 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2ADDrr), DestReg)
217 .addReg(DestReg, RegState::Kill)
218 .addReg(BaseReg, RegState::Kill)
219 .addImm((unsigned)Pred).addReg(PredReg).addReg(0)
220 .setMIFlags(MIFlags);
227 unsigned ThisVal = NumBytes;
229 if (DestReg == ARM::SP && BaseReg != ARM::SP) {
230 // mov sp, rn. Note t2MOVr cannot be used.
231 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr),DestReg)
232 .addReg(BaseReg).setMIFlags(MIFlags));
237 bool HasCCOut = true;
238 if (BaseReg == ARM::SP) {
240 if (DestReg == ARM::SP && (ThisVal < ((1 << 7)-1) * 4)) {
241 assert((ThisVal & 3) == 0 && "Stack update is not multiple of 4?");
242 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
243 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
244 .addReg(BaseReg).addImm(ThisVal/4).setMIFlags(MIFlags));
249 // sub rd, sp, so_imm
250 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
251 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
254 // FIXME: Move this to ARMAddressingModes.h?
255 unsigned RotAmt = CountLeadingZeros_32(ThisVal);
256 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
257 NumBytes &= ~ThisVal;
258 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
259 "Bit extraction didn't work?");
262 assert(DestReg != ARM::SP && BaseReg != ARM::SP);
263 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
264 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
266 } else if (ThisVal < 4096) {
267 Opc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
271 // FIXME: Move this to ARMAddressingModes.h?
272 unsigned RotAmt = CountLeadingZeros_32(ThisVal);
273 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
274 NumBytes &= ~ThisVal;
275 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
276 "Bit extraction didn't work?");
280 // Build the new ADD / SUB.
281 MachineInstrBuilder MIB =
282 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
283 .addReg(BaseReg, RegState::Kill)
284 .addImm(ThisVal)).setMIFlags(MIFlags);
293 negativeOffsetOpcode(unsigned opcode)
296 case ARM::t2LDRi12: return ARM::t2LDRi8;
297 case ARM::t2LDRHi12: return ARM::t2LDRHi8;
298 case ARM::t2LDRBi12: return ARM::t2LDRBi8;
299 case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
300 case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
301 case ARM::t2STRi12: return ARM::t2STRi8;
302 case ARM::t2STRBi12: return ARM::t2STRBi8;
303 case ARM::t2STRHi12: return ARM::t2STRHi8;
323 positiveOffsetOpcode(unsigned opcode)
326 case ARM::t2LDRi8: return ARM::t2LDRi12;
327 case ARM::t2LDRHi8: return ARM::t2LDRHi12;
328 case ARM::t2LDRBi8: return ARM::t2LDRBi12;
329 case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
330 case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
331 case ARM::t2STRi8: return ARM::t2STRi12;
332 case ARM::t2STRBi8: return ARM::t2STRBi12;
333 case ARM::t2STRHi8: return ARM::t2STRHi12;
338 case ARM::t2LDRSHi12:
339 case ARM::t2LDRSBi12:
353 immediateOffsetOpcode(unsigned opcode)
356 case ARM::t2LDRs: return ARM::t2LDRi12;
357 case ARM::t2LDRHs: return ARM::t2LDRHi12;
358 case ARM::t2LDRBs: return ARM::t2LDRBi12;
359 case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
360 case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
361 case ARM::t2STRs: return ARM::t2STRi12;
362 case ARM::t2STRBs: return ARM::t2STRBi12;
363 case ARM::t2STRHs: return ARM::t2STRHi12;
368 case ARM::t2LDRSHi12:
369 case ARM::t2LDRSBi12:
390 bool llvm::rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
391 unsigned FrameReg, int &Offset,
392 const ARMBaseInstrInfo &TII) {
393 unsigned Opcode = MI.getOpcode();
394 const MCInstrDesc &Desc = MI.getDesc();
395 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
398 // Memory operands in inline assembly always use AddrModeT2_i12.
399 if (Opcode == ARM::INLINEASM)
400 AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
402 if (Opcode == ARM::t2ADDri || Opcode == ARM::t2ADDri12) {
403 Offset += MI.getOperand(FrameRegIdx+1).getImm();
406 if (Offset == 0 && getInstrPredicate(&MI, PredReg) == ARMCC::AL) {
407 // Turn it into a move.
408 MI.setDesc(TII.get(ARM::tMOVr));
409 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
410 // Remove offset and remaining explicit predicate operands.
411 do MI.RemoveOperand(FrameRegIdx+1);
412 while (MI.getNumOperands() > FrameRegIdx+1);
413 MachineInstrBuilder MIB(&MI);
418 bool HasCCOut = Opcode != ARM::t2ADDri12;
423 MI.setDesc(TII.get(ARM::t2SUBri));
425 MI.setDesc(TII.get(ARM::t2ADDri));
428 // Common case: small offset, fits into instruction.
429 if (ARM_AM::getT2SOImmVal(Offset) != -1) {
430 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
431 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
432 // Add cc_out operand if the original instruction did not have one.
434 MI.addOperand(MachineOperand::CreateReg(0, false));
438 // Another common case: imm12.
440 (!HasCCOut || MI.getOperand(MI.getNumOperands()-1).getReg() == 0)) {
441 unsigned NewOpc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
442 MI.setDesc(TII.get(NewOpc));
443 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
444 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
445 // Remove the cc_out operand.
447 MI.RemoveOperand(MI.getNumOperands()-1);
452 // Otherwise, extract 8 adjacent bits from the immediate into this
454 unsigned RotAmt = CountLeadingZeros_32(Offset);
455 unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
457 // We will handle these bits from offset, clear them.
458 Offset &= ~ThisImmVal;
460 assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
461 "Bit extraction didn't work?");
462 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
463 // Add cc_out operand if the original instruction did not have one.
465 MI.addOperand(MachineOperand::CreateReg(0, false));
469 // AddrMode4 and AddrMode6 cannot handle any offset.
470 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
473 // AddrModeT2_so cannot handle any offset. If there is no offset
474 // register then we change to an immediate version.
475 unsigned NewOpc = Opcode;
476 if (AddrMode == ARMII::AddrModeT2_so) {
477 unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
478 if (OffsetReg != 0) {
479 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
483 MI.RemoveOperand(FrameRegIdx+1);
484 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
485 NewOpc = immediateOffsetOpcode(Opcode);
486 AddrMode = ARMII::AddrModeT2_i12;
489 unsigned NumBits = 0;
491 if (AddrMode == ARMII::AddrModeT2_i8 || AddrMode == ARMII::AddrModeT2_i12) {
492 // i8 supports only negative, and i12 supports only positive, so
493 // based on Offset sign convert Opcode to the appropriate
495 Offset += MI.getOperand(FrameRegIdx+1).getImm();
497 NewOpc = negativeOffsetOpcode(Opcode);
502 NewOpc = positiveOffsetOpcode(Opcode);
505 } else if (AddrMode == ARMII::AddrMode5) {
507 const MachineOperand &OffOp = MI.getOperand(FrameRegIdx+1);
508 int InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
509 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
513 Offset += InstrOffs * 4;
514 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
520 llvm_unreachable("Unsupported addressing mode!");
523 if (NewOpc != Opcode)
524 MI.setDesc(TII.get(NewOpc));
526 MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
528 // Attempt to fold address computation
529 // Common case: small offset, fits into instruction.
530 int ImmedOffset = Offset / Scale;
531 unsigned Mask = (1 << NumBits) - 1;
532 if ((unsigned)Offset <= Mask * Scale) {
533 // Replace the FrameIndex with fp/sp
534 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
536 if (AddrMode == ARMII::AddrMode5)
537 // FIXME: Not consistent.
538 ImmedOffset |= 1 << NumBits;
540 ImmedOffset = -ImmedOffset;
542 ImmOp.ChangeToImmediate(ImmedOffset);
547 // Otherwise, offset doesn't fit. Pull in what we can to simplify
548 ImmedOffset = ImmedOffset & Mask;
550 if (AddrMode == ARMII::AddrMode5)
551 // FIXME: Not consistent.
552 ImmedOffset |= 1 << NumBits;
554 ImmedOffset = -ImmedOffset;
555 if (ImmedOffset == 0)
556 // Change the opcode back if the encoded offset is zero.
557 MI.setDesc(TII.get(positiveOffsetOpcode(NewOpc)));
560 ImmOp.ChangeToImmediate(ImmedOffset);
561 Offset &= ~(Mask*Scale);
564 Offset = (isSub) ? -Offset : Offset;
568 /// scheduleTwoAddrSource - Schedule the copy / re-mat of the source of the
569 /// two-addrss instruction inserted by two-address pass.
571 Thumb2InstrInfo::scheduleTwoAddrSource(MachineInstr *SrcMI,
573 const TargetRegisterInfo &TRI) const {
574 if (SrcMI->getOpcode() != ARM::tMOVr || SrcMI->getOperand(1).isKill())
577 unsigned PredReg = 0;
578 ARMCC::CondCodes CC = llvm::getInstrPredicate(UseMI, PredReg);
579 if (CC == ARMCC::AL || PredReg != ARM::CPSR)
582 // Schedule the copy so it doesn't come between previous instructions
583 // and UseMI which can form an IT block.
584 unsigned SrcReg = SrcMI->getOperand(1).getReg();
585 ARMCC::CondCodes OCC = ARMCC::getOppositeCondition(CC);
586 MachineBasicBlock *MBB = UseMI->getParent();
587 MachineBasicBlock::iterator MBBI = SrcMI;
588 unsigned NumInsts = 0;
589 while (--MBBI != MBB->begin()) {
590 if (MBBI->isDebugValue())
593 MachineInstr *NMI = &*MBBI;
594 ARMCC::CondCodes NCC = llvm::getInstrPredicate(NMI, PredReg);
595 if (!(NCC == CC || NCC == OCC) ||
596 NMI->modifiesRegister(SrcReg, &TRI) ||
597 NMI->modifiesRegister(ARM::CPSR, &TRI))
600 // Too many in a row!
606 MBB->insert(++MBBI, SrcMI);
611 llvm::getITInstrPredicate(const MachineInstr *MI, unsigned &PredReg) {
612 unsigned Opc = MI->getOpcode();
613 if (Opc == ARM::tBcc || Opc == ARM::t2Bcc)
615 return llvm::getInstrPredicate(MI, PredReg);