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"
15 #include "ARMConstantPoolValue.h"
16 #include "ARMMachineFunctionInfo.h"
17 #include "MCTargetDesc/ARMAddressingModes.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/CodeGen/MachineInstrBuilder.h"
20 #include "llvm/CodeGen/MachineMemOperand.h"
21 #include "llvm/CodeGen/MachineRegisterInfo.h"
22 #include "llvm/MC/MCInst.h"
23 #include "llvm/Support/CommandLine.h"
28 OldT2IfCvt("old-thumb2-ifcvt", cl::Hidden,
29 cl::desc("Use old-style Thumb2 if-conversion heuristics"),
32 Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI)
33 : ARMBaseInstrInfo(STI), RI() {}
35 /// Return the noop instruction to use for a noop.
36 void Thumb2InstrInfo::getNoop(MCInst &NopInst) const {
37 NopInst.setOpcode(ARM::tHINT);
38 NopInst.addOperand(MCOperand::createImm(0));
39 NopInst.addOperand(MCOperand::createImm(ARMCC::AL));
40 NopInst.addOperand(MCOperand::createReg(0));
43 unsigned Thumb2InstrInfo::getUnindexedOpcode(unsigned Opc) const {
49 Thumb2InstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
50 MachineBasicBlock *NewDest) const {
51 MachineBasicBlock *MBB = Tail->getParent();
52 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
53 if (!AFI->hasITBlocks() || Tail->isBranch()) {
54 TargetInstrInfo::ReplaceTailWithBranchTo(Tail, NewDest);
58 // If the first instruction of Tail is predicated, we may have to update
59 // the IT instruction.
61 ARMCC::CondCodes CC = getInstrPredicate(*Tail, PredReg);
62 MachineBasicBlock::iterator MBBI = Tail;
64 // Expecting at least the t2IT instruction before it.
67 // Actually replace the tail.
68 TargetInstrInfo::ReplaceTailWithBranchTo(Tail, NewDest);
71 if (CC != ARMCC::AL) {
72 MachineBasicBlock::iterator E = MBB->begin();
73 unsigned Count = 4; // At most 4 instructions in an IT block.
74 while (Count && MBBI != E) {
75 if (MBBI->isDebugValue()) {
79 if (MBBI->getOpcode() == ARM::t2IT) {
80 unsigned Mask = MBBI->getOperand(1).getImm();
82 MBBI->eraseFromParent();
84 unsigned MaskOn = 1 << Count;
85 unsigned MaskOff = ~(MaskOn - 1);
86 MBBI->getOperand(1).setImm((Mask & MaskOff) | MaskOn);
94 // Ctrl flow can reach here if branch folding is run before IT block
100 Thumb2InstrInfo::isLegalToSplitMBBAt(MachineBasicBlock &MBB,
101 MachineBasicBlock::iterator MBBI) const {
102 while (MBBI->isDebugValue()) {
104 if (MBBI == MBB.end())
108 unsigned PredReg = 0;
109 return getITInstrPredicate(*MBBI, PredReg) == ARMCC::AL;
112 void Thumb2InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
113 MachineBasicBlock::iterator I,
114 const DebugLoc &DL, unsigned DestReg,
115 unsigned SrcReg, bool KillSrc) const {
116 // Handle SPR, DPR, and QPR copies.
117 if (!ARM::GPRRegClass.contains(DestReg, SrcReg))
118 return ARMBaseInstrInfo::copyPhysReg(MBB, I, DL, DestReg, SrcReg, KillSrc);
120 BuildMI(MBB, I, DL, get(ARM::tMOVr), DestReg)
121 .addReg(SrcReg, getKillRegState(KillSrc))
122 .add(predOps(ARMCC::AL));
125 void Thumb2InstrInfo::
126 storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
127 unsigned SrcReg, bool isKill, int FI,
128 const TargetRegisterClass *RC,
129 const TargetRegisterInfo *TRI) const {
131 if (I != MBB.end()) DL = I->getDebugLoc();
133 MachineFunction &MF = *MBB.getParent();
134 MachineFrameInfo &MFI = MF.getFrameInfo();
135 MachineMemOperand *MMO = MF.getMachineMemOperand(
136 MachinePointerInfo::getFixedStack(MF, FI), MachineMemOperand::MOStore,
137 MFI.getObjectSize(FI), MFI.getObjectAlignment(FI));
139 if (RC == &ARM::GPRRegClass || RC == &ARM::tGPRRegClass ||
140 RC == &ARM::tcGPRRegClass || RC == &ARM::rGPRRegClass ||
141 RC == &ARM::GPRnopcRegClass) {
142 BuildMI(MBB, I, DL, get(ARM::t2STRi12))
143 .addReg(SrcReg, getKillRegState(isKill))
147 .add(predOps(ARMCC::AL));
151 if (ARM::GPRPairRegClass.hasSubClassEq(RC)) {
152 // Thumb2 STRD expects its dest-registers to be in rGPR. Not a problem for
153 // gsub_0, but needs an extra constraint for gsub_1 (which could be sp
155 if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
156 MachineRegisterInfo *MRI = &MF.getRegInfo();
157 MRI->constrainRegClass(SrcReg, &ARM::GPRPair_with_gsub_1_in_rGPRRegClass);
160 MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(ARM::t2STRDi8));
161 AddDReg(MIB, SrcReg, ARM::gsub_0, getKillRegState(isKill), TRI);
162 AddDReg(MIB, SrcReg, ARM::gsub_1, 0, TRI);
163 MIB.addFrameIndex(FI).addImm(0).addMemOperand(MMO).add(predOps(ARMCC::AL));
167 ARMBaseInstrInfo::storeRegToStackSlot(MBB, I, SrcReg, isKill, FI, RC, TRI);
170 void Thumb2InstrInfo::
171 loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
172 unsigned DestReg, int FI,
173 const TargetRegisterClass *RC,
174 const TargetRegisterInfo *TRI) const {
175 MachineFunction &MF = *MBB.getParent();
176 MachineFrameInfo &MFI = MF.getFrameInfo();
177 MachineMemOperand *MMO = MF.getMachineMemOperand(
178 MachinePointerInfo::getFixedStack(MF, FI), MachineMemOperand::MOLoad,
179 MFI.getObjectSize(FI), MFI.getObjectAlignment(FI));
181 if (I != MBB.end()) DL = I->getDebugLoc();
183 if (RC == &ARM::GPRRegClass || RC == &ARM::tGPRRegClass ||
184 RC == &ARM::tcGPRRegClass || RC == &ARM::rGPRRegClass ||
185 RC == &ARM::GPRnopcRegClass) {
186 BuildMI(MBB, I, DL, get(ARM::t2LDRi12), DestReg)
190 .add(predOps(ARMCC::AL));
194 if (ARM::GPRPairRegClass.hasSubClassEq(RC)) {
195 // Thumb2 LDRD expects its dest-registers to be in rGPR. Not a problem for
196 // gsub_0, but needs an extra constraint for gsub_1 (which could be sp
198 if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
199 MachineRegisterInfo *MRI = &MF.getRegInfo();
200 MRI->constrainRegClass(DestReg,
201 &ARM::GPRPair_with_gsub_1_in_rGPRRegClass);
204 MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(ARM::t2LDRDi8));
205 AddDReg(MIB, DestReg, ARM::gsub_0, RegState::DefineNoRead, TRI);
206 AddDReg(MIB, DestReg, ARM::gsub_1, RegState::DefineNoRead, TRI);
207 MIB.addFrameIndex(FI).addImm(0).addMemOperand(MMO).add(predOps(ARMCC::AL));
209 if (TargetRegisterInfo::isPhysicalRegister(DestReg))
210 MIB.addReg(DestReg, RegState::ImplicitDefine);
214 ARMBaseInstrInfo::loadRegFromStackSlot(MBB, I, DestReg, FI, RC, TRI);
217 void Thumb2InstrInfo::expandLoadStackGuard(
218 MachineBasicBlock::iterator MI) const {
219 MachineFunction &MF = *MI->getParent()->getParent();
220 if (MF.getTarget().isPositionIndependent())
221 expandLoadStackGuardBase(MI, ARM::t2MOV_ga_pcrel, ARM::t2LDRi12);
223 expandLoadStackGuardBase(MI, ARM::t2MOVi32imm, ARM::t2LDRi12);
226 void llvm::emitT2RegPlusImmediate(MachineBasicBlock &MBB,
227 MachineBasicBlock::iterator &MBBI,
228 const DebugLoc &dl, unsigned DestReg,
229 unsigned BaseReg, int NumBytes,
230 ARMCC::CondCodes Pred, unsigned PredReg,
231 const ARMBaseInstrInfo &TII,
233 if (NumBytes == 0 && DestReg != BaseReg) {
234 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
235 .addReg(BaseReg, RegState::Kill)
236 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
240 bool isSub = NumBytes < 0;
241 if (isSub) NumBytes = -NumBytes;
243 // If profitable, use a movw or movt to materialize the offset.
244 // FIXME: Use the scavenger to grab a scratch register.
245 if (DestReg != ARM::SP && DestReg != BaseReg &&
247 ARM_AM::getT2SOImmVal(NumBytes) == -1) {
249 if (NumBytes < 65536) {
250 // Use a movw to materialize the 16-bit constant.
251 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), DestReg)
253 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
255 } else if ((NumBytes & 0xffff) == 0) {
256 // Use a movt to materialize the 32-bit constant.
257 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVTi16), DestReg)
259 .addImm(NumBytes >> 16)
260 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
266 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), DestReg)
268 .addReg(DestReg, RegState::Kill)
269 .add(predOps(Pred, PredReg))
271 .setMIFlags(MIFlags);
273 // Here we know that DestReg is not SP but we do not
274 // know anything about BaseReg. t2ADDrr is an invalid
275 // instruction is SP is used as the second argument, but
276 // is fine if SP is the first argument. To be sure we
277 // do not generate invalid encoding, put BaseReg first.
278 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2ADDrr), DestReg)
280 .addReg(DestReg, RegState::Kill)
281 .add(predOps(Pred, PredReg))
283 .setMIFlags(MIFlags);
290 unsigned ThisVal = NumBytes;
292 if (DestReg == ARM::SP && BaseReg != ARM::SP) {
293 // mov sp, rn. Note t2MOVr cannot be used.
294 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
297 .add(predOps(ARMCC::AL));
302 bool HasCCOut = true;
303 if (BaseReg == ARM::SP) {
305 if (DestReg == ARM::SP && (ThisVal < ((1 << 7)-1) * 4)) {
306 assert((ThisVal & 3) == 0 && "Stack update is not multiple of 4?");
307 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
308 BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
312 .add(predOps(ARMCC::AL));
317 // sub rd, sp, so_imm
318 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
319 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
322 // FIXME: Move this to ARMAddressingModes.h?
323 unsigned RotAmt = countLeadingZeros(ThisVal);
324 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
325 NumBytes &= ~ThisVal;
326 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
327 "Bit extraction didn't work?");
330 assert(DestReg != ARM::SP && BaseReg != ARM::SP);
331 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
332 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
334 } else if (ThisVal < 4096) {
335 Opc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
339 // FIXME: Move this to ARMAddressingModes.h?
340 unsigned RotAmt = countLeadingZeros(ThisVal);
341 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
342 NumBytes &= ~ThisVal;
343 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
344 "Bit extraction didn't work?");
348 // Build the new ADD / SUB.
349 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
350 .addReg(BaseReg, RegState::Kill)
352 .add(predOps(ARMCC::AL))
353 .setMIFlags(MIFlags);
355 MIB.add(condCodeOp());
362 negativeOffsetOpcode(unsigned opcode)
365 case ARM::t2LDRi12: return ARM::t2LDRi8;
366 case ARM::t2LDRHi12: return ARM::t2LDRHi8;
367 case ARM::t2LDRBi12: return ARM::t2LDRBi8;
368 case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
369 case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
370 case ARM::t2STRi12: return ARM::t2STRi8;
371 case ARM::t2STRBi12: return ARM::t2STRBi8;
372 case ARM::t2STRHi12: return ARM::t2STRHi8;
373 case ARM::t2PLDi12: return ARM::t2PLDi8;
394 positiveOffsetOpcode(unsigned opcode)
397 case ARM::t2LDRi8: return ARM::t2LDRi12;
398 case ARM::t2LDRHi8: return ARM::t2LDRHi12;
399 case ARM::t2LDRBi8: return ARM::t2LDRBi12;
400 case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
401 case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
402 case ARM::t2STRi8: return ARM::t2STRi12;
403 case ARM::t2STRBi8: return ARM::t2STRBi12;
404 case ARM::t2STRHi8: return ARM::t2STRHi12;
405 case ARM::t2PLDi8: return ARM::t2PLDi12;
410 case ARM::t2LDRSHi12:
411 case ARM::t2LDRSBi12:
426 immediateOffsetOpcode(unsigned opcode)
429 case ARM::t2LDRs: return ARM::t2LDRi12;
430 case ARM::t2LDRHs: return ARM::t2LDRHi12;
431 case ARM::t2LDRBs: return ARM::t2LDRBi12;
432 case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
433 case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
434 case ARM::t2STRs: return ARM::t2STRi12;
435 case ARM::t2STRBs: return ARM::t2STRBi12;
436 case ARM::t2STRHs: return ARM::t2STRHi12;
437 case ARM::t2PLDs: return ARM::t2PLDi12;
442 case ARM::t2LDRSHi12:
443 case ARM::t2LDRSBi12:
466 bool llvm::rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
467 unsigned FrameReg, int &Offset,
468 const ARMBaseInstrInfo &TII) {
469 unsigned Opcode = MI.getOpcode();
470 const MCInstrDesc &Desc = MI.getDesc();
471 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
474 // Memory operands in inline assembly always use AddrModeT2_i12.
475 if (Opcode == ARM::INLINEASM)
476 AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
478 if (Opcode == ARM::t2ADDri || Opcode == ARM::t2ADDri12) {
479 Offset += MI.getOperand(FrameRegIdx+1).getImm();
482 if (Offset == 0 && getInstrPredicate(MI, PredReg) == ARMCC::AL) {
483 // Turn it into a move.
484 MI.setDesc(TII.get(ARM::tMOVr));
485 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
486 // Remove offset and remaining explicit predicate operands.
487 do MI.RemoveOperand(FrameRegIdx+1);
488 while (MI.getNumOperands() > FrameRegIdx+1);
489 MachineInstrBuilder MIB(*MI.getParent()->getParent(), &MI);
490 MIB.add(predOps(ARMCC::AL));
494 bool HasCCOut = Opcode != ARM::t2ADDri12;
499 MI.setDesc(TII.get(ARM::t2SUBri));
501 MI.setDesc(TII.get(ARM::t2ADDri));
504 // Common case: small offset, fits into instruction.
505 if (ARM_AM::getT2SOImmVal(Offset) != -1) {
506 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
507 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
508 // Add cc_out operand if the original instruction did not have one.
510 MI.addOperand(MachineOperand::CreateReg(0, false));
514 // Another common case: imm12.
516 (!HasCCOut || MI.getOperand(MI.getNumOperands()-1).getReg() == 0)) {
517 unsigned NewOpc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
518 MI.setDesc(TII.get(NewOpc));
519 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
520 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
521 // Remove the cc_out operand.
523 MI.RemoveOperand(MI.getNumOperands()-1);
528 // Otherwise, extract 8 adjacent bits from the immediate into this
530 unsigned RotAmt = countLeadingZeros<unsigned>(Offset);
531 unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
533 // We will handle these bits from offset, clear them.
534 Offset &= ~ThisImmVal;
536 assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
537 "Bit extraction didn't work?");
538 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
539 // Add cc_out operand if the original instruction did not have one.
541 MI.addOperand(MachineOperand::CreateReg(0, false));
545 // AddrMode4 and AddrMode6 cannot handle any offset.
546 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
549 // AddrModeT2_so cannot handle any offset. If there is no offset
550 // register then we change to an immediate version.
551 unsigned NewOpc = Opcode;
552 if (AddrMode == ARMII::AddrModeT2_so) {
553 unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
554 if (OffsetReg != 0) {
555 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
559 MI.RemoveOperand(FrameRegIdx+1);
560 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
561 NewOpc = immediateOffsetOpcode(Opcode);
562 AddrMode = ARMII::AddrModeT2_i12;
565 unsigned NumBits = 0;
567 if (AddrMode == ARMII::AddrModeT2_i8 || AddrMode == ARMII::AddrModeT2_i12) {
568 // i8 supports only negative, and i12 supports only positive, so
569 // based on Offset sign convert Opcode to the appropriate
571 Offset += MI.getOperand(FrameRegIdx+1).getImm();
573 NewOpc = negativeOffsetOpcode(Opcode);
578 NewOpc = positiveOffsetOpcode(Opcode);
581 } else if (AddrMode == ARMII::AddrMode5) {
583 const MachineOperand &OffOp = MI.getOperand(FrameRegIdx+1);
584 int InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
585 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
589 Offset += InstrOffs * 4;
590 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
595 } else if (AddrMode == ARMII::AddrModeT2_i8s4) {
596 Offset += MI.getOperand(FrameRegIdx + 1).getImm() * 4;
597 NumBits = 10; // 8 bits scaled by 4
598 // MCInst operand expects already scaled value.
600 assert((Offset & 3) == 0 && "Can't encode this offset!");
602 llvm_unreachable("Unsupported addressing mode!");
605 if (NewOpc != Opcode)
606 MI.setDesc(TII.get(NewOpc));
608 MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
610 // Attempt to fold address computation
611 // Common case: small offset, fits into instruction.
612 int ImmedOffset = Offset / Scale;
613 unsigned Mask = (1 << NumBits) - 1;
614 if ((unsigned)Offset <= Mask * Scale) {
615 // Replace the FrameIndex with fp/sp
616 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
618 if (AddrMode == ARMII::AddrMode5)
619 // FIXME: Not consistent.
620 ImmedOffset |= 1 << NumBits;
622 ImmedOffset = -ImmedOffset;
624 ImmOp.ChangeToImmediate(ImmedOffset);
629 // Otherwise, offset doesn't fit. Pull in what we can to simplify
630 ImmedOffset = ImmedOffset & Mask;
632 if (AddrMode == ARMII::AddrMode5)
633 // FIXME: Not consistent.
634 ImmedOffset |= 1 << NumBits;
636 ImmedOffset = -ImmedOffset;
637 if (ImmedOffset == 0)
638 // Change the opcode back if the encoded offset is zero.
639 MI.setDesc(TII.get(positiveOffsetOpcode(NewOpc)));
642 ImmOp.ChangeToImmediate(ImmedOffset);
643 Offset &= ~(Mask*Scale);
646 Offset = (isSub) ? -Offset : Offset;
650 ARMCC::CondCodes llvm::getITInstrPredicate(const MachineInstr &MI,
652 unsigned Opc = MI.getOpcode();
653 if (Opc == ARM::tBcc || Opc == ARM::t2Bcc)
655 return getInstrPredicate(MI, PredReg);