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 "MCTargetDesc/ARMAddressingModes.h"
19 #include "llvm/CodeGen/MachineFrameInfo.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/CodeGen/MachineMemOperand.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/MC/MCInst.h"
24 #include "llvm/Support/CommandLine.h"
29 OldT2IfCvt("old-thumb2-ifcvt", cl::Hidden,
30 cl::desc("Use old-style Thumb2 if-conversion heuristics"),
33 Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI)
34 : ARMBaseInstrInfo(STI), RI(STI) {
37 /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
38 void Thumb2InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
39 NopInst.setOpcode(ARM::tNOP);
40 NopInst.addOperand(MCOperand::CreateImm(ARMCC::AL));
41 NopInst.addOperand(MCOperand::CreateReg(0));
44 unsigned Thumb2InstrInfo::getUnindexedOpcode(unsigned Opc) const {
50 Thumb2InstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
51 MachineBasicBlock *NewDest) const {
52 MachineBasicBlock *MBB = Tail->getParent();
53 ARMFunctionInfo *AFI = MBB->getParent()->getInfo<ARMFunctionInfo>();
54 if (!AFI->hasITBlocks()) {
55 TargetInstrInfo::ReplaceTailWithBranchTo(Tail, NewDest);
59 // If the first instruction of Tail is predicated, we may have to update
60 // the IT instruction.
62 ARMCC::CondCodes CC = getInstrPredicate(Tail, PredReg);
63 MachineBasicBlock::iterator MBBI = Tail;
65 // Expecting at least the t2IT instruction before it.
68 // Actually replace the tail.
69 TargetInstrInfo::ReplaceTailWithBranchTo(Tail, NewDest);
72 if (CC != ARMCC::AL) {
73 MachineBasicBlock::iterator E = MBB->begin();
74 unsigned Count = 4; // At most 4 instructions in an IT block.
75 while (Count && MBBI != E) {
76 if (MBBI->isDebugValue()) {
80 if (MBBI->getOpcode() == ARM::t2IT) {
81 unsigned Mask = MBBI->getOperand(1).getImm();
83 MBBI->eraseFromParent();
85 unsigned MaskOn = 1 << Count;
86 unsigned MaskOff = ~(MaskOn - 1);
87 MBBI->getOperand(1).setImm((Mask & MaskOff) | MaskOn);
95 // Ctrl flow can reach here if branch folding is run before IT block
101 Thumb2InstrInfo::isLegalToSplitMBBAt(MachineBasicBlock &MBB,
102 MachineBasicBlock::iterator MBBI) const {
103 while (MBBI->isDebugValue()) {
105 if (MBBI == MBB.end())
109 unsigned PredReg = 0;
110 return getITInstrPredicate(MBBI, PredReg) == ARMCC::AL;
113 void Thumb2InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
114 MachineBasicBlock::iterator I, DebugLoc DL,
115 unsigned DestReg, unsigned SrcReg,
116 bool KillSrc) const {
117 // Handle SPR, DPR, and QPR copies.
118 if (!ARM::GPRRegClass.contains(DestReg, SrcReg))
119 return ARMBaseInstrInfo::copyPhysReg(MBB, I, DL, DestReg, SrcReg, KillSrc);
121 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::tMOVr), DestReg)
122 .addReg(SrcReg, getKillRegState(KillSrc)));
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 =
136 MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
137 MachineMemOperand::MOStore,
138 MFI.getObjectSize(FI),
139 MFI.getObjectAlignment(FI));
141 if (RC == &ARM::GPRRegClass || RC == &ARM::tGPRRegClass ||
142 RC == &ARM::tcGPRRegClass || RC == &ARM::rGPRRegClass ||
143 RC == &ARM::GPRnopcRegClass) {
144 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2STRi12))
145 .addReg(SrcReg, getKillRegState(isKill))
146 .addFrameIndex(FI).addImm(0).addMemOperand(MMO));
150 if (ARM::GPRPairRegClass.hasSubClassEq(RC)) {
151 // Thumb2 STRD expects its dest-registers to be in rGPR. Not a problem for
152 // gsub_0, but needs an extra constraint for gsub_1 (which could be sp
154 MachineRegisterInfo *MRI = &MF.getRegInfo();
155 const TargetRegisterClass* TargetClass = TRI->getMatchingSuperRegClass(RC,
158 assert(TargetClass && "No Matching GPRPair with gsub_1 in rGPRRegClass");
159 const TargetRegisterClass* ConstrainedClass =
160 MRI->constrainRegClass(SrcReg, TargetClass);
161 assert(ConstrainedClass && "Couldn't constrain the register class");
163 MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(ARM::t2STRDi8));
164 AddDReg(MIB, SrcReg, ARM::gsub_0, getKillRegState(isKill), TRI);
165 AddDReg(MIB, SrcReg, ARM::gsub_1, 0, TRI);
166 MIB.addFrameIndex(FI).addImm(0).addMemOperand(MMO);
171 ARMBaseInstrInfo::storeRegToStackSlot(MBB, I, SrcReg, isKill, FI, RC, TRI);
174 void Thumb2InstrInfo::
175 loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
176 unsigned DestReg, int FI,
177 const TargetRegisterClass *RC,
178 const TargetRegisterInfo *TRI) const {
179 MachineFunction &MF = *MBB.getParent();
180 MachineFrameInfo &MFI = *MF.getFrameInfo();
181 MachineMemOperand *MMO =
182 MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
183 MachineMemOperand::MOLoad,
184 MFI.getObjectSize(FI),
185 MFI.getObjectAlignment(FI));
187 if (I != MBB.end()) DL = I->getDebugLoc();
189 if (RC == &ARM::GPRRegClass || RC == &ARM::tGPRRegClass ||
190 RC == &ARM::tcGPRRegClass || RC == &ARM::rGPRRegClass ||
191 RC == &ARM::GPRnopcRegClass) {
192 AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2LDRi12), DestReg)
193 .addFrameIndex(FI).addImm(0).addMemOperand(MMO));
197 if (ARM::GPRPairRegClass.hasSubClassEq(RC)) {
198 // Thumb2 LDRD expects its dest-registers to be in rGPR. Not a problem for
199 // gsub_0, but needs an extra constraint for gsub_1 (which could be sp
201 MachineRegisterInfo *MRI = &MF.getRegInfo();
202 const TargetRegisterClass* TargetClass = TRI->getMatchingSuperRegClass(RC,
205 assert(TargetClass && "No Matching GPRPair with gsub_1 in rGPRRegClass");
206 const TargetRegisterClass* ConstrainedClass =
207 MRI->constrainRegClass(DestReg, TargetClass);
208 assert(ConstrainedClass && "Couldn't constrain the register class");
210 MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(ARM::t2LDRDi8));
211 AddDReg(MIB, DestReg, ARM::gsub_0, RegState::DefineNoRead, TRI);
212 AddDReg(MIB, DestReg, ARM::gsub_1, RegState::DefineNoRead, TRI);
213 MIB.addFrameIndex(FI).addImm(0).addMemOperand(MMO);
216 if (TargetRegisterInfo::isPhysicalRegister(DestReg))
217 MIB.addReg(DestReg, RegState::ImplicitDefine);
221 ARMBaseInstrInfo::loadRegFromStackSlot(MBB, I, DestReg, FI, RC, TRI);
224 void llvm::emitT2RegPlusImmediate(MachineBasicBlock &MBB,
225 MachineBasicBlock::iterator &MBBI, DebugLoc dl,
226 unsigned DestReg, unsigned BaseReg, int NumBytes,
227 ARMCC::CondCodes Pred, unsigned PredReg,
228 const ARMBaseInstrInfo &TII, unsigned MIFlags) {
229 bool isSub = NumBytes < 0;
230 if (isSub) NumBytes = -NumBytes;
232 // If profitable, use a movw or movt to materialize the offset.
233 // FIXME: Use the scavenger to grab a scratch register.
234 if (DestReg != ARM::SP && DestReg != BaseReg &&
236 ARM_AM::getT2SOImmVal(NumBytes) == -1) {
238 if (NumBytes < 65536) {
239 // Use a movw to materialize the 16-bit constant.
240 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), DestReg)
242 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
244 } else if ((NumBytes & 0xffff) == 0) {
245 // Use a movt to materialize the 32-bit constant.
246 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVTi16), DestReg)
248 .addImm(NumBytes >> 16)
249 .addImm((unsigned)Pred).addReg(PredReg).setMIFlags(MIFlags);
255 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), DestReg)
256 .addReg(BaseReg, RegState::Kill)
257 .addReg(DestReg, RegState::Kill)
258 .addImm((unsigned)Pred).addReg(PredReg).addReg(0)
259 .setMIFlags(MIFlags);
261 BuildMI(MBB, MBBI, dl, TII.get(ARM::t2ADDrr), DestReg)
262 .addReg(DestReg, RegState::Kill)
263 .addReg(BaseReg, RegState::Kill)
264 .addImm((unsigned)Pred).addReg(PredReg).addReg(0)
265 .setMIFlags(MIFlags);
272 unsigned ThisVal = NumBytes;
274 if (DestReg == ARM::SP && BaseReg != ARM::SP) {
275 // mov sp, rn. Note t2MOVr cannot be used.
276 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr),DestReg)
277 .addReg(BaseReg).setMIFlags(MIFlags));
282 bool HasCCOut = true;
283 if (BaseReg == ARM::SP) {
285 if (DestReg == ARM::SP && (ThisVal < ((1 << 7)-1) * 4)) {
286 assert((ThisVal & 3) == 0 && "Stack update is not multiple of 4?");
287 Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
288 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
289 .addReg(BaseReg).addImm(ThisVal/4).setMIFlags(MIFlags));
294 // sub rd, sp, so_imm
295 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
296 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
299 // FIXME: Move this to ARMAddressingModes.h?
300 unsigned RotAmt = countLeadingZeros(ThisVal);
301 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
302 NumBytes &= ~ThisVal;
303 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
304 "Bit extraction didn't work?");
307 assert(DestReg != ARM::SP && BaseReg != ARM::SP);
308 Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
309 if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
311 } else if (ThisVal < 4096) {
312 Opc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
316 // FIXME: Move this to ARMAddressingModes.h?
317 unsigned RotAmt = countLeadingZeros(ThisVal);
318 ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
319 NumBytes &= ~ThisVal;
320 assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
321 "Bit extraction didn't work?");
325 // Build the new ADD / SUB.
326 MachineInstrBuilder MIB =
327 AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
328 .addReg(BaseReg, RegState::Kill)
329 .addImm(ThisVal)).setMIFlags(MIFlags);
338 negativeOffsetOpcode(unsigned opcode)
341 case ARM::t2LDRi12: return ARM::t2LDRi8;
342 case ARM::t2LDRHi12: return ARM::t2LDRHi8;
343 case ARM::t2LDRBi12: return ARM::t2LDRBi8;
344 case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
345 case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
346 case ARM::t2STRi12: return ARM::t2STRi8;
347 case ARM::t2STRBi12: return ARM::t2STRBi8;
348 case ARM::t2STRHi12: return ARM::t2STRHi8;
368 positiveOffsetOpcode(unsigned opcode)
371 case ARM::t2LDRi8: return ARM::t2LDRi12;
372 case ARM::t2LDRHi8: return ARM::t2LDRHi12;
373 case ARM::t2LDRBi8: return ARM::t2LDRBi12;
374 case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
375 case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
376 case ARM::t2STRi8: return ARM::t2STRi12;
377 case ARM::t2STRBi8: return ARM::t2STRBi12;
378 case ARM::t2STRHi8: return ARM::t2STRHi12;
383 case ARM::t2LDRSHi12:
384 case ARM::t2LDRSBi12:
398 immediateOffsetOpcode(unsigned opcode)
401 case ARM::t2LDRs: return ARM::t2LDRi12;
402 case ARM::t2LDRHs: return ARM::t2LDRHi12;
403 case ARM::t2LDRBs: return ARM::t2LDRBi12;
404 case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
405 case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
406 case ARM::t2STRs: return ARM::t2STRi12;
407 case ARM::t2STRBs: return ARM::t2STRBi12;
408 case ARM::t2STRHs: return ARM::t2STRHi12;
413 case ARM::t2LDRSHi12:
414 case ARM::t2LDRSBi12:
435 bool llvm::rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
436 unsigned FrameReg, int &Offset,
437 const ARMBaseInstrInfo &TII) {
438 unsigned Opcode = MI.getOpcode();
439 const MCInstrDesc &Desc = MI.getDesc();
440 unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
443 // Memory operands in inline assembly always use AddrModeT2_i12.
444 if (Opcode == ARM::INLINEASM)
445 AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
447 if (Opcode == ARM::t2ADDri || Opcode == ARM::t2ADDri12) {
448 Offset += MI.getOperand(FrameRegIdx+1).getImm();
451 if (Offset == 0 && getInstrPredicate(&MI, PredReg) == ARMCC::AL) {
452 // Turn it into a move.
453 MI.setDesc(TII.get(ARM::tMOVr));
454 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
455 // Remove offset and remaining explicit predicate operands.
456 do MI.RemoveOperand(FrameRegIdx+1);
457 while (MI.getNumOperands() > FrameRegIdx+1);
458 MachineInstrBuilder MIB(*MI.getParent()->getParent(), &MI);
463 bool HasCCOut = Opcode != ARM::t2ADDri12;
468 MI.setDesc(TII.get(ARM::t2SUBri));
470 MI.setDesc(TII.get(ARM::t2ADDri));
473 // Common case: small offset, fits into instruction.
474 if (ARM_AM::getT2SOImmVal(Offset) != -1) {
475 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
476 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
477 // Add cc_out operand if the original instruction did not have one.
479 MI.addOperand(MachineOperand::CreateReg(0, false));
483 // Another common case: imm12.
485 (!HasCCOut || MI.getOperand(MI.getNumOperands()-1).getReg() == 0)) {
486 unsigned NewOpc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
487 MI.setDesc(TII.get(NewOpc));
488 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
489 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
490 // Remove the cc_out operand.
492 MI.RemoveOperand(MI.getNumOperands()-1);
497 // Otherwise, extract 8 adjacent bits from the immediate into this
499 unsigned RotAmt = countLeadingZeros<unsigned>(Offset);
500 unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
502 // We will handle these bits from offset, clear them.
503 Offset &= ~ThisImmVal;
505 assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
506 "Bit extraction didn't work?");
507 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
508 // Add cc_out operand if the original instruction did not have one.
510 MI.addOperand(MachineOperand::CreateReg(0, false));
514 // AddrMode4 and AddrMode6 cannot handle any offset.
515 if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
518 // AddrModeT2_so cannot handle any offset. If there is no offset
519 // register then we change to an immediate version.
520 unsigned NewOpc = Opcode;
521 if (AddrMode == ARMII::AddrModeT2_so) {
522 unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
523 if (OffsetReg != 0) {
524 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
528 MI.RemoveOperand(FrameRegIdx+1);
529 MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
530 NewOpc = immediateOffsetOpcode(Opcode);
531 AddrMode = ARMII::AddrModeT2_i12;
534 unsigned NumBits = 0;
536 if (AddrMode == ARMII::AddrModeT2_i8 || AddrMode == ARMII::AddrModeT2_i12) {
537 // i8 supports only negative, and i12 supports only positive, so
538 // based on Offset sign convert Opcode to the appropriate
540 Offset += MI.getOperand(FrameRegIdx+1).getImm();
542 NewOpc = negativeOffsetOpcode(Opcode);
547 NewOpc = positiveOffsetOpcode(Opcode);
550 } else if (AddrMode == ARMII::AddrMode5) {
552 const MachineOperand &OffOp = MI.getOperand(FrameRegIdx+1);
553 int InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
554 if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
558 Offset += InstrOffs * 4;
559 assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
564 } else if (AddrMode == ARMII::AddrModeT2_i8s4) {
565 Offset += MI.getOperand(FrameRegIdx + 1).getImm() * 4;
567 // MCInst operand has already scaled value.
574 llvm_unreachable("Unsupported addressing mode!");
577 if (NewOpc != Opcode)
578 MI.setDesc(TII.get(NewOpc));
580 MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
582 // Attempt to fold address computation
583 // Common case: small offset, fits into instruction.
584 int ImmedOffset = Offset / Scale;
585 unsigned Mask = (1 << NumBits) - 1;
586 if ((unsigned)Offset <= Mask * Scale) {
587 // Replace the FrameIndex with fp/sp
588 MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
590 if (AddrMode == ARMII::AddrMode5)
591 // FIXME: Not consistent.
592 ImmedOffset |= 1 << NumBits;
594 ImmedOffset = -ImmedOffset;
596 ImmOp.ChangeToImmediate(ImmedOffset);
601 // Otherwise, offset doesn't fit. Pull in what we can to simplify
602 ImmedOffset = ImmedOffset & Mask;
604 if (AddrMode == ARMII::AddrMode5)
605 // FIXME: Not consistent.
606 ImmedOffset |= 1 << NumBits;
608 ImmedOffset = -ImmedOffset;
609 if (ImmedOffset == 0)
610 // Change the opcode back if the encoded offset is zero.
611 MI.setDesc(TII.get(positiveOffsetOpcode(NewOpc)));
614 ImmOp.ChangeToImmediate(ImmedOffset);
615 Offset &= ~(Mask*Scale);
618 Offset = (isSub) ? -Offset : Offset;
623 llvm::getITInstrPredicate(const MachineInstr *MI, unsigned &PredReg) {
624 unsigned Opc = MI->getOpcode();
625 if (Opc == ARM::tBcc || Opc == ARM::t2Bcc)
627 return getInstrPredicate(MI, PredReg);