1 //===-- MipsInstrInfo.cpp - Mips 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 Mips implementation of the TargetInstrInfo class.
12 //===----------------------------------------------------------------------===//
14 #include "MipsInstrInfo.h"
15 #include "InstPrinter/MipsInstPrinter.h"
16 #include "MipsMachineFunction.h"
17 #include "MipsSubtarget.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/CodeGen/MachineInstrBuilder.h"
20 #include "llvm/CodeGen/MachineRegisterInfo.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/TargetRegistry.h"
26 #define GET_INSTRINFO_CTOR_DTOR
27 #include "MipsGenInstrInfo.inc"
29 // Pin the vtable to this file.
30 void MipsInstrInfo::anchor() {}
32 MipsInstrInfo::MipsInstrInfo(const MipsSubtarget &STI, unsigned UncondBr)
33 : MipsGenInstrInfo(Mips::ADJCALLSTACKDOWN, Mips::ADJCALLSTACKUP),
34 Subtarget(STI), UncondBrOpc(UncondBr) {}
36 const MipsInstrInfo *MipsInstrInfo::create(MipsSubtarget &STI) {
37 if (STI.inMips16Mode())
38 return llvm::createMips16InstrInfo(STI);
40 return llvm::createMipsSEInstrInfo(STI);
43 bool MipsInstrInfo::isZeroImm(const MachineOperand &op) const {
44 return op.isImm() && op.getImm() == 0;
47 /// insertNoop - If data hazard condition is found insert the target nop
49 // FIXME: This appears to be dead code.
51 insertNoop(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const
54 BuildMI(MBB, MI, DL, get(Mips::NOP));
58 MipsInstrInfo::GetMemOperand(MachineBasicBlock &MBB, int FI,
59 MachineMemOperand::Flags Flags) const {
60 MachineFunction &MF = *MBB.getParent();
61 MachineFrameInfo &MFI = MF.getFrameInfo();
62 unsigned Align = MFI.getObjectAlignment(FI);
64 return MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(MF, FI),
65 Flags, MFI.getObjectSize(FI), Align);
68 //===----------------------------------------------------------------------===//
70 //===----------------------------------------------------------------------===//
72 void MipsInstrInfo::AnalyzeCondBr(const MachineInstr *Inst, unsigned Opc,
73 MachineBasicBlock *&BB,
74 SmallVectorImpl<MachineOperand> &Cond) const {
75 assert(getAnalyzableBrOpc(Opc) && "Not an analyzable branch");
76 int NumOp = Inst->getNumExplicitOperands();
78 // for both int and fp branches, the last explicit operand is the
80 BB = Inst->getOperand(NumOp-1).getMBB();
81 Cond.push_back(MachineOperand::CreateImm(Opc));
83 for (int i=0; i<NumOp-1; i++)
84 Cond.push_back(Inst->getOperand(i));
87 bool MipsInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
88 MachineBasicBlock *&TBB,
89 MachineBasicBlock *&FBB,
90 SmallVectorImpl<MachineOperand> &Cond,
91 bool AllowModify) const {
92 SmallVector<MachineInstr*, 2> BranchInstrs;
93 BranchType BT = analyzeBranch(MBB, TBB, FBB, Cond, AllowModify, BranchInstrs);
95 return (BT == BT_None) || (BT == BT_Indirect);
98 void MipsInstrInfo::BuildCondBr(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
100 ArrayRef<MachineOperand> Cond) const {
101 unsigned Opc = Cond[0].getImm();
102 const MCInstrDesc &MCID = get(Opc);
103 MachineInstrBuilder MIB = BuildMI(&MBB, DL, MCID);
105 for (unsigned i = 1; i < Cond.size(); ++i) {
106 assert((Cond[i].isImm() || Cond[i].isReg()) &&
107 "Cannot copy operand for conditional branch!");
113 unsigned MipsInstrInfo::insertBranch(MachineBasicBlock &MBB,
114 MachineBasicBlock *TBB,
115 MachineBasicBlock *FBB,
116 ArrayRef<MachineOperand> Cond,
118 int *BytesAdded) const {
119 // Shouldn't be a fall through.
120 assert(TBB && "insertBranch must not be told to insert a fallthrough");
121 assert(!BytesAdded && "code size not handled");
123 // # of condition operands:
124 // Unconditional branches: 0
125 // Floating point branches: 1 (opc)
126 // Int BranchZero: 2 (opc, reg)
127 // Int Branch: 3 (opc, reg0, reg1)
128 assert((Cond.size() <= 3) &&
129 "# of Mips branch conditions must be <= 3!");
131 // Two-way Conditional branch.
133 BuildCondBr(MBB, TBB, DL, Cond);
134 BuildMI(&MBB, DL, get(UncondBrOpc)).addMBB(FBB);
139 // Unconditional branch.
141 BuildMI(&MBB, DL, get(UncondBrOpc)).addMBB(TBB);
142 else // Conditional branch.
143 BuildCondBr(MBB, TBB, DL, Cond);
147 unsigned MipsInstrInfo::removeBranch(MachineBasicBlock &MBB,
148 int *BytesRemoved) const {
149 assert(!BytesRemoved && "code size not handled");
151 MachineBasicBlock::reverse_iterator I = MBB.rbegin(), REnd = MBB.rend();
154 // Skip all the debug instructions.
155 while (I != REnd && I->isDebugValue())
161 MachineBasicBlock::iterator FirstBr = ++I.getReverse();
163 // Up to 2 branches are removed.
164 // Note that indirect branches are not removed.
165 for (removed = 0; I != REnd && removed < 2; ++I, ++removed)
166 if (!getAnalyzableBrOpc(I->getOpcode()))
169 MBB.erase((--I).getReverse(), FirstBr);
174 /// reverseBranchCondition - Return the inverse opcode of the
175 /// specified Branch instruction.
176 bool MipsInstrInfo::reverseBranchCondition(
177 SmallVectorImpl<MachineOperand> &Cond) const {
178 assert( (Cond.size() && Cond.size() <= 3) &&
179 "Invalid Mips branch condition!");
180 Cond[0].setImm(getOppositeBranchOpc(Cond[0].getImm()));
184 MipsInstrInfo::BranchType MipsInstrInfo::analyzeBranch(
185 MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB,
186 SmallVectorImpl<MachineOperand> &Cond, bool AllowModify,
187 SmallVectorImpl<MachineInstr *> &BranchInstrs) const {
189 MachineBasicBlock::reverse_iterator I = MBB.rbegin(), REnd = MBB.rend();
191 // Skip all the debug instructions.
192 while (I != REnd && I->isDebugValue())
195 if (I == REnd || !isUnpredicatedTerminator(*I)) {
196 // This block ends with no branches (it just falls through to its succ).
197 // Leave TBB/FBB null.
202 MachineInstr *LastInst = &*I;
203 unsigned LastOpc = LastInst->getOpcode();
204 BranchInstrs.push_back(LastInst);
206 // Not an analyzable branch (e.g., indirect jump).
207 if (!getAnalyzableBrOpc(LastOpc))
208 return LastInst->isIndirectBranch() ? BT_Indirect : BT_None;
210 // Get the second to last instruction in the block.
211 unsigned SecondLastOpc = 0;
212 MachineInstr *SecondLastInst = nullptr;
215 SecondLastInst = &*I;
216 SecondLastOpc = getAnalyzableBrOpc(SecondLastInst->getOpcode());
218 // Not an analyzable branch (must be an indirect jump).
219 if (isUnpredicatedTerminator(*SecondLastInst) && !SecondLastOpc)
223 // If there is only one terminator instruction, process it.
224 if (!SecondLastOpc) {
225 // Unconditional branch.
226 if (LastInst->isUnconditionalBranch()) {
227 TBB = LastInst->getOperand(0).getMBB();
231 // Conditional branch
232 AnalyzeCondBr(LastInst, LastOpc, TBB, Cond);
236 // If we reached here, there are two branches.
237 // If there are three terminators, we don't know what sort of block this is.
238 if (++I != REnd && isUnpredicatedTerminator(*I))
241 BranchInstrs.insert(BranchInstrs.begin(), SecondLastInst);
243 // If second to last instruction is an unconditional branch,
244 // analyze it and remove the last instruction.
245 if (SecondLastInst->isUnconditionalBranch()) {
246 // Return if the last instruction cannot be removed.
250 TBB = SecondLastInst->getOperand(0).getMBB();
251 LastInst->eraseFromParent();
252 BranchInstrs.pop_back();
256 // Conditional branch followed by an unconditional branch.
257 // The last one must be unconditional.
258 if (!LastInst->isUnconditionalBranch())
261 AnalyzeCondBr(SecondLastInst, SecondLastOpc, TBB, Cond);
262 FBB = LastInst->getOperand(0).getMBB();
264 return BT_CondUncond;
267 /// Return the corresponding compact (no delay slot) form of a branch.
268 unsigned MipsInstrInfo::getEquivalentCompactForm(
269 const MachineBasicBlock::iterator I) const {
270 unsigned Opcode = I->getOpcode();
271 bool canUseShortMicroMipsCTI = false;
273 if (Subtarget.inMicroMipsMode()) {
279 // microMIPS has NE,EQ branches that do not have delay slots provided one
280 // of the operands is zero.
281 if (I->getOperand(1).getReg() == Subtarget.getABI().GetZeroReg())
282 canUseShortMicroMipsCTI = true;
284 // For microMIPS the PseudoReturn and PseudoIndirectBranch are always
285 // expanded to JR_MM, so they can be replaced with JRC16_MM.
287 case Mips::PseudoReturn:
288 case Mips::PseudoIndirectBranch:
289 case Mips::TAILCALLREG:
290 canUseShortMicroMipsCTI = true;
295 // MIPSR6 forbids both operands being the zero register.
296 if (Subtarget.hasMips32r6() && (I->getNumOperands() > 1) &&
297 (I->getOperand(0).isReg() &&
298 (I->getOperand(0).getReg() == Mips::ZERO ||
299 I->getOperand(0).getReg() == Mips::ZERO_64)) &&
300 (I->getOperand(1).isReg() &&
301 (I->getOperand(1).getReg() == Mips::ZERO ||
302 I->getOperand(1).getReg() == Mips::ZERO_64)))
305 if (Subtarget.hasMips32r6() || canUseShortMicroMipsCTI) {
313 if (canUseShortMicroMipsCTI)
314 return Mips::BEQZC_MM;
315 else if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
320 if (canUseShortMicroMipsCTI)
321 return Mips::BNEZC_MM;
322 else if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
326 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
330 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
340 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
344 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
350 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
354 if (I->getOperand(0).getReg() == I->getOperand(1).getReg())
358 return Mips::BGTZC64;
360 return Mips::BGEZC64;
362 return Mips::BLTZC64;
364 return Mips::BLEZC64;
365 // For MIPSR6, the instruction 'jic' can be used for these cases. Some
366 // tools will accept 'jrc reg' as an alias for 'jic 0, $reg'.
368 case Mips::PseudoReturn:
369 case Mips::PseudoIndirectBranch:
370 case Mips::TAILCALLREG:
371 if (canUseShortMicroMipsCTI)
372 return Mips::JRC16_MM;
374 case Mips::JALRPseudo:
377 case Mips::PseudoReturn64:
378 case Mips::PseudoIndirectBranch64:
379 case Mips::TAILCALLREG64:
381 case Mips::JALR64Pseudo:
382 return Mips::JIALC64;
391 /// Predicate for distingushing between control transfer instructions and all
392 /// other instructions for handling forbidden slots. Consider inline assembly
393 /// as unsafe as well.
394 bool MipsInstrInfo::SafeInForbiddenSlot(const MachineInstr &MI) const {
395 if (MI.isInlineAsm())
398 return (MI.getDesc().TSFlags & MipsII::IsCTI) == 0;
402 /// Predicate for distingushing instructions that have forbidden slots.
403 bool MipsInstrInfo::HasForbiddenSlot(const MachineInstr &MI) const {
404 return (MI.getDesc().TSFlags & MipsII::HasForbiddenSlot) != 0;
407 /// Return the number of bytes of code the specified instruction may be.
408 unsigned MipsInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
409 switch (MI.getOpcode()) {
411 return MI.getDesc().getSize();
412 case TargetOpcode::INLINEASM: { // Inline Asm: Variable size.
413 const MachineFunction *MF = MI.getParent()->getParent();
414 const char *AsmStr = MI.getOperand(0).getSymbolName();
415 return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo());
417 case Mips::CONSTPOOL_ENTRY:
418 // If this machine instr is a constant pool entry, its size is recorded as
420 return MI.getOperand(2).getImm();
425 MipsInstrInfo::genInstrWithNewOpc(unsigned NewOpc,
426 MachineBasicBlock::iterator I) const {
427 MachineInstrBuilder MIB;
429 // Certain branches have two forms: e.g beq $1, $zero, dest vs beqz $1, dest
430 // Pick the zero form of the branch for readable assembly and for greater
431 // branch distance in non-microMIPS mode.
432 // Additional MIPSR6 does not permit the use of register $zero for compact
434 // FIXME: Certain atomic sequences on mips64 generate 32bit references to
435 // Mips::ZERO, which is incorrect. This test should be updated to use
436 // Subtarget.getABI().GetZeroReg() when those atomic sequences and others
438 int ZeroOperandPosition = -1;
439 bool BranchWithZeroOperand = false;
440 if (I->isBranch() && !I->isPseudo()) {
441 auto TRI = I->getParent()->getParent()->getSubtarget().getRegisterInfo();
442 ZeroOperandPosition = I->findRegisterUseOperandIdx(Mips::ZERO, false, TRI);
443 BranchWithZeroOperand = ZeroOperandPosition != -1;
446 if (BranchWithZeroOperand) {
449 NewOpc = Mips::BEQZC;
452 NewOpc = Mips::BNEZC;
455 NewOpc = Mips::BGEZC;
458 NewOpc = Mips::BLTZC;
461 NewOpc = Mips::BEQZC64;
464 NewOpc = Mips::BNEZC64;
469 MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), get(NewOpc));
471 // For MIPSR6 JI*C requires an immediate 0 as an operand, JIALC(64) an
472 // immediate 0 as an operand and requires the removal of it's %RA<imp-def>
473 // implicit operand as copying the implicit operations of the instructio we're
474 // looking at will give us the correct flags.
475 if (NewOpc == Mips::JIC || NewOpc == Mips::JIALC || NewOpc == Mips::JIC64 ||
476 NewOpc == Mips::JIALC64) {
478 if (NewOpc == Mips::JIALC || NewOpc == Mips::JIALC64)
479 MIB->RemoveOperand(0);
481 for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) {
482 MIB.add(I->getOperand(J));
488 for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) {
489 if (BranchWithZeroOperand && (unsigned)ZeroOperandPosition == J)
492 MIB.add(I->getOperand(J));
496 MIB.copyImplicitOps(*I);
498 MIB.setMemRefs(I->memoperands_begin(), I->memoperands_end());
502 bool MipsInstrInfo::findCommutedOpIndices(MachineInstr &MI, unsigned &SrcOpIdx1,
503 unsigned &SrcOpIdx2) const {
504 assert(!MI.isBundle() &&
505 "TargetInstrInfo::findCommutedOpIndices() can't handle bundles");
507 const MCInstrDesc &MCID = MI.getDesc();
508 if (!MCID.isCommutable())
511 switch (MI.getOpcode()) {
512 case Mips::DPADD_U_H:
513 case Mips::DPADD_U_W:
514 case Mips::DPADD_U_D:
515 case Mips::DPADD_S_H:
516 case Mips::DPADD_S_W:
517 case Mips::DPADD_S_D: {
518 // The first operand is both input and output, so it should not commute
519 if (!fixCommutedOpIndices(SrcOpIdx1, SrcOpIdx2, 2, 3))
522 if (!MI.getOperand(SrcOpIdx1).isReg() || !MI.getOperand(SrcOpIdx2).isReg())
527 return TargetInstrInfo::findCommutedOpIndices(MI, SrcOpIdx1, SrcOpIdx2);