1 //===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===//
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 describes the target machine instruction set to the code generator.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TARGET_TARGETINSTRINFO_H
15 #define LLVM_TARGET_TARGETINSTRINFO_H
17 #include "llvm/MC/MCInstrInfo.h"
18 #include "llvm/CodeGen/MachineFunction.h"
22 class InstrItineraryData;
25 class MachineMemOperand;
26 class MachineRegisterInfo;
30 class ScheduleHazardRecognizer;
33 class TargetRegisterClass;
34 class TargetRegisterInfo;
36 template<class T> class SmallVectorImpl;
39 //---------------------------------------------------------------------------
41 /// TargetInstrInfo - Interface to description of machine instruction set
43 class TargetInstrInfo : public MCInstrInfo {
44 TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT
45 void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT
47 TargetInstrInfo(int CFSetupOpcode = -1, int CFDestroyOpcode = -1)
48 : CallFrameSetupOpcode(CFSetupOpcode),
49 CallFrameDestroyOpcode(CFDestroyOpcode) {
52 virtual ~TargetInstrInfo();
54 /// getRegClass - Givem a machine instruction descriptor, returns the register
55 /// class constraint for OpNum, or NULL.
56 const TargetRegisterClass *getRegClass(const MCInstrDesc &TID,
58 const TargetRegisterInfo *TRI) const;
60 /// isTriviallyReMaterializable - Return true if the instruction is trivially
61 /// rematerializable, meaning it has no side effects and requires no operands
62 /// that aren't always available.
63 bool isTriviallyReMaterializable(const MachineInstr *MI,
64 AliasAnalysis *AA = 0) const {
65 return MI->getOpcode() == TargetOpcode::IMPLICIT_DEF ||
66 (MI->getDesc().isRematerializable() &&
67 (isReallyTriviallyReMaterializable(MI, AA) ||
68 isReallyTriviallyReMaterializableGeneric(MI, AA)));
72 /// isReallyTriviallyReMaterializable - For instructions with opcodes for
73 /// which the M_REMATERIALIZABLE flag is set, this hook lets the target
74 /// specify whether the instruction is actually trivially rematerializable,
75 /// taking into consideration its operands. This predicate must return false
76 /// if the instruction has any side effects other than producing a value, or
77 /// if it requres any address registers that are not always available.
78 virtual bool isReallyTriviallyReMaterializable(const MachineInstr *MI,
79 AliasAnalysis *AA) const {
84 /// isReallyTriviallyReMaterializableGeneric - For instructions with opcodes
85 /// for which the M_REMATERIALIZABLE flag is set and the target hook
86 /// isReallyTriviallyReMaterializable returns false, this function does
87 /// target-independent tests to determine if the instruction is really
88 /// trivially rematerializable.
89 bool isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI,
90 AliasAnalysis *AA) const;
93 /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the
94 /// frame setup/destroy instructions if they exist (-1 otherwise). Some
95 /// targets use pseudo instructions in order to abstract away the difference
96 /// between operating with a frame pointer and operating without, through the
97 /// use of these two instructions.
99 int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; }
100 int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; }
102 /// isCoalescableExtInstr - Return true if the instruction is a "coalescable"
103 /// extension instruction. That is, it's like a copy where it's legal for the
104 /// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns
105 /// true, then it's expected the pre-extension value is available as a subreg
106 /// of the result register. This also returns the sub-register index in
108 virtual bool isCoalescableExtInstr(const MachineInstr &MI,
109 unsigned &SrcReg, unsigned &DstReg,
110 unsigned &SubIdx) const {
114 /// isLoadFromStackSlot - If the specified machine instruction is a direct
115 /// load from a stack slot, return the virtual or physical register number of
116 /// the destination along with the FrameIndex of the loaded stack slot. If
117 /// not, return 0. This predicate must return 0 if the instruction has
118 /// any side effects other than loading from the stack slot.
119 virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
120 int &FrameIndex) const {
124 /// isLoadFromStackSlotPostFE - Check for post-frame ptr elimination
125 /// stack locations as well. This uses a heuristic so it isn't
126 /// reliable for correctness.
127 virtual unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
128 int &FrameIndex) const {
132 /// hasLoadFromStackSlot - If the specified machine instruction has
133 /// a load from a stack slot, return true along with the FrameIndex
134 /// of the loaded stack slot and the machine mem operand containing
135 /// the reference. If not, return false. Unlike
136 /// isLoadFromStackSlot, this returns true for any instructions that
137 /// loads from the stack. This is just a hint, as some cases may be
139 virtual bool hasLoadFromStackSlot(const MachineInstr *MI,
140 const MachineMemOperand *&MMO,
141 int &FrameIndex) const {
145 /// isStoreToStackSlot - If the specified machine instruction is a direct
146 /// store to a stack slot, return the virtual or physical register number of
147 /// the source reg along with the FrameIndex of the loaded stack slot. If
148 /// not, return 0. This predicate must return 0 if the instruction has
149 /// any side effects other than storing to the stack slot.
150 virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
151 int &FrameIndex) const {
155 /// isStoreToStackSlotPostFE - Check for post-frame ptr elimination
156 /// stack locations as well. This uses a heuristic so it isn't
157 /// reliable for correctness.
158 virtual unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
159 int &FrameIndex) const {
163 /// hasStoreToStackSlot - If the specified machine instruction has a
164 /// store to a stack slot, return true along with the FrameIndex of
165 /// the loaded stack slot and the machine mem operand containing the
166 /// reference. If not, return false. Unlike isStoreToStackSlot,
167 /// this returns true for any instructions that stores to the
168 /// stack. This is just a hint, as some cases may be missed.
169 virtual bool hasStoreToStackSlot(const MachineInstr *MI,
170 const MachineMemOperand *&MMO,
171 int &FrameIndex) const {
175 /// reMaterialize - Re-issue the specified 'original' instruction at the
176 /// specific location targeting a new destination register.
177 /// The register in Orig->getOperand(0).getReg() will be substituted by
178 /// DestReg:SubIdx. Any existing subreg index is preserved or composed with
180 virtual void reMaterialize(MachineBasicBlock &MBB,
181 MachineBasicBlock::iterator MI,
182 unsigned DestReg, unsigned SubIdx,
183 const MachineInstr *Orig,
184 const TargetRegisterInfo &TRI) const = 0;
186 /// scheduleTwoAddrSource - Schedule the copy / re-mat of the source of the
187 /// two-addrss instruction inserted by two-address pass.
188 virtual void scheduleTwoAddrSource(MachineInstr *SrcMI,
190 const TargetRegisterInfo &TRI) const {
194 /// duplicate - Create a duplicate of the Orig instruction in MF. This is like
195 /// MachineFunction::CloneMachineInstr(), but the target may update operands
196 /// that are required to be unique.
198 /// The instruction must be duplicable as indicated by isNotDuplicable().
199 virtual MachineInstr *duplicate(MachineInstr *Orig,
200 MachineFunction &MF) const = 0;
202 /// convertToThreeAddress - This method must be implemented by targets that
203 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
204 /// may be able to convert a two-address instruction into one or more true
205 /// three-address instructions on demand. This allows the X86 target (for
206 /// example) to convert ADD and SHL instructions into LEA instructions if they
207 /// would require register copies due to two-addressness.
209 /// This method returns a null pointer if the transformation cannot be
210 /// performed, otherwise it returns the last new instruction.
212 virtual MachineInstr *
213 convertToThreeAddress(MachineFunction::iterator &MFI,
214 MachineBasicBlock::iterator &MBBI, LiveVariables *LV) const {
218 /// commuteInstruction - If a target has any instructions that are
219 /// commutable but require converting to different instructions or making
220 /// non-trivial changes to commute them, this method can overloaded to do
221 /// that. The default implementation simply swaps the commutable operands.
222 /// If NewMI is false, MI is modified in place and returned; otherwise, a
223 /// new machine instruction is created and returned. Do not call this
224 /// method for a non-commutable instruction, but there may be some cases
225 /// where this method fails and returns null.
226 virtual MachineInstr *commuteInstruction(MachineInstr *MI,
227 bool NewMI = false) const = 0;
229 /// findCommutedOpIndices - If specified MI is commutable, return the two
230 /// operand indices that would swap value. Return false if the instruction
231 /// is not in a form which this routine understands.
232 virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1,
233 unsigned &SrcOpIdx2) const = 0;
235 /// produceSameValue - Return true if two machine instructions would produce
236 /// identical values. By default, this is only true when the two instructions
237 /// are deemed identical except for defs. If this function is called when the
238 /// IR is still in SSA form, the caller can pass the MachineRegisterInfo for
239 /// aggressive checks.
240 virtual bool produceSameValue(const MachineInstr *MI0,
241 const MachineInstr *MI1,
242 const MachineRegisterInfo *MRI = 0) const = 0;
244 /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
245 /// true if it cannot be understood (e.g. it's a switch dispatch or isn't
246 /// implemented for a target). Upon success, this returns false and returns
247 /// with the following information in various cases:
249 /// 1. If this block ends with no branches (it just falls through to its succ)
250 /// just return false, leaving TBB/FBB null.
251 /// 2. If this block ends with only an unconditional branch, it sets TBB to be
252 /// the destination block.
253 /// 3. If this block ends with a conditional branch and it falls through to a
254 /// successor block, it sets TBB to be the branch destination block and a
255 /// list of operands that evaluate the condition. These operands can be
256 /// passed to other TargetInstrInfo methods to create new branches.
257 /// 4. If this block ends with a conditional branch followed by an
258 /// unconditional branch, it returns the 'true' destination in TBB, the
259 /// 'false' destination in FBB, and a list of operands that evaluate the
260 /// condition. These operands can be passed to other TargetInstrInfo
261 /// methods to create new branches.
263 /// Note that RemoveBranch and InsertBranch must be implemented to support
264 /// cases where this method returns success.
266 /// If AllowModify is true, then this routine is allowed to modify the basic
267 /// block (e.g. delete instructions after the unconditional branch).
269 virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
270 MachineBasicBlock *&FBB,
271 SmallVectorImpl<MachineOperand> &Cond,
272 bool AllowModify = false) const {
276 /// RemoveBranch - Remove the branching code at the end of the specific MBB.
277 /// This is only invoked in cases where AnalyzeBranch returns success. It
278 /// returns the number of instructions that were removed.
279 virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const {
280 assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!");
284 /// InsertBranch - Insert branch code into the end of the specified
285 /// MachineBasicBlock. The operands to this method are the same as those
286 /// returned by AnalyzeBranch. This is only invoked in cases where
287 /// AnalyzeBranch returns success. It returns the number of instructions
290 /// It is also invoked by tail merging to add unconditional branches in
291 /// cases where AnalyzeBranch doesn't apply because there was no original
292 /// branch to analyze. At least this much must be implemented, else tail
293 /// merging needs to be disabled.
294 virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
295 MachineBasicBlock *FBB,
296 const SmallVectorImpl<MachineOperand> &Cond,
298 assert(0 && "Target didn't implement TargetInstrInfo::InsertBranch!");
302 /// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything
303 /// after it, replacing it with an unconditional branch to NewDest. This is
304 /// used by the tail merging pass.
305 virtual void ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
306 MachineBasicBlock *NewDest) const = 0;
308 /// isLegalToSplitMBBAt - Return true if it's legal to split the given basic
309 /// block at the specified instruction (i.e. instruction would be the start
310 /// of a new basic block).
311 virtual bool isLegalToSplitMBBAt(MachineBasicBlock &MBB,
312 MachineBasicBlock::iterator MBBI) const {
316 /// isProfitableToIfCvt - Return true if it's profitable to predicate
317 /// instructions with accumulated instruction latency of "NumCycles"
318 /// of the specified basic block, where the probability of the instructions
319 /// being executed is given by Probability, and Confidence is a measure
320 /// of our confidence that it will be properly predicted.
322 bool isProfitableToIfCvt(MachineBasicBlock &MBB, unsigned NumCyles,
323 unsigned ExtraPredCycles,
324 float Probability, float Confidence) const {
328 /// isProfitableToIfCvt - Second variant of isProfitableToIfCvt, this one
329 /// checks for the case where two basic blocks from true and false path
330 /// of a if-then-else (diamond) are predicated on mutally exclusive
331 /// predicates, where the probability of the true path being taken is given
332 /// by Probability, and Confidence is a measure of our confidence that it
333 /// will be properly predicted.
335 isProfitableToIfCvt(MachineBasicBlock &TMBB,
336 unsigned NumTCycles, unsigned ExtraTCycles,
337 MachineBasicBlock &FMBB,
338 unsigned NumFCycles, unsigned ExtraFCycles,
339 float Probability, float Confidence) const {
343 /// isProfitableToDupForIfCvt - Return true if it's profitable for
344 /// if-converter to duplicate instructions of specified accumulated
345 /// instruction latencies in the specified MBB to enable if-conversion.
346 /// The probability of the instructions being executed is given by
347 /// Probability, and Confidence is a measure of our confidence that it
348 /// will be properly predicted.
350 isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCyles,
351 float Probability, float Confidence) const {
355 /// copyPhysReg - Emit instructions to copy a pair of physical registers.
356 virtual void copyPhysReg(MachineBasicBlock &MBB,
357 MachineBasicBlock::iterator MI, DebugLoc DL,
358 unsigned DestReg, unsigned SrcReg,
359 bool KillSrc) const {
360 assert(0 && "Target didn't implement TargetInstrInfo::copyPhysReg!");
363 /// storeRegToStackSlot - Store the specified register of the given register
364 /// class to the specified stack frame index. The store instruction is to be
365 /// added to the given machine basic block before the specified machine
366 /// instruction. If isKill is true, the register operand is the last use and
367 /// must be marked kill.
368 virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
369 MachineBasicBlock::iterator MI,
370 unsigned SrcReg, bool isKill, int FrameIndex,
371 const TargetRegisterClass *RC,
372 const TargetRegisterInfo *TRI) const {
373 assert(0 && "Target didn't implement TargetInstrInfo::storeRegToStackSlot!");
376 /// loadRegFromStackSlot - Load the specified register of the given register
377 /// class from the specified stack frame index. The load instruction is to be
378 /// added to the given machine basic block before the specified machine
380 virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
381 MachineBasicBlock::iterator MI,
382 unsigned DestReg, int FrameIndex,
383 const TargetRegisterClass *RC,
384 const TargetRegisterInfo *TRI) const {
385 assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromStackSlot!");
388 /// emitFrameIndexDebugValue - Emit a target-dependent form of
389 /// DBG_VALUE encoding the address of a frame index. Addresses would
390 /// normally be lowered the same way as other addresses on the target,
391 /// e.g. in load instructions. For targets that do not support this
392 /// the debug info is simply lost.
393 /// If you add this for a target you should handle this DBG_VALUE in the
394 /// target-specific AsmPrinter code as well; you will probably get invalid
395 /// assembly output if you don't.
396 virtual MachineInstr *emitFrameIndexDebugValue(MachineFunction &MF,
404 /// foldMemoryOperand - Attempt to fold a load or store of the specified stack
405 /// slot into the specified machine instruction for the specified operand(s).
406 /// If this is possible, a new instruction is returned with the specified
407 /// operand folded, otherwise NULL is returned.
408 /// The new instruction is inserted before MI, and the client is responsible
409 /// for removing the old instruction.
410 MachineInstr* foldMemoryOperand(MachineBasicBlock::iterator MI,
411 const SmallVectorImpl<unsigned> &Ops,
412 int FrameIndex) const;
414 /// foldMemoryOperand - Same as the previous version except it allows folding
415 /// of any load and store from / to any address, not just from a specific
417 MachineInstr* foldMemoryOperand(MachineBasicBlock::iterator MI,
418 const SmallVectorImpl<unsigned> &Ops,
419 MachineInstr* LoadMI) const;
422 /// foldMemoryOperandImpl - Target-dependent implementation for
423 /// foldMemoryOperand. Target-independent code in foldMemoryOperand will
424 /// take care of adding a MachineMemOperand to the newly created instruction.
425 virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
427 const SmallVectorImpl<unsigned> &Ops,
428 int FrameIndex) const {
432 /// foldMemoryOperandImpl - Target-dependent implementation for
433 /// foldMemoryOperand. Target-independent code in foldMemoryOperand will
434 /// take care of adding a MachineMemOperand to the newly created instruction.
435 virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
437 const SmallVectorImpl<unsigned> &Ops,
438 MachineInstr* LoadMI) const {
443 /// canFoldMemoryOperand - Returns true for the specified load / store if
444 /// folding is possible.
446 bool canFoldMemoryOperand(const MachineInstr *MI,
447 const SmallVectorImpl<unsigned> &Ops) const =0;
449 /// unfoldMemoryOperand - Separate a single instruction which folded a load or
450 /// a store or a load and a store into two or more instruction. If this is
451 /// possible, returns true as well as the new instructions by reference.
452 virtual bool unfoldMemoryOperand(MachineFunction &MF, MachineInstr *MI,
453 unsigned Reg, bool UnfoldLoad, bool UnfoldStore,
454 SmallVectorImpl<MachineInstr*> &NewMIs) const{
458 virtual bool unfoldMemoryOperand(SelectionDAG &DAG, SDNode *N,
459 SmallVectorImpl<SDNode*> &NewNodes) const {
463 /// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new
464 /// instruction after load / store are unfolded from an instruction of the
465 /// specified opcode. It returns zero if the specified unfolding is not
466 /// possible. If LoadRegIndex is non-null, it is filled in with the operand
467 /// index of the operand which will hold the register holding the loaded
469 virtual unsigned getOpcodeAfterMemoryUnfold(unsigned Opc,
470 bool UnfoldLoad, bool UnfoldStore,
471 unsigned *LoadRegIndex = 0) const {
475 /// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler
476 /// to determine if two loads are loading from the same base address. It
477 /// should only return true if the base pointers are the same and the
478 /// only differences between the two addresses are the offset. It also returns
479 /// the offsets by reference.
480 virtual bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2,
481 int64_t &Offset1, int64_t &Offset2) const {
485 /// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
486 /// determine (in conjunction with areLoadsFromSameBasePtr) if two loads should
487 /// be scheduled togther. On some targets if two loads are loading from
488 /// addresses in the same cache line, it's better if they are scheduled
489 /// together. This function takes two integers that represent the load offsets
490 /// from the common base address. It returns true if it decides it's desirable
491 /// to schedule the two loads together. "NumLoads" is the number of loads that
492 /// have already been scheduled after Load1.
493 virtual bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
494 int64_t Offset1, int64_t Offset2,
495 unsigned NumLoads) const {
499 /// ReverseBranchCondition - Reverses the branch condition of the specified
500 /// condition list, returning false on success and true if it cannot be
503 bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const {
507 /// insertNoop - Insert a noop into the instruction stream at the specified
509 virtual void insertNoop(MachineBasicBlock &MBB,
510 MachineBasicBlock::iterator MI) const;
513 /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
514 virtual void getNoopForMachoTarget(MCInst &NopInst) const {
515 // Default to just using 'nop' string.
519 /// isPredicated - Returns true if the instruction is already predicated.
521 virtual bool isPredicated(const MachineInstr *MI) const {
525 /// isUnpredicatedTerminator - Returns true if the instruction is a
526 /// terminator instruction that has not been predicated.
527 virtual bool isUnpredicatedTerminator(const MachineInstr *MI) const;
529 /// PredicateInstruction - Convert the instruction into a predicated
530 /// instruction. It returns true if the operation was successful.
532 bool PredicateInstruction(MachineInstr *MI,
533 const SmallVectorImpl<MachineOperand> &Pred) const = 0;
535 /// SubsumesPredicate - Returns true if the first specified predicate
536 /// subsumes the second, e.g. GE subsumes GT.
538 bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
539 const SmallVectorImpl<MachineOperand> &Pred2) const {
543 /// DefinesPredicate - If the specified instruction defines any predicate
544 /// or condition code register(s) used for predication, returns true as well
545 /// as the definition predicate(s) by reference.
546 virtual bool DefinesPredicate(MachineInstr *MI,
547 std::vector<MachineOperand> &Pred) const {
551 /// isPredicable - Return true if the specified instruction can be predicated.
552 /// By default, this returns true for every instruction with a
553 /// PredicateOperand.
554 virtual bool isPredicable(MachineInstr *MI) const {
555 return MI->getDesc().isPredicable();
558 /// isSafeToMoveRegClassDefs - Return true if it's safe to move a machine
559 /// instruction that defines the specified register class.
560 virtual bool isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const {
564 /// isSchedulingBoundary - Test if the given instruction should be
565 /// considered a scheduling boundary. This primarily includes labels and
567 virtual bool isSchedulingBoundary(const MachineInstr *MI,
568 const MachineBasicBlock *MBB,
569 const MachineFunction &MF) const = 0;
571 /// Measure the specified inline asm to determine an approximation of its
573 virtual unsigned getInlineAsmLength(const char *Str,
574 const MCAsmInfo &MAI) const;
576 /// CreateTargetHazardRecognizer - Allocate and return a hazard recognizer to
577 /// use for this target when scheduling the machine instructions before
578 /// register allocation.
579 virtual ScheduleHazardRecognizer*
580 CreateTargetHazardRecognizer(const TargetMachine *TM,
581 const ScheduleDAG *DAG) const = 0;
583 /// CreateTargetPostRAHazardRecognizer - Allocate and return a hazard
584 /// recognizer to use for this target when scheduling the machine instructions
585 /// after register allocation.
586 virtual ScheduleHazardRecognizer*
587 CreateTargetPostRAHazardRecognizer(const InstrItineraryData*,
588 const ScheduleDAG *DAG) const = 0;
590 /// AnalyzeCompare - For a comparison instruction, return the source register
591 /// in SrcReg and the value it compares against in CmpValue. Return true if
592 /// the comparison instruction can be analyzed.
593 virtual bool AnalyzeCompare(const MachineInstr *MI,
594 unsigned &SrcReg, int &Mask, int &Value) const {
598 /// OptimizeCompareInstr - See if the comparison instruction can be converted
599 /// into something more efficient. E.g., on ARM most instructions can set the
600 /// flags register, obviating the need for a separate CMP.
601 virtual bool OptimizeCompareInstr(MachineInstr *CmpInstr,
602 unsigned SrcReg, int Mask, int Value,
603 const MachineRegisterInfo *MRI) const {
607 /// FoldImmediate - 'Reg' is known to be defined by a move immediate
608 /// instruction, try to fold the immediate into the use instruction.
609 virtual bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
610 unsigned Reg, MachineRegisterInfo *MRI) const {
614 /// getNumMicroOps - Return the number of u-operations the given machine
615 /// instruction will be decoded to on the target cpu.
616 virtual unsigned getNumMicroOps(const InstrItineraryData *ItinData,
617 const MachineInstr *MI) const;
619 /// isZeroCost - Return true for pseudo instructions that don't consume any
620 /// machine resources in their current form. These are common cases that the
621 /// scheduler should consider free, rather than conservatively handling them
622 /// as instructions with no itinerary.
623 bool isZeroCost(unsigned Opcode) const {
624 return Opcode <= TargetOpcode::COPY;
627 /// getOperandLatency - Compute and return the use operand latency of a given
628 /// pair of def and use.
629 /// In most cases, the static scheduling itinerary was enough to determine the
630 /// operand latency. But it may not be possible for instructions with variable
631 /// number of defs / uses.
632 virtual int getOperandLatency(const InstrItineraryData *ItinData,
633 const MachineInstr *DefMI, unsigned DefIdx,
634 const MachineInstr *UseMI, unsigned UseIdx) const;
636 virtual int getOperandLatency(const InstrItineraryData *ItinData,
637 SDNode *DefNode, unsigned DefIdx,
638 SDNode *UseNode, unsigned UseIdx) const;
640 /// getInstrLatency - Compute the instruction latency of a given instruction.
641 /// If the instruction has higher cost when predicated, it's returned via
643 virtual int getInstrLatency(const InstrItineraryData *ItinData,
644 const MachineInstr *MI,
645 unsigned *PredCost = 0) const;
647 virtual int getInstrLatency(const InstrItineraryData *ItinData,
650 /// isHighLatencyDef - Return true if this opcode has high latency to its
652 virtual bool isHighLatencyDef(int opc) const { return false; }
654 /// hasHighOperandLatency - Compute operand latency between a def of 'Reg'
655 /// and an use in the current loop, return true if the target considered
656 /// it 'high'. This is used by optimization passes such as machine LICM to
657 /// determine whether it makes sense to hoist an instruction out even in
658 /// high register pressure situation.
660 bool hasHighOperandLatency(const InstrItineraryData *ItinData,
661 const MachineRegisterInfo *MRI,
662 const MachineInstr *DefMI, unsigned DefIdx,
663 const MachineInstr *UseMI, unsigned UseIdx) const {
667 /// hasLowDefLatency - Compute operand latency of a def of 'Reg', return true
668 /// if the target considered it 'low'.
670 bool hasLowDefLatency(const InstrItineraryData *ItinData,
671 const MachineInstr *DefMI, unsigned DefIdx) const;
674 int CallFrameSetupOpcode, CallFrameDestroyOpcode;
677 /// TargetInstrInfoImpl - This is the default implementation of
678 /// TargetInstrInfo, which just provides a couple of default implementations
679 /// for various methods. This separated out because it is implemented in
680 /// libcodegen, not in libtarget.
681 class TargetInstrInfoImpl : public TargetInstrInfo {
683 TargetInstrInfoImpl(int CallFrameSetupOpcode = -1,
684 int CallFrameDestroyOpcode = -1)
685 : TargetInstrInfo(CallFrameSetupOpcode, CallFrameDestroyOpcode) {}
687 virtual void ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
688 MachineBasicBlock *NewDest) const;
689 virtual MachineInstr *commuteInstruction(MachineInstr *MI,
690 bool NewMI = false) const;
691 virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1,
692 unsigned &SrcOpIdx2) const;
693 virtual bool canFoldMemoryOperand(const MachineInstr *MI,
694 const SmallVectorImpl<unsigned> &Ops) const;
695 virtual bool PredicateInstruction(MachineInstr *MI,
696 const SmallVectorImpl<MachineOperand> &Pred) const;
697 virtual void reMaterialize(MachineBasicBlock &MBB,
698 MachineBasicBlock::iterator MI,
699 unsigned DestReg, unsigned SubReg,
700 const MachineInstr *Orig,
701 const TargetRegisterInfo &TRI) const;
702 virtual MachineInstr *duplicate(MachineInstr *Orig,
703 MachineFunction &MF) const;
704 virtual bool produceSameValue(const MachineInstr *MI0,
705 const MachineInstr *MI1,
706 const MachineRegisterInfo *MRI) const;
707 virtual bool isSchedulingBoundary(const MachineInstr *MI,
708 const MachineBasicBlock *MBB,
709 const MachineFunction &MF) const;
711 bool usePreRAHazardRecognizer() const;
713 virtual ScheduleHazardRecognizer *
714 CreateTargetHazardRecognizer(const TargetMachine*, const ScheduleDAG*) const;
716 virtual ScheduleHazardRecognizer *
717 CreateTargetPostRAHazardRecognizer(const InstrItineraryData*,
718 const ScheduleDAG*) const;
721 } // End llvm namespace