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 instructions to the code generator.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TARGET_TARGETINSTRINFO_H
15 #define LLVM_TARGET_TARGETINSTRINFO_H
17 #include "llvm/CodeGen/MachineBasicBlock.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/Support/DataTypes.h"
27 class TargetRegisterClass;
29 class CalleeSavedInfo;
31 template<class T> class SmallVectorImpl;
33 //---------------------------------------------------------------------------
34 // Data types used to define information about a single machine instruction
35 //---------------------------------------------------------------------------
37 typedef short MachineOpCode;
38 typedef unsigned InstrSchedClass;
40 //---------------------------------------------------------------------------
41 // struct TargetInstrDescriptor:
42 // Predefined information about each machine instruction.
43 // Designed to initialized statically.
46 const unsigned M_BRANCH_FLAG = 1 << 0;
47 const unsigned M_CALL_FLAG = 1 << 1;
48 const unsigned M_RET_FLAG = 1 << 2;
49 const unsigned M_BARRIER_FLAG = 1 << 3;
50 const unsigned M_DELAY_SLOT_FLAG = 1 << 4;
52 /// M_SIMPLE_LOAD_FLAG - This flag is set for instructions that are simple loads
53 /// from memory. This should only be set on instructions that load a value from
54 /// memory and return it in their only virtual register definition.
55 const unsigned M_SIMPLE_LOAD_FLAG = 1 << 5;
57 /// M_MAY_STORE_FLAG - This flag is set to any instruction that could possibly
58 /// modify memory. Instructions with this flag set are not necessarily simple
59 /// store instructions, they may store a modified value based on their operands,
60 /// or may not actually modify anything, for example.
61 const unsigned M_MAY_STORE_FLAG = 1 << 6;
63 const unsigned M_INDIRECT_FLAG = 1 << 7;
64 const unsigned M_IMPLICIT_DEF_FLAG = 1 << 8;
66 // M_CONVERTIBLE_TO_3_ADDR - This is a 2-address instruction which can be
67 // changed into a 3-address instruction if the first two operands cannot be
68 // assigned to the same register. The target must implement the
69 // TargetInstrInfo::convertToThreeAddress method for this instruction.
70 const unsigned M_CONVERTIBLE_TO_3_ADDR = 1 << 9;
72 // This M_COMMUTABLE - is a 2- or 3-address instruction (of the form X = op Y,
73 // Z), which produces the same result if Y and Z are exchanged.
74 const unsigned M_COMMUTABLE = 1 << 10;
76 // M_TERMINATOR_FLAG - Is this instruction part of the terminator for a basic
77 // block? Typically this is things like return and branch instructions.
78 // Various passes use this to insert code into the bottom of a basic block, but
79 // before control flow occurs.
80 const unsigned M_TERMINATOR_FLAG = 1 << 11;
82 // M_USES_CUSTOM_DAG_SCHED_INSERTION - Set if this instruction requires custom
83 // insertion support when the DAG scheduler is inserting it into a machine basic
85 const unsigned M_USES_CUSTOM_DAG_SCHED_INSERTION = 1 << 12;
87 // M_VARIABLE_OPS - Set if this instruction can have a variable number of extra
88 // operands in addition to the minimum number operands specified.
89 const unsigned M_VARIABLE_OPS = 1 << 13;
91 // M_PREDICABLE - Set if this instruction has a predicate operand that
92 // controls execution. It may be set to 'always'.
93 const unsigned M_PREDICABLE = 1 << 14;
95 // M_REMATERIALIZIBLE - Set if this instruction can be trivally re-materialized
96 // at any time, e.g. constant generation, load from constant pool.
97 const unsigned M_REMATERIALIZIBLE = 1 << 15;
99 // M_NOT_DUPLICABLE - Set if this instruction cannot be safely duplicated.
100 // (e.g. instructions with unique labels attached).
101 const unsigned M_NOT_DUPLICABLE = 1 << 16;
103 // M_HAS_OPTIONAL_DEF - Set if this instruction has an optional definition, e.g.
104 // ARM instructions which can set condition code if 's' bit is set.
105 const unsigned M_HAS_OPTIONAL_DEF = 1 << 17;
107 // M_NEVER_HAS_SIDE_EFFECTS - Set if this instruction has no side effects that
108 // are not captured by any operands of the instruction or other flags, and when
109 // *all* instances of the instruction of that opcode have no side effects.
111 // Note: This and M_MAY_HAVE_SIDE_EFFECTS are mutually exclusive. You can't set
112 // both! If neither flag is set, then the instruction *always* has side effects.
113 const unsigned M_NEVER_HAS_SIDE_EFFECTS = 1 << 18;
115 // M_MAY_HAVE_SIDE_EFFECTS - Set if some instances of this instruction can have
116 // side effects. The virtual method "isReallySideEffectFree" is called to
117 // determine this. Load instructions are an example of where this is useful. In
118 // general, loads always have side effects. However, loads from constant pools
119 // don't. We let the specific back end make this determination.
121 // Note: This and M_NEVER_HAS_SIDE_EFFECTS are mutually exclusive. You can't set
122 // both! If neither flag is set, then the instruction *always* has side effects.
123 const unsigned M_MAY_HAVE_SIDE_EFFECTS = 1 << 19;
125 // Machine operand flags
126 // M_LOOK_UP_PTR_REG_CLASS - Set if this operand is a pointer value and it
127 // requires a callback to look up its register class.
128 const unsigned M_LOOK_UP_PTR_REG_CLASS = 1 << 0;
130 /// M_PREDICATE_OPERAND - Set if this is one of the operands that made up of the
131 /// predicate operand that controls an M_PREDICATED instruction.
132 const unsigned M_PREDICATE_OPERAND = 1 << 1;
134 /// M_OPTIONAL_DEF_OPERAND - Set if this operand is a optional def.
136 const unsigned M_OPTIONAL_DEF_OPERAND = 1 << 2;
139 // Operand constraints: only "tied_to" for now.
140 enum OperandConstraint {
141 TIED_TO = 0 // Must be allocated the same register as.
145 /// TargetOperandInfo - This holds information about one operand of a machine
146 /// instruction, indicating the register class for register operands, etc.
148 class TargetOperandInfo {
150 /// RegClass - This specifies the register class enumeration of the operand
151 /// if the operand is a register. If not, this contains 0.
152 unsigned short RegClass;
153 unsigned short Flags;
154 /// Lower 16 bits are used to specify which constraints are set. The higher 16
155 /// bits are used to specify the value of constraints (4 bits each).
156 unsigned int Constraints;
157 /// Currently no other information.
161 class TargetInstrDescriptor {
163 MachineOpCode Opcode; // The opcode.
164 unsigned short numOperands; // Num of args (may be more if variable_ops).
165 unsigned short numDefs; // Num of args that are definitions.
166 const char * Name; // Assembly language mnemonic for the opcode.
167 InstrSchedClass schedClass; // enum identifying instr sched class
168 unsigned Flags; // flags identifying machine instr class
169 unsigned TSFlags; // Target Specific Flag values
170 const unsigned *ImplicitUses; // Registers implicitly read by this instr
171 const unsigned *ImplicitDefs; // Registers implicitly defined by this instr
172 const TargetOperandInfo *OpInfo; // 'numOperands' entries about operands.
174 /// getOperandConstraint - Returns the value of the specific constraint if
175 /// it is set. Returns -1 if it is not set.
176 int getOperandConstraint(unsigned OpNum,
177 TOI::OperandConstraint Constraint) const {
178 assert((OpNum < numOperands || (Flags & M_VARIABLE_OPS)) &&
179 "Invalid operand # of TargetInstrInfo");
180 if (OpNum < numOperands &&
181 (OpInfo[OpNum].Constraints & (1 << Constraint))) {
182 unsigned Pos = 16 + Constraint * 4;
183 return (int)(OpInfo[OpNum].Constraints >> Pos) & 0xf;
188 /// findTiedToSrcOperand - Returns the operand that is tied to the specified
189 /// dest operand. Returns -1 if there isn't one.
190 int findTiedToSrcOperand(unsigned OpNum) const;
193 /// isSimpleLoad - Return true for instructions that are simple loads from
194 /// memory. This should only be set on instructions that load a value from
195 /// memory and return it in their only virtual register definition.
196 /// Instructions that return a value loaded from memory and then modified in
197 /// some way should not return true for this.
198 bool isSimpleLoad() const {
199 return Flags & M_SIMPLE_LOAD_FLAG;
205 //---------------------------------------------------------------------------
207 /// TargetInstrInfo - Interface to description of machine instructions
209 class TargetInstrInfo {
210 const TargetInstrDescriptor* desc; // raw array to allow static init'n
211 unsigned NumOpcodes; // number of entries in the desc array
212 unsigned numRealOpCodes; // number of non-dummy op codes
214 TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT
215 void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT
217 TargetInstrInfo(const TargetInstrDescriptor *desc, unsigned NumOpcodes);
218 virtual ~TargetInstrInfo();
220 // Invariant opcodes: All instruction sets have these as their low opcodes.
229 unsigned getNumOpcodes() const { return NumOpcodes; }
231 /// get - Return the machine instruction descriptor that corresponds to the
232 /// specified instruction opcode.
234 const TargetInstrDescriptor& get(MachineOpCode Opcode) const {
235 assert((unsigned)Opcode < NumOpcodes);
239 const char *getName(MachineOpCode Opcode) const {
240 return get(Opcode).Name;
243 int getNumOperands(MachineOpCode Opcode) const {
244 return get(Opcode).numOperands;
247 int getNumDefs(MachineOpCode Opcode) const {
248 return get(Opcode).numDefs;
251 InstrSchedClass getSchedClass(MachineOpCode Opcode) const {
252 return get(Opcode).schedClass;
255 const unsigned *getImplicitUses(MachineOpCode Opcode) const {
256 return get(Opcode).ImplicitUses;
259 const unsigned *getImplicitDefs(MachineOpCode Opcode) const {
260 return get(Opcode).ImplicitDefs;
265 // Query instruction class flags according to the machine-independent
266 // flags listed above.
268 bool isReturn(MachineOpCode Opcode) const {
269 return get(Opcode).Flags & M_RET_FLAG;
272 bool isCommutableInstr(MachineOpCode Opcode) const {
273 return get(Opcode).Flags & M_COMMUTABLE;
275 bool isTerminatorInstr(MachineOpCode Opcode) const {
276 return get(Opcode).Flags & M_TERMINATOR_FLAG;
279 bool isBranch(MachineOpCode Opcode) const {
280 return get(Opcode).Flags & M_BRANCH_FLAG;
283 bool isIndirectBranch(MachineOpCode Opcode) const {
284 return get(Opcode).Flags & M_INDIRECT_FLAG;
287 /// isBarrier - Returns true if the specified instruction stops control flow
288 /// from executing the instruction immediately following it. Examples include
289 /// unconditional branches and return instructions.
290 bool isBarrier(MachineOpCode Opcode) const {
291 return get(Opcode).Flags & M_BARRIER_FLAG;
294 bool isCall(MachineOpCode Opcode) const {
295 return get(Opcode).Flags & M_CALL_FLAG;
298 /// mayStore - Return true if this instruction could possibly modify memory.
299 /// Instructions with this flag set are not necessarily simple store
300 /// instructions, they may store a modified value based on their operands, or
301 /// may not actually modify anything, for example.
302 bool mayStore(MachineOpCode Opcode) const {
303 return get(Opcode).Flags & M_MAY_STORE_FLAG;
306 /// hasDelaySlot - Returns true if the specified instruction has a delay slot
307 /// which must be filled by the code generator.
308 bool hasDelaySlot(MachineOpCode Opcode) const {
309 return get(Opcode).Flags & M_DELAY_SLOT_FLAG;
312 /// usesCustomDAGSchedInsertionHook - Return true if this instruction requires
313 /// custom insertion support when the DAG scheduler is inserting it into a
314 /// machine basic block.
315 bool usesCustomDAGSchedInsertionHook(MachineOpCode Opcode) const {
316 return get(Opcode).Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION;
319 bool hasVariableOperands(MachineOpCode Opcode) const {
320 return get(Opcode).Flags & M_VARIABLE_OPS;
323 bool isPredicable(MachineOpCode Opcode) const {
324 return get(Opcode).Flags & M_PREDICABLE;
327 bool isNotDuplicable(MachineOpCode Opcode) const {
328 return get(Opcode).Flags & M_NOT_DUPLICABLE;
331 bool hasOptionalDef(MachineOpCode Opcode) const {
332 return get(Opcode).Flags & M_HAS_OPTIONAL_DEF;
335 /// isTriviallyReMaterializable - Return true if the instruction is trivially
336 /// rematerializable, meaning it has no side effects and requires no operands
337 /// that aren't always available.
338 bool isTriviallyReMaterializable(MachineInstr *MI) const {
339 return (MI->getInstrDescriptor()->Flags & M_REMATERIALIZIBLE) &&
340 isReallyTriviallyReMaterializable(MI);
343 /// hasUnmodelledSideEffects - Returns true if the instruction has side
344 /// effects that are not captured by any operands of the instruction or other
346 bool hasUnmodelledSideEffects(MachineInstr *MI) const {
347 const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
348 if (TID->Flags & M_NEVER_HAS_SIDE_EFFECTS) return false;
349 if (!(TID->Flags & M_MAY_HAVE_SIDE_EFFECTS)) return true;
350 return !isReallySideEffectFree(MI); // May have side effects
353 /// isReallyTriviallyReMaterializable - For instructions with opcodes for
354 /// which the M_REMATERIALIZABLE flag is set, this function tests whether the
355 /// instruction itself is actually trivially rematerializable, considering
356 /// its operands. This is used for targets that have instructions that are
357 /// only trivially rematerializable for specific uses. This predicate must
358 /// return false if the instruction has any side effects other than
359 /// producing a value, or if it requres any address registers that are not
360 /// always available.
361 virtual bool isReallyTriviallyReMaterializable(MachineInstr *MI) const {
365 /// isReallySideEffectFree - If the M_MAY_HAVE_SIDE_EFFECTS flag is set, this
366 /// method is called to determine if the specific instance of this
367 /// instruction has side effects. This is useful in cases of instructions,
368 /// like loads, which generally always have side effects. A load from a
369 /// constant pool doesn't have side effects, though. So we need to
370 /// differentiate it from the general case.
371 virtual bool isReallySideEffectFree(MachineInstr *MI) const {
375 /// getOperandConstraint - Returns the value of the specific constraint if
376 /// it is set. Returns -1 if it is not set.
377 int getOperandConstraint(MachineOpCode Opcode, unsigned OpNum,
378 TOI::OperandConstraint Constraint) const {
379 return get(Opcode).getOperandConstraint(OpNum, Constraint);
382 /// Return true if the instruction is a register to register move
383 /// and leave the source and dest operands in the passed parameters.
384 virtual bool isMoveInstr(const MachineInstr& MI,
386 unsigned& destReg) const {
390 /// isLoadFromStackSlot - If the specified machine instruction is a direct
391 /// load from a stack slot, return the virtual or physical register number of
392 /// the destination along with the FrameIndex of the loaded stack slot. If
393 /// not, return 0. This predicate must return 0 if the instruction has
394 /// any side effects other than loading from the stack slot.
395 virtual unsigned isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const{
399 /// isStoreToStackSlot - If the specified machine instruction is a direct
400 /// store to a stack slot, return the virtual or physical register number of
401 /// the source reg along with the FrameIndex of the loaded stack slot. If
402 /// not, return 0. This predicate must return 0 if the instruction has
403 /// any side effects other than storing to the stack slot.
404 virtual unsigned isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
408 /// convertToThreeAddress - This method must be implemented by targets that
409 /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
410 /// may be able to convert a two-address instruction into one or more true
411 /// three-address instructions on demand. This allows the X86 target (for
412 /// example) to convert ADD and SHL instructions into LEA instructions if they
413 /// would require register copies due to two-addressness.
415 /// This method returns a null pointer if the transformation cannot be
416 /// performed, otherwise it returns the last new instruction.
418 virtual MachineInstr *
419 convertToThreeAddress(MachineFunction::iterator &MFI,
420 MachineBasicBlock::iterator &MBBI, LiveVariables &LV) const {
424 /// commuteInstruction - If a target has any instructions that are commutable,
425 /// but require converting to a different instruction or making non-trivial
426 /// changes to commute them, this method can overloaded to do this. The
427 /// default implementation of this method simply swaps the first two operands
428 /// of MI and returns it.
430 /// If a target wants to make more aggressive changes, they can construct and
431 /// return a new machine instruction. If an instruction cannot commute, it
432 /// can also return null.
434 virtual MachineInstr *commuteInstruction(MachineInstr *MI) const = 0;
436 /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
437 /// true if it cannot be understood (e.g. it's a switch dispatch or isn't
438 /// implemented for a target). Upon success, this returns false and returns
439 /// with the following information in various cases:
441 /// 1. If this block ends with no branches (it just falls through to its succ)
442 /// just return false, leaving TBB/FBB null.
443 /// 2. If this block ends with only an unconditional branch, it sets TBB to be
444 /// the destination block.
445 /// 3. If this block ends with an conditional branch and it falls through to
446 /// an successor block, it sets TBB to be the branch destination block and a
447 /// list of operands that evaluate the condition. These
448 /// operands can be passed to other TargetInstrInfo methods to create new
450 /// 4. If this block ends with an conditional branch and an unconditional
451 /// block, it returns the 'true' destination in TBB, the 'false' destination
452 /// in FBB, and a list of operands that evaluate the condition. These
453 /// operands can be passed to other TargetInstrInfo methods to create new
456 /// Note that RemoveBranch and InsertBranch must be implemented to support
457 /// cases where this method returns success.
459 virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
460 MachineBasicBlock *&FBB,
461 std::vector<MachineOperand> &Cond) const {
465 /// RemoveBranch - Remove the branching code at the end of the specific MBB.
466 /// this is only invoked in cases where AnalyzeBranch returns success. It
467 /// returns the number of instructions that were removed.
468 virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const {
469 assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!");
473 /// InsertBranch - Insert a branch into the end of the specified
474 /// MachineBasicBlock. This operands to this method are the same as those
475 /// returned by AnalyzeBranch. This is invoked in cases where AnalyzeBranch
476 /// returns success and when an unconditional branch (TBB is non-null, FBB is
477 /// null, Cond is empty) needs to be inserted. It returns the number of
478 /// instructions inserted.
479 virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
480 MachineBasicBlock *FBB,
481 const std::vector<MachineOperand> &Cond) const {
482 assert(0 && "Target didn't implement TargetInstrInfo::InsertBranch!");
486 /// copyRegToReg - Add a copy between a pair of registers
487 virtual void copyRegToReg(MachineBasicBlock &MBB,
488 MachineBasicBlock::iterator MI,
489 unsigned DestReg, unsigned SrcReg,
490 const TargetRegisterClass *DestRC,
491 const TargetRegisterClass *SrcRC) const {
492 assert(0 && "Target didn't implement TargetInstrInfo::copyRegToReg!");
495 virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
496 MachineBasicBlock::iterator MI,
497 unsigned SrcReg, bool isKill, int FrameIndex,
498 const TargetRegisterClass *RC) const {
499 assert(0 && "Target didn't implement TargetInstrInfo::storeRegToStackSlot!");
502 virtual void storeRegToAddr(MachineFunction &MF, unsigned SrcReg, bool isKill,
503 SmallVectorImpl<MachineOperand> &Addr,
504 const TargetRegisterClass *RC,
505 SmallVectorImpl<MachineInstr*> &NewMIs) const {
506 assert(0 && "Target didn't implement TargetInstrInfo::storeRegToAddr!");
509 virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
510 MachineBasicBlock::iterator MI,
511 unsigned DestReg, int FrameIndex,
512 const TargetRegisterClass *RC) const {
513 assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromStackSlot!");
516 virtual void loadRegFromAddr(MachineFunction &MF, unsigned DestReg,
517 SmallVectorImpl<MachineOperand> &Addr,
518 const TargetRegisterClass *RC,
519 SmallVectorImpl<MachineInstr*> &NewMIs) const {
520 assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromAddr!");
523 /// spillCalleeSavedRegisters - Issues instruction(s) to spill all callee
524 /// saved registers and returns true if it isn't possible / profitable to do
525 /// so by issuing a series of store instructions via
526 /// storeRegToStackSlot(). Returns false otherwise.
527 virtual bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
528 MachineBasicBlock::iterator MI,
529 const std::vector<CalleeSavedInfo> &CSI) const {
533 /// restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee
534 /// saved registers and returns true if it isn't possible / profitable to do
535 /// so by issuing a series of load instructions via loadRegToStackSlot().
536 /// Returns false otherwise.
537 virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
538 MachineBasicBlock::iterator MI,
539 const std::vector<CalleeSavedInfo> &CSI) const {
543 /// BlockHasNoFallThrough - Return true if the specified block does not
544 /// fall-through into its successor block. This is primarily used when a
545 /// branch is unanalyzable. It is useful for things like unconditional
546 /// indirect branches (jump tables).
547 virtual bool BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
551 /// ReverseBranchCondition - Reverses the branch condition of the specified
552 /// condition list, returning false on success and true if it cannot be
554 virtual bool ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
558 /// insertNoop - Insert a noop into the instruction stream at the specified
560 virtual void insertNoop(MachineBasicBlock &MBB,
561 MachineBasicBlock::iterator MI) const {
562 assert(0 && "Target didn't implement insertNoop!");
566 /// isPredicated - Returns true if the instruction is already predicated.
568 virtual bool isPredicated(const MachineInstr *MI) const {
572 /// isUnpredicatedTerminator - Returns true if the instruction is a
573 /// terminator instruction that has not been predicated.
574 virtual bool isUnpredicatedTerminator(const MachineInstr *MI) const;
576 /// PredicateInstruction - Convert the instruction into a predicated
577 /// instruction. It returns true if the operation was successful.
579 bool PredicateInstruction(MachineInstr *MI,
580 const std::vector<MachineOperand> &Pred) const = 0;
582 /// SubsumesPredicate - Returns true if the first specified predicate
583 /// subsumes the second, e.g. GE subsumes GT.
585 bool SubsumesPredicate(const std::vector<MachineOperand> &Pred1,
586 const std::vector<MachineOperand> &Pred2) const {
590 /// DefinesPredicate - If the specified instruction defines any predicate
591 /// or condition code register(s) used for predication, returns true as well
592 /// as the definition predicate(s) by reference.
593 virtual bool DefinesPredicate(MachineInstr *MI,
594 std::vector<MachineOperand> &Pred) const {
598 /// getPointerRegClass - Returns a TargetRegisterClass used for pointer
600 virtual const TargetRegisterClass *getPointerRegClass() const {
601 assert(0 && "Target didn't implement getPointerRegClass!");
603 return 0; // Must return a value in order to compile with VS 2005
607 /// TargetInstrInfoImpl - This is the default implementation of
608 /// TargetInstrInfo, which just provides a couple of default implementations
609 /// for various methods. This separated out because it is implemented in
610 /// libcodegen, not in libtarget.
611 class TargetInstrInfoImpl : public TargetInstrInfo {
613 TargetInstrInfoImpl(const TargetInstrDescriptor *desc, unsigned NumOpcodes)
614 : TargetInstrInfo(desc, NumOpcodes) {}
616 virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
617 virtual bool PredicateInstruction(MachineInstr *MI,
618 const std::vector<MachineOperand> &Pred) const;
622 } // End llvm namespace