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1 //===-- Instruction.cpp - Implement the Instruction class -----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the Instruction class for the IR library.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/Instruction.h"
15 #include "llvm/IR/CallSite.h"
16 #include "llvm/IR/Constants.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/IR/Operator.h"
20 #include "llvm/IR/Type.h"
21 using namespace llvm;
22 
Instruction(Type * ty,unsigned it,Use * Ops,unsigned NumOps,Instruction * InsertBefore)23 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
24                          Instruction *InsertBefore)
25   : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(nullptr) {
26 
27   // If requested, insert this instruction into a basic block...
28   if (InsertBefore) {
29     BasicBlock *BB = InsertBefore->getParent();
30     assert(BB && "Instruction to insert before is not in a basic block!");
31     BB->getInstList().insert(InsertBefore->getIterator(), this);
32   }
33 }
34 
Instruction(Type * ty,unsigned it,Use * Ops,unsigned NumOps,BasicBlock * InsertAtEnd)35 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
36                          BasicBlock *InsertAtEnd)
37   : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(nullptr) {
38 
39   // append this instruction into the basic block
40   assert(InsertAtEnd && "Basic block to append to may not be NULL!");
41   InsertAtEnd->getInstList().push_back(this);
42 }
43 
44 
45 // Out of line virtual method, so the vtable, etc has a home.
~Instruction()46 Instruction::~Instruction() {
47   assert(!Parent && "Instruction still linked in the program!");
48   if (hasMetadataHashEntry())
49     clearMetadataHashEntries();
50 }
51 
52 
setParent(BasicBlock * P)53 void Instruction::setParent(BasicBlock *P) {
54   Parent = P;
55 }
56 
getModule() const57 const Module *Instruction::getModule() const {
58   return getParent()->getModule();
59 }
60 
getModule()61 Module *Instruction::getModule() {
62   return getParent()->getModule();
63 }
64 
getFunction()65 Function *Instruction::getFunction() { return getParent()->getParent(); }
66 
getFunction() const67 const Function *Instruction::getFunction() const {
68   return getParent()->getParent();
69 }
70 
removeFromParent()71 void Instruction::removeFromParent() {
72   getParent()->getInstList().remove(getIterator());
73 }
74 
eraseFromParent()75 iplist<Instruction>::iterator Instruction::eraseFromParent() {
76   return getParent()->getInstList().erase(getIterator());
77 }
78 
79 /// Insert an unlinked instruction into a basic block immediately before the
80 /// specified instruction.
insertBefore(Instruction * InsertPos)81 void Instruction::insertBefore(Instruction *InsertPos) {
82   InsertPos->getParent()->getInstList().insert(InsertPos->getIterator(), this);
83 }
84 
85 /// Insert an unlinked instruction into a basic block immediately after the
86 /// specified instruction.
insertAfter(Instruction * InsertPos)87 void Instruction::insertAfter(Instruction *InsertPos) {
88   InsertPos->getParent()->getInstList().insertAfter(InsertPos->getIterator(),
89                                                     this);
90 }
91 
92 /// Unlink this instruction from its current basic block and insert it into the
93 /// basic block that MovePos lives in, right before MovePos.
moveBefore(Instruction * MovePos)94 void Instruction::moveBefore(Instruction *MovePos) {
95   MovePos->getParent()->getInstList().splice(
96       MovePos->getIterator(), getParent()->getInstList(), getIterator());
97 }
98 
setHasNoUnsignedWrap(bool b)99 void Instruction::setHasNoUnsignedWrap(bool b) {
100   cast<OverflowingBinaryOperator>(this)->setHasNoUnsignedWrap(b);
101 }
102 
setHasNoSignedWrap(bool b)103 void Instruction::setHasNoSignedWrap(bool b) {
104   cast<OverflowingBinaryOperator>(this)->setHasNoSignedWrap(b);
105 }
106 
setIsExact(bool b)107 void Instruction::setIsExact(bool b) {
108   cast<PossiblyExactOperator>(this)->setIsExact(b);
109 }
110 
hasNoUnsignedWrap() const111 bool Instruction::hasNoUnsignedWrap() const {
112   return cast<OverflowingBinaryOperator>(this)->hasNoUnsignedWrap();
113 }
114 
hasNoSignedWrap() const115 bool Instruction::hasNoSignedWrap() const {
116   return cast<OverflowingBinaryOperator>(this)->hasNoSignedWrap();
117 }
118 
isExact() const119 bool Instruction::isExact() const {
120   return cast<PossiblyExactOperator>(this)->isExact();
121 }
122 
123 /// Set or clear the unsafe-algebra flag on this instruction, which must be an
124 /// operator which supports this flag. See LangRef.html for the meaning of this
125 /// flag.
setHasUnsafeAlgebra(bool B)126 void Instruction::setHasUnsafeAlgebra(bool B) {
127   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
128   cast<FPMathOperator>(this)->setHasUnsafeAlgebra(B);
129 }
130 
131 /// Set or clear the NoNaNs flag on this instruction, which must be an operator
132 /// which supports this flag. See LangRef.html for the meaning of this flag.
setHasNoNaNs(bool B)133 void Instruction::setHasNoNaNs(bool B) {
134   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
135   cast<FPMathOperator>(this)->setHasNoNaNs(B);
136 }
137 
138 /// Set or clear the no-infs flag on this instruction, which must be an operator
139 /// which supports this flag. See LangRef.html for the meaning of this flag.
setHasNoInfs(bool B)140 void Instruction::setHasNoInfs(bool B) {
141   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
142   cast<FPMathOperator>(this)->setHasNoInfs(B);
143 }
144 
145 /// Set or clear the no-signed-zeros flag on this instruction, which must be an
146 /// operator which supports this flag. See LangRef.html for the meaning of this
147 /// flag.
setHasNoSignedZeros(bool B)148 void Instruction::setHasNoSignedZeros(bool B) {
149   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
150   cast<FPMathOperator>(this)->setHasNoSignedZeros(B);
151 }
152 
153 /// Set or clear the allow-reciprocal flag on this instruction, which must be an
154 /// operator which supports this flag. See LangRef.html for the meaning of this
155 /// flag.
setHasAllowReciprocal(bool B)156 void Instruction::setHasAllowReciprocal(bool B) {
157   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
158   cast<FPMathOperator>(this)->setHasAllowReciprocal(B);
159 }
160 
161 /// Convenience function for setting all the fast-math flags on this
162 /// instruction, which must be an operator which supports these flags. See
163 /// LangRef.html for the meaning of these flats.
setFastMathFlags(FastMathFlags FMF)164 void Instruction::setFastMathFlags(FastMathFlags FMF) {
165   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
166   cast<FPMathOperator>(this)->setFastMathFlags(FMF);
167 }
168 
copyFastMathFlags(FastMathFlags FMF)169 void Instruction::copyFastMathFlags(FastMathFlags FMF) {
170   assert(isa<FPMathOperator>(this) && "copying fast-math flag on invalid op");
171   cast<FPMathOperator>(this)->copyFastMathFlags(FMF);
172 }
173 
174 /// Determine whether the unsafe-algebra flag is set.
hasUnsafeAlgebra() const175 bool Instruction::hasUnsafeAlgebra() const {
176   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
177   return cast<FPMathOperator>(this)->hasUnsafeAlgebra();
178 }
179 
180 /// Determine whether the no-NaNs flag is set.
hasNoNaNs() const181 bool Instruction::hasNoNaNs() const {
182   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
183   return cast<FPMathOperator>(this)->hasNoNaNs();
184 }
185 
186 /// Determine whether the no-infs flag is set.
hasNoInfs() const187 bool Instruction::hasNoInfs() const {
188   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
189   return cast<FPMathOperator>(this)->hasNoInfs();
190 }
191 
192 /// Determine whether the no-signed-zeros flag is set.
hasNoSignedZeros() const193 bool Instruction::hasNoSignedZeros() const {
194   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
195   return cast<FPMathOperator>(this)->hasNoSignedZeros();
196 }
197 
198 /// Determine whether the allow-reciprocal flag is set.
hasAllowReciprocal() const199 bool Instruction::hasAllowReciprocal() const {
200   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
201   return cast<FPMathOperator>(this)->hasAllowReciprocal();
202 }
203 
204 /// Convenience function for getting all the fast-math flags, which must be an
205 /// operator which supports these flags. See LangRef.html for the meaning of
206 /// these flags.
getFastMathFlags() const207 FastMathFlags Instruction::getFastMathFlags() const {
208   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
209   return cast<FPMathOperator>(this)->getFastMathFlags();
210 }
211 
212 /// Copy I's fast-math flags
copyFastMathFlags(const Instruction * I)213 void Instruction::copyFastMathFlags(const Instruction *I) {
214   copyFastMathFlags(I->getFastMathFlags());
215 }
216 
copyIRFlags(const Value * V)217 void Instruction::copyIRFlags(const Value *V) {
218   // Copy the wrapping flags.
219   if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
220     if (isa<OverflowingBinaryOperator>(this)) {
221       setHasNoSignedWrap(OB->hasNoSignedWrap());
222       setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
223     }
224   }
225 
226   // Copy the exact flag.
227   if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
228     if (isa<PossiblyExactOperator>(this))
229       setIsExact(PE->isExact());
230 
231   // Copy the fast-math flags.
232   if (auto *FP = dyn_cast<FPMathOperator>(V))
233     if (isa<FPMathOperator>(this))
234       copyFastMathFlags(FP->getFastMathFlags());
235 }
236 
andIRFlags(const Value * V)237 void Instruction::andIRFlags(const Value *V) {
238   if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
239     if (isa<OverflowingBinaryOperator>(this)) {
240       setHasNoSignedWrap(hasNoSignedWrap() & OB->hasNoSignedWrap());
241       setHasNoUnsignedWrap(hasNoUnsignedWrap() & OB->hasNoUnsignedWrap());
242     }
243   }
244 
245   if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
246     if (isa<PossiblyExactOperator>(this))
247       setIsExact(isExact() & PE->isExact());
248 
249   if (auto *FP = dyn_cast<FPMathOperator>(V)) {
250     if (isa<FPMathOperator>(this)) {
251       FastMathFlags FM = getFastMathFlags();
252       FM &= FP->getFastMathFlags();
253       copyFastMathFlags(FM);
254     }
255   }
256 }
257 
getOpcodeName(unsigned OpCode)258 const char *Instruction::getOpcodeName(unsigned OpCode) {
259   switch (OpCode) {
260   // Terminators
261   case Ret:    return "ret";
262   case Br:     return "br";
263   case Switch: return "switch";
264   case IndirectBr: return "indirectbr";
265   case Invoke: return "invoke";
266   case Resume: return "resume";
267   case Unreachable: return "unreachable";
268   case CleanupRet: return "cleanupret";
269   case CatchRet: return "catchret";
270   case CatchPad: return "catchpad";
271   case CatchSwitch: return "catchswitch";
272 
273   // Standard binary operators...
274   case Add: return "add";
275   case FAdd: return "fadd";
276   case Sub: return "sub";
277   case FSub: return "fsub";
278   case Mul: return "mul";
279   case FMul: return "fmul";
280   case UDiv: return "udiv";
281   case SDiv: return "sdiv";
282   case FDiv: return "fdiv";
283   case URem: return "urem";
284   case SRem: return "srem";
285   case FRem: return "frem";
286 
287   // Logical operators...
288   case And: return "and";
289   case Or : return "or";
290   case Xor: return "xor";
291 
292   // Memory instructions...
293   case Alloca:        return "alloca";
294   case Load:          return "load";
295   case Store:         return "store";
296   case AtomicCmpXchg: return "cmpxchg";
297   case AtomicRMW:     return "atomicrmw";
298   case Fence:         return "fence";
299   case GetElementPtr: return "getelementptr";
300 
301   // Convert instructions...
302   case Trunc:         return "trunc";
303   case ZExt:          return "zext";
304   case SExt:          return "sext";
305   case FPTrunc:       return "fptrunc";
306   case FPExt:         return "fpext";
307   case FPToUI:        return "fptoui";
308   case FPToSI:        return "fptosi";
309   case UIToFP:        return "uitofp";
310   case SIToFP:        return "sitofp";
311   case IntToPtr:      return "inttoptr";
312   case PtrToInt:      return "ptrtoint";
313   case BitCast:       return "bitcast";
314   case AddrSpaceCast: return "addrspacecast";
315 
316   // Other instructions...
317   case ICmp:           return "icmp";
318   case FCmp:           return "fcmp";
319   case PHI:            return "phi";
320   case Select:         return "select";
321   case Call:           return "call";
322   case Shl:            return "shl";
323   case LShr:           return "lshr";
324   case AShr:           return "ashr";
325   case VAArg:          return "va_arg";
326   case ExtractElement: return "extractelement";
327   case InsertElement:  return "insertelement";
328   case ShuffleVector:  return "shufflevector";
329   case ExtractValue:   return "extractvalue";
330   case InsertValue:    return "insertvalue";
331   case LandingPad:     return "landingpad";
332   case CleanupPad:     return "cleanuppad";
333 
334   default: return "<Invalid operator> ";
335   }
336 }
337 
338 /// Return true if both instructions have the same special state This must be
339 /// kept in sync with FunctionComparator::cmpOperations in
340 /// lib/Transforms/IPO/MergeFunctions.cpp.
haveSameSpecialState(const Instruction * I1,const Instruction * I2,bool IgnoreAlignment=false)341 static bool haveSameSpecialState(const Instruction *I1, const Instruction *I2,
342                                  bool IgnoreAlignment = false) {
343   assert(I1->getOpcode() == I2->getOpcode() &&
344          "Can not compare special state of different instructions");
345 
346   if (const AllocaInst *AI = dyn_cast<AllocaInst>(I1))
347     return AI->getAllocatedType() == cast<AllocaInst>(I2)->getAllocatedType() &&
348            (AI->getAlignment() == cast<AllocaInst>(I2)->getAlignment() ||
349             IgnoreAlignment);
350   if (const LoadInst *LI = dyn_cast<LoadInst>(I1))
351     return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() &&
352            (LI->getAlignment() == cast<LoadInst>(I2)->getAlignment() ||
353             IgnoreAlignment) &&
354            LI->getOrdering() == cast<LoadInst>(I2)->getOrdering() &&
355            LI->getSynchScope() == cast<LoadInst>(I2)->getSynchScope();
356   if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
357     return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
358            (SI->getAlignment() == cast<StoreInst>(I2)->getAlignment() ||
359             IgnoreAlignment) &&
360            SI->getOrdering() == cast<StoreInst>(I2)->getOrdering() &&
361            SI->getSynchScope() == cast<StoreInst>(I2)->getSynchScope();
362   if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
363     return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
364   if (const CallInst *CI = dyn_cast<CallInst>(I1))
365     return CI->isTailCall() == cast<CallInst>(I2)->isTailCall() &&
366            CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() &&
367            CI->getAttributes() == cast<CallInst>(I2)->getAttributes() &&
368            CI->hasIdenticalOperandBundleSchema(*cast<CallInst>(I2));
369   if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
370     return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
371            CI->getAttributes() == cast<InvokeInst>(I2)->getAttributes() &&
372            CI->hasIdenticalOperandBundleSchema(*cast<InvokeInst>(I2));
373   if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1))
374     return IVI->getIndices() == cast<InsertValueInst>(I2)->getIndices();
375   if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1))
376     return EVI->getIndices() == cast<ExtractValueInst>(I2)->getIndices();
377   if (const FenceInst *FI = dyn_cast<FenceInst>(I1))
378     return FI->getOrdering() == cast<FenceInst>(I2)->getOrdering() &&
379            FI->getSynchScope() == cast<FenceInst>(I2)->getSynchScope();
380   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I1))
381     return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I2)->isVolatile() &&
382            CXI->isWeak() == cast<AtomicCmpXchgInst>(I2)->isWeak() &&
383            CXI->getSuccessOrdering() ==
384                cast<AtomicCmpXchgInst>(I2)->getSuccessOrdering() &&
385            CXI->getFailureOrdering() ==
386                cast<AtomicCmpXchgInst>(I2)->getFailureOrdering() &&
387            CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I2)->getSynchScope();
388   if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I1))
389     return RMWI->getOperation() == cast<AtomicRMWInst>(I2)->getOperation() &&
390            RMWI->isVolatile() == cast<AtomicRMWInst>(I2)->isVolatile() &&
391            RMWI->getOrdering() == cast<AtomicRMWInst>(I2)->getOrdering() &&
392            RMWI->getSynchScope() == cast<AtomicRMWInst>(I2)->getSynchScope();
393 
394   return true;
395 }
396 
397 /// isIdenticalTo - Return true if the specified instruction is exactly
398 /// identical to the current one.  This means that all operands match and any
399 /// extra information (e.g. load is volatile) agree.
isIdenticalTo(const Instruction * I) const400 bool Instruction::isIdenticalTo(const Instruction *I) const {
401   return isIdenticalToWhenDefined(I) &&
402          SubclassOptionalData == I->SubclassOptionalData;
403 }
404 
405 /// isIdenticalToWhenDefined - This is like isIdenticalTo, except that it
406 /// ignores the SubclassOptionalData flags, which specify conditions
407 /// under which the instruction's result is undefined.
isIdenticalToWhenDefined(const Instruction * I) const408 bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const {
409   if (getOpcode() != I->getOpcode() ||
410       getNumOperands() != I->getNumOperands() ||
411       getType() != I->getType())
412     return false;
413 
414   // If both instructions have no operands, they are identical.
415   if (getNumOperands() == 0 && I->getNumOperands() == 0)
416     return haveSameSpecialState(this, I);
417 
418   // We have two instructions of identical opcode and #operands.  Check to see
419   // if all operands are the same.
420   if (!std::equal(op_begin(), op_end(), I->op_begin()))
421     return false;
422 
423   if (const PHINode *thisPHI = dyn_cast<PHINode>(this)) {
424     const PHINode *otherPHI = cast<PHINode>(I);
425     return std::equal(thisPHI->block_begin(), thisPHI->block_end(),
426                       otherPHI->block_begin());
427   }
428 
429   return haveSameSpecialState(this, I);
430 }
431 
432 // Keep this in sync with FunctionComparator::cmpOperations in
433 // lib/Transforms/IPO/MergeFunctions.cpp.
isSameOperationAs(const Instruction * I,unsigned flags) const434 bool Instruction::isSameOperationAs(const Instruction *I,
435                                     unsigned flags) const {
436   bool IgnoreAlignment = flags & CompareIgnoringAlignment;
437   bool UseScalarTypes  = flags & CompareUsingScalarTypes;
438 
439   if (getOpcode() != I->getOpcode() ||
440       getNumOperands() != I->getNumOperands() ||
441       (UseScalarTypes ?
442        getType()->getScalarType() != I->getType()->getScalarType() :
443        getType() != I->getType()))
444     return false;
445 
446   // We have two instructions of identical opcode and #operands.  Check to see
447   // if all operands are the same type
448   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
449     if (UseScalarTypes ?
450         getOperand(i)->getType()->getScalarType() !=
451           I->getOperand(i)->getType()->getScalarType() :
452         getOperand(i)->getType() != I->getOperand(i)->getType())
453       return false;
454 
455   return haveSameSpecialState(this, I, IgnoreAlignment);
456 }
457 
458 /// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
459 /// specified block.  Note that PHI nodes are considered to evaluate their
460 /// operands in the corresponding predecessor block.
isUsedOutsideOfBlock(const BasicBlock * BB) const461 bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
462   for (const Use &U : uses()) {
463     // PHI nodes uses values in the corresponding predecessor block.  For other
464     // instructions, just check to see whether the parent of the use matches up.
465     const Instruction *I = cast<Instruction>(U.getUser());
466     const PHINode *PN = dyn_cast<PHINode>(I);
467     if (!PN) {
468       if (I->getParent() != BB)
469         return true;
470       continue;
471     }
472 
473     if (PN->getIncomingBlock(U) != BB)
474       return true;
475   }
476   return false;
477 }
478 
479 /// mayReadFromMemory - Return true if this instruction may read memory.
480 ///
mayReadFromMemory() const481 bool Instruction::mayReadFromMemory() const {
482   switch (getOpcode()) {
483   default: return false;
484   case Instruction::VAArg:
485   case Instruction::Load:
486   case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
487   case Instruction::AtomicCmpXchg:
488   case Instruction::AtomicRMW:
489   case Instruction::CatchPad:
490   case Instruction::CatchRet:
491     return true;
492   case Instruction::Call:
493     return !cast<CallInst>(this)->doesNotAccessMemory();
494   case Instruction::Invoke:
495     return !cast<InvokeInst>(this)->doesNotAccessMemory();
496   case Instruction::Store:
497     return !cast<StoreInst>(this)->isUnordered();
498   }
499 }
500 
501 /// mayWriteToMemory - Return true if this instruction may modify memory.
502 ///
mayWriteToMemory() const503 bool Instruction::mayWriteToMemory() const {
504   switch (getOpcode()) {
505   default: return false;
506   case Instruction::Fence: // FIXME: refine definition of mayWriteToMemory
507   case Instruction::Store:
508   case Instruction::VAArg:
509   case Instruction::AtomicCmpXchg:
510   case Instruction::AtomicRMW:
511   case Instruction::CatchPad:
512   case Instruction::CatchRet:
513     return true;
514   case Instruction::Call:
515     return !cast<CallInst>(this)->onlyReadsMemory();
516   case Instruction::Invoke:
517     return !cast<InvokeInst>(this)->onlyReadsMemory();
518   case Instruction::Load:
519     return !cast<LoadInst>(this)->isUnordered();
520   }
521 }
522 
isAtomic() const523 bool Instruction::isAtomic() const {
524   switch (getOpcode()) {
525   default:
526     return false;
527   case Instruction::AtomicCmpXchg:
528   case Instruction::AtomicRMW:
529   case Instruction::Fence:
530     return true;
531   case Instruction::Load:
532     return cast<LoadInst>(this)->getOrdering() != AtomicOrdering::NotAtomic;
533   case Instruction::Store:
534     return cast<StoreInst>(this)->getOrdering() != AtomicOrdering::NotAtomic;
535   }
536 }
537 
mayThrow() const538 bool Instruction::mayThrow() const {
539   if (const CallInst *CI = dyn_cast<CallInst>(this))
540     return !CI->doesNotThrow();
541   if (const auto *CRI = dyn_cast<CleanupReturnInst>(this))
542     return CRI->unwindsToCaller();
543   if (const auto *CatchSwitch = dyn_cast<CatchSwitchInst>(this))
544     return CatchSwitch->unwindsToCaller();
545   return isa<ResumeInst>(this);
546 }
547 
548 /// isAssociative - Return true if the instruction is associative:
549 ///
550 ///   Associative operators satisfy:  x op (y op z) === (x op y) op z
551 ///
552 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative.
553 ///
isAssociative(unsigned Opcode)554 bool Instruction::isAssociative(unsigned Opcode) {
555   return Opcode == And || Opcode == Or || Opcode == Xor ||
556          Opcode == Add || Opcode == Mul;
557 }
558 
isAssociative() const559 bool Instruction::isAssociative() const {
560   unsigned Opcode = getOpcode();
561   if (isAssociative(Opcode))
562     return true;
563 
564   switch (Opcode) {
565   case FMul:
566   case FAdd:
567     return cast<FPMathOperator>(this)->hasUnsafeAlgebra();
568   default:
569     return false;
570   }
571 }
572 
573 /// isCommutative - Return true if the instruction is commutative:
574 ///
575 ///   Commutative operators satisfy: (x op y) === (y op x)
576 ///
577 /// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
578 /// applied to any type.
579 ///
isCommutative(unsigned op)580 bool Instruction::isCommutative(unsigned op) {
581   switch (op) {
582   case Add:
583   case FAdd:
584   case Mul:
585   case FMul:
586   case And:
587   case Or:
588   case Xor:
589     return true;
590   default:
591     return false;
592   }
593 }
594 
595 /// isIdempotent - Return true if the instruction is idempotent:
596 ///
597 ///   Idempotent operators satisfy:  x op x === x
598 ///
599 /// In LLVM, the And and Or operators are idempotent.
600 ///
isIdempotent(unsigned Opcode)601 bool Instruction::isIdempotent(unsigned Opcode) {
602   return Opcode == And || Opcode == Or;
603 }
604 
605 /// isNilpotent - Return true if the instruction is nilpotent:
606 ///
607 ///   Nilpotent operators satisfy:  x op x === Id,
608 ///
609 ///   where Id is the identity for the operator, i.e. a constant such that
610 ///     x op Id === x and Id op x === x for all x.
611 ///
612 /// In LLVM, the Xor operator is nilpotent.
613 ///
isNilpotent(unsigned Opcode)614 bool Instruction::isNilpotent(unsigned Opcode) {
615   return Opcode == Xor;
616 }
617 
cloneImpl() const618 Instruction *Instruction::cloneImpl() const {
619   llvm_unreachable("Subclass of Instruction failed to implement cloneImpl");
620 }
621 
clone() const622 Instruction *Instruction::clone() const {
623   Instruction *New = nullptr;
624   switch (getOpcode()) {
625   default:
626     llvm_unreachable("Unhandled Opcode.");
627 #define HANDLE_INST(num, opc, clas)                                            \
628   case Instruction::opc:                                                       \
629     New = cast<clas>(this)->cloneImpl();                                       \
630     break;
631 #include "llvm/IR/Instruction.def"
632 #undef HANDLE_INST
633   }
634 
635   New->SubclassOptionalData = SubclassOptionalData;
636   if (!hasMetadata())
637     return New;
638 
639   // Otherwise, enumerate and copy over metadata from the old instruction to the
640   // new one.
641   SmallVector<std::pair<unsigned, MDNode *>, 4> TheMDs;
642   getAllMetadataOtherThanDebugLoc(TheMDs);
643   for (const auto &MD : TheMDs)
644     New->setMetadata(MD.first, MD.second);
645 
646   New->setDebugLoc(getDebugLoc());
647   return New;
648 }
649