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/ADT/DenseSet.h"
16 #include "llvm/IR/Constants.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/IR/MDBuilder.h"
19 #include "llvm/IR/Operator.h"
20 #include "llvm/IR/Type.h"
21 using namespace llvm;
22 
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 
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 Instruction::~Instruction() {
45   assert(!Parent && "Instruction still linked in the program!");
46   if (hasMetadataHashEntry())
47     clearMetadataHashEntries();
48 }
49 
50 
51 void Instruction::setParent(BasicBlock *P) {
52   Parent = P;
53 }
54 
55 const Module *Instruction::getModule() const {
56   return getParent()->getModule();
57 }
58 
59 const Function *Instruction::getFunction() const {
60   return getParent()->getParent();
61 }
62 
63 void Instruction::removeFromParent() {
64   getParent()->getInstList().remove(getIterator());
65 }
66 
67 iplist<Instruction>::iterator Instruction::eraseFromParent() {
68   return getParent()->getInstList().erase(getIterator());
69 }
70 
71 /// Insert an unlinked instruction into a basic block immediately before the
72 /// specified instruction.
73 void Instruction::insertBefore(Instruction *InsertPos) {
74   InsertPos->getParent()->getInstList().insert(InsertPos->getIterator(), this);
75 }
76 
77 /// Insert an unlinked instruction into a basic block immediately after the
78 /// specified instruction.
79 void Instruction::insertAfter(Instruction *InsertPos) {
80   InsertPos->getParent()->getInstList().insertAfter(InsertPos->getIterator(),
81                                                     this);
82 }
83 
84 /// Unlink this instruction from its current basic block and insert it into the
85 /// basic block that MovePos lives in, right before MovePos.
86 void Instruction::moveBefore(Instruction *MovePos) {
87   moveBefore(*MovePos->getParent(), MovePos->getIterator());
88 }
89 
90 void Instruction::moveAfter(Instruction *MovePos) {
91   moveBefore(*MovePos->getParent(), ++MovePos->getIterator());
92 }
93 
94 void Instruction::moveBefore(BasicBlock &BB,
95                              SymbolTableList<Instruction>::iterator I) {
96   assert(I == BB.end() || I->getParent() == &BB);
97   BB.getInstList().splice(I, getParent()->getInstList(), getIterator());
98 }
99 
100 void Instruction::setHasNoUnsignedWrap(bool b) {
101   cast<OverflowingBinaryOperator>(this)->setHasNoUnsignedWrap(b);
102 }
103 
104 void Instruction::setHasNoSignedWrap(bool b) {
105   cast<OverflowingBinaryOperator>(this)->setHasNoSignedWrap(b);
106 }
107 
108 void Instruction::setIsExact(bool b) {
109   cast<PossiblyExactOperator>(this)->setIsExact(b);
110 }
111 
112 bool Instruction::hasNoUnsignedWrap() const {
113   return cast<OverflowingBinaryOperator>(this)->hasNoUnsignedWrap();
114 }
115 
116 bool Instruction::hasNoSignedWrap() const {
117   return cast<OverflowingBinaryOperator>(this)->hasNoSignedWrap();
118 }
119 
120 void Instruction::dropPoisonGeneratingFlags() {
121   switch (getOpcode()) {
122   case Instruction::Add:
123   case Instruction::Sub:
124   case Instruction::Mul:
125   case Instruction::Shl:
126     cast<OverflowingBinaryOperator>(this)->setHasNoUnsignedWrap(false);
127     cast<OverflowingBinaryOperator>(this)->setHasNoSignedWrap(false);
128     break;
129 
130   case Instruction::UDiv:
131   case Instruction::SDiv:
132   case Instruction::AShr:
133   case Instruction::LShr:
134     cast<PossiblyExactOperator>(this)->setIsExact(false);
135     break;
136 
137   case Instruction::GetElementPtr:
138     cast<GetElementPtrInst>(this)->setIsInBounds(false);
139     break;
140   }
141 }
142 
143 bool Instruction::isExact() const {
144   return cast<PossiblyExactOperator>(this)->isExact();
145 }
146 
147 void Instruction::setFast(bool B) {
148   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
149   cast<FPMathOperator>(this)->setFast(B);
150 }
151 
152 void Instruction::setHasAllowReassoc(bool B) {
153   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
154   cast<FPMathOperator>(this)->setHasAllowReassoc(B);
155 }
156 
157 void Instruction::setHasNoNaNs(bool B) {
158   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
159   cast<FPMathOperator>(this)->setHasNoNaNs(B);
160 }
161 
162 void Instruction::setHasNoInfs(bool B) {
163   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
164   cast<FPMathOperator>(this)->setHasNoInfs(B);
165 }
166 
167 void Instruction::setHasNoSignedZeros(bool B) {
168   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
169   cast<FPMathOperator>(this)->setHasNoSignedZeros(B);
170 }
171 
172 void Instruction::setHasAllowReciprocal(bool B) {
173   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
174   cast<FPMathOperator>(this)->setHasAllowReciprocal(B);
175 }
176 
177 void Instruction::setHasApproxFunc(bool B) {
178   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
179   cast<FPMathOperator>(this)->setHasApproxFunc(B);
180 }
181 
182 void Instruction::setFastMathFlags(FastMathFlags FMF) {
183   assert(isa<FPMathOperator>(this) && "setting fast-math flag on invalid op");
184   cast<FPMathOperator>(this)->setFastMathFlags(FMF);
185 }
186 
187 void Instruction::copyFastMathFlags(FastMathFlags FMF) {
188   assert(isa<FPMathOperator>(this) && "copying fast-math flag on invalid op");
189   cast<FPMathOperator>(this)->copyFastMathFlags(FMF);
190 }
191 
192 bool Instruction::isFast() const {
193   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
194   return cast<FPMathOperator>(this)->isFast();
195 }
196 
197 bool Instruction::hasAllowReassoc() const {
198   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
199   return cast<FPMathOperator>(this)->hasAllowReassoc();
200 }
201 
202 bool Instruction::hasNoNaNs() const {
203   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
204   return cast<FPMathOperator>(this)->hasNoNaNs();
205 }
206 
207 bool Instruction::hasNoInfs() const {
208   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
209   return cast<FPMathOperator>(this)->hasNoInfs();
210 }
211 
212 bool Instruction::hasNoSignedZeros() const {
213   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
214   return cast<FPMathOperator>(this)->hasNoSignedZeros();
215 }
216 
217 bool Instruction::hasAllowReciprocal() const {
218   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
219   return cast<FPMathOperator>(this)->hasAllowReciprocal();
220 }
221 
222 bool Instruction::hasAllowContract() const {
223   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
224   return cast<FPMathOperator>(this)->hasAllowContract();
225 }
226 
227 bool Instruction::hasApproxFunc() const {
228   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
229   return cast<FPMathOperator>(this)->hasApproxFunc();
230 }
231 
232 FastMathFlags Instruction::getFastMathFlags() const {
233   assert(isa<FPMathOperator>(this) && "getting fast-math flag on invalid op");
234   return cast<FPMathOperator>(this)->getFastMathFlags();
235 }
236 
237 void Instruction::copyFastMathFlags(const Instruction *I) {
238   copyFastMathFlags(I->getFastMathFlags());
239 }
240 
241 void Instruction::copyIRFlags(const Value *V, bool IncludeWrapFlags) {
242   // Copy the wrapping flags.
243   if (IncludeWrapFlags && isa<OverflowingBinaryOperator>(this)) {
244     if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
245       setHasNoSignedWrap(OB->hasNoSignedWrap());
246       setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
247     }
248   }
249 
250   // Copy the exact flag.
251   if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
252     if (isa<PossiblyExactOperator>(this))
253       setIsExact(PE->isExact());
254 
255   // Copy the fast-math flags.
256   if (auto *FP = dyn_cast<FPMathOperator>(V))
257     if (isa<FPMathOperator>(this))
258       copyFastMathFlags(FP->getFastMathFlags());
259 
260   if (auto *SrcGEP = dyn_cast<GetElementPtrInst>(V))
261     if (auto *DestGEP = dyn_cast<GetElementPtrInst>(this))
262       DestGEP->setIsInBounds(SrcGEP->isInBounds() | DestGEP->isInBounds());
263 }
264 
265 void Instruction::andIRFlags(const Value *V) {
266   if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
267     if (isa<OverflowingBinaryOperator>(this)) {
268       setHasNoSignedWrap(hasNoSignedWrap() & OB->hasNoSignedWrap());
269       setHasNoUnsignedWrap(hasNoUnsignedWrap() & OB->hasNoUnsignedWrap());
270     }
271   }
272 
273   if (auto *PE = dyn_cast<PossiblyExactOperator>(V))
274     if (isa<PossiblyExactOperator>(this))
275       setIsExact(isExact() & PE->isExact());
276 
277   if (auto *FP = dyn_cast<FPMathOperator>(V)) {
278     if (isa<FPMathOperator>(this)) {
279       FastMathFlags FM = getFastMathFlags();
280       FM &= FP->getFastMathFlags();
281       copyFastMathFlags(FM);
282     }
283   }
284 
285   if (auto *SrcGEP = dyn_cast<GetElementPtrInst>(V))
286     if (auto *DestGEP = dyn_cast<GetElementPtrInst>(this))
287       DestGEP->setIsInBounds(SrcGEP->isInBounds() & DestGEP->isInBounds());
288 }
289 
290 const char *Instruction::getOpcodeName(unsigned OpCode) {
291   switch (OpCode) {
292   // Terminators
293   case Ret:    return "ret";
294   case Br:     return "br";
295   case Switch: return "switch";
296   case IndirectBr: return "indirectbr";
297   case Invoke: return "invoke";
298   case Resume: return "resume";
299   case Unreachable: return "unreachable";
300   case CleanupRet: return "cleanupret";
301   case CatchRet: return "catchret";
302   case CatchPad: return "catchpad";
303   case CatchSwitch: return "catchswitch";
304 
305   // Standard binary operators...
306   case Add: return "add";
307   case FAdd: return "fadd";
308   case Sub: return "sub";
309   case FSub: return "fsub";
310   case Mul: return "mul";
311   case FMul: return "fmul";
312   case UDiv: return "udiv";
313   case SDiv: return "sdiv";
314   case FDiv: return "fdiv";
315   case URem: return "urem";
316   case SRem: return "srem";
317   case FRem: return "frem";
318 
319   // Logical operators...
320   case And: return "and";
321   case Or : return "or";
322   case Xor: return "xor";
323 
324   // Memory instructions...
325   case Alloca:        return "alloca";
326   case Load:          return "load";
327   case Store:         return "store";
328   case AtomicCmpXchg: return "cmpxchg";
329   case AtomicRMW:     return "atomicrmw";
330   case Fence:         return "fence";
331   case GetElementPtr: return "getelementptr";
332 
333   // Convert instructions...
334   case Trunc:         return "trunc";
335   case ZExt:          return "zext";
336   case SExt:          return "sext";
337   case FPTrunc:       return "fptrunc";
338   case FPExt:         return "fpext";
339   case FPToUI:        return "fptoui";
340   case FPToSI:        return "fptosi";
341   case UIToFP:        return "uitofp";
342   case SIToFP:        return "sitofp";
343   case IntToPtr:      return "inttoptr";
344   case PtrToInt:      return "ptrtoint";
345   case BitCast:       return "bitcast";
346   case AddrSpaceCast: return "addrspacecast";
347 
348   // Other instructions...
349   case ICmp:           return "icmp";
350   case FCmp:           return "fcmp";
351   case PHI:            return "phi";
352   case Select:         return "select";
353   case Call:           return "call";
354   case Shl:            return "shl";
355   case LShr:           return "lshr";
356   case AShr:           return "ashr";
357   case VAArg:          return "va_arg";
358   case ExtractElement: return "extractelement";
359   case InsertElement:  return "insertelement";
360   case ShuffleVector:  return "shufflevector";
361   case ExtractValue:   return "extractvalue";
362   case InsertValue:    return "insertvalue";
363   case LandingPad:     return "landingpad";
364   case CleanupPad:     return "cleanuppad";
365 
366   default: return "<Invalid operator> ";
367   }
368 }
369 
370 /// Return true if both instructions have the same special state. This must be
371 /// kept in sync with FunctionComparator::cmpOperations in
372 /// lib/Transforms/IPO/MergeFunctions.cpp.
373 static bool haveSameSpecialState(const Instruction *I1, const Instruction *I2,
374                                  bool IgnoreAlignment = false) {
375   assert(I1->getOpcode() == I2->getOpcode() &&
376          "Can not compare special state of different instructions");
377 
378   if (const AllocaInst *AI = dyn_cast<AllocaInst>(I1))
379     return AI->getAllocatedType() == cast<AllocaInst>(I2)->getAllocatedType() &&
380            (AI->getAlignment() == cast<AllocaInst>(I2)->getAlignment() ||
381             IgnoreAlignment);
382   if (const LoadInst *LI = dyn_cast<LoadInst>(I1))
383     return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() &&
384            (LI->getAlignment() == cast<LoadInst>(I2)->getAlignment() ||
385             IgnoreAlignment) &&
386            LI->getOrdering() == cast<LoadInst>(I2)->getOrdering() &&
387            LI->getSyncScopeID() == cast<LoadInst>(I2)->getSyncScopeID();
388   if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
389     return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
390            (SI->getAlignment() == cast<StoreInst>(I2)->getAlignment() ||
391             IgnoreAlignment) &&
392            SI->getOrdering() == cast<StoreInst>(I2)->getOrdering() &&
393            SI->getSyncScopeID() == cast<StoreInst>(I2)->getSyncScopeID();
394   if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
395     return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
396   if (const CallInst *CI = dyn_cast<CallInst>(I1))
397     return CI->isTailCall() == cast<CallInst>(I2)->isTailCall() &&
398            CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() &&
399            CI->getAttributes() == cast<CallInst>(I2)->getAttributes() &&
400            CI->hasIdenticalOperandBundleSchema(*cast<CallInst>(I2));
401   if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
402     return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
403            CI->getAttributes() == cast<InvokeInst>(I2)->getAttributes() &&
404            CI->hasIdenticalOperandBundleSchema(*cast<InvokeInst>(I2));
405   if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1))
406     return IVI->getIndices() == cast<InsertValueInst>(I2)->getIndices();
407   if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1))
408     return EVI->getIndices() == cast<ExtractValueInst>(I2)->getIndices();
409   if (const FenceInst *FI = dyn_cast<FenceInst>(I1))
410     return FI->getOrdering() == cast<FenceInst>(I2)->getOrdering() &&
411            FI->getSyncScopeID() == cast<FenceInst>(I2)->getSyncScopeID();
412   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I1))
413     return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I2)->isVolatile() &&
414            CXI->isWeak() == cast<AtomicCmpXchgInst>(I2)->isWeak() &&
415            CXI->getSuccessOrdering() ==
416                cast<AtomicCmpXchgInst>(I2)->getSuccessOrdering() &&
417            CXI->getFailureOrdering() ==
418                cast<AtomicCmpXchgInst>(I2)->getFailureOrdering() &&
419            CXI->getSyncScopeID() ==
420                cast<AtomicCmpXchgInst>(I2)->getSyncScopeID();
421   if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I1))
422     return RMWI->getOperation() == cast<AtomicRMWInst>(I2)->getOperation() &&
423            RMWI->isVolatile() == cast<AtomicRMWInst>(I2)->isVolatile() &&
424            RMWI->getOrdering() == cast<AtomicRMWInst>(I2)->getOrdering() &&
425            RMWI->getSyncScopeID() == cast<AtomicRMWInst>(I2)->getSyncScopeID();
426 
427   return true;
428 }
429 
430 bool Instruction::isIdenticalTo(const Instruction *I) const {
431   return isIdenticalToWhenDefined(I) &&
432          SubclassOptionalData == I->SubclassOptionalData;
433 }
434 
435 bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const {
436   if (getOpcode() != I->getOpcode() ||
437       getNumOperands() != I->getNumOperands() ||
438       getType() != I->getType())
439     return false;
440 
441   // If both instructions have no operands, they are identical.
442   if (getNumOperands() == 0 && I->getNumOperands() == 0)
443     return haveSameSpecialState(this, I);
444 
445   // We have two instructions of identical opcode and #operands.  Check to see
446   // if all operands are the same.
447   if (!std::equal(op_begin(), op_end(), I->op_begin()))
448     return false;
449 
450   if (const PHINode *thisPHI = dyn_cast<PHINode>(this)) {
451     const PHINode *otherPHI = cast<PHINode>(I);
452     return std::equal(thisPHI->block_begin(), thisPHI->block_end(),
453                       otherPHI->block_begin());
454   }
455 
456   return haveSameSpecialState(this, I);
457 }
458 
459 // Keep this in sync with FunctionComparator::cmpOperations in
460 // lib/Transforms/IPO/MergeFunctions.cpp.
461 bool Instruction::isSameOperationAs(const Instruction *I,
462                                     unsigned flags) const {
463   bool IgnoreAlignment = flags & CompareIgnoringAlignment;
464   bool UseScalarTypes  = flags & CompareUsingScalarTypes;
465 
466   if (getOpcode() != I->getOpcode() ||
467       getNumOperands() != I->getNumOperands() ||
468       (UseScalarTypes ?
469        getType()->getScalarType() != I->getType()->getScalarType() :
470        getType() != I->getType()))
471     return false;
472 
473   // We have two instructions of identical opcode and #operands.  Check to see
474   // if all operands are the same type
475   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
476     if (UseScalarTypes ?
477         getOperand(i)->getType()->getScalarType() !=
478           I->getOperand(i)->getType()->getScalarType() :
479         getOperand(i)->getType() != I->getOperand(i)->getType())
480       return false;
481 
482   return haveSameSpecialState(this, I, IgnoreAlignment);
483 }
484 
485 bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
486   for (const Use &U : uses()) {
487     // PHI nodes uses values in the corresponding predecessor block.  For other
488     // instructions, just check to see whether the parent of the use matches up.
489     const Instruction *I = cast<Instruction>(U.getUser());
490     const PHINode *PN = dyn_cast<PHINode>(I);
491     if (!PN) {
492       if (I->getParent() != BB)
493         return true;
494       continue;
495     }
496 
497     if (PN->getIncomingBlock(U) != BB)
498       return true;
499   }
500   return false;
501 }
502 
503 bool Instruction::mayReadFromMemory() const {
504   switch (getOpcode()) {
505   default: return false;
506   case Instruction::VAArg:
507   case Instruction::Load:
508   case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
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)->doesNotAccessMemory();
516   case Instruction::Invoke:
517     return !cast<InvokeInst>(this)->doesNotAccessMemory();
518   case Instruction::Store:
519     return !cast<StoreInst>(this)->isUnordered();
520   }
521 }
522 
523 bool Instruction::mayWriteToMemory() const {
524   switch (getOpcode()) {
525   default: return false;
526   case Instruction::Fence: // FIXME: refine definition of mayWriteToMemory
527   case Instruction::Store:
528   case Instruction::VAArg:
529   case Instruction::AtomicCmpXchg:
530   case Instruction::AtomicRMW:
531   case Instruction::CatchPad:
532   case Instruction::CatchRet:
533     return true;
534   case Instruction::Call:
535     return !cast<CallInst>(this)->onlyReadsMemory();
536   case Instruction::Invoke:
537     return !cast<InvokeInst>(this)->onlyReadsMemory();
538   case Instruction::Load:
539     return !cast<LoadInst>(this)->isUnordered();
540   }
541 }
542 
543 bool Instruction::isAtomic() const {
544   switch (getOpcode()) {
545   default:
546     return false;
547   case Instruction::AtomicCmpXchg:
548   case Instruction::AtomicRMW:
549   case Instruction::Fence:
550     return true;
551   case Instruction::Load:
552     return cast<LoadInst>(this)->getOrdering() != AtomicOrdering::NotAtomic;
553   case Instruction::Store:
554     return cast<StoreInst>(this)->getOrdering() != AtomicOrdering::NotAtomic;
555   }
556 }
557 
558 bool Instruction::hasAtomicLoad() const {
559   assert(isAtomic());
560   switch (getOpcode()) {
561   default:
562     return false;
563   case Instruction::AtomicCmpXchg:
564   case Instruction::AtomicRMW:
565   case Instruction::Load:
566     return true;
567   }
568 }
569 
570 bool Instruction::hasAtomicStore() const {
571   assert(isAtomic());
572   switch (getOpcode()) {
573   default:
574     return false;
575   case Instruction::AtomicCmpXchg:
576   case Instruction::AtomicRMW:
577   case Instruction::Store:
578     return true;
579   }
580 }
581 
582 bool Instruction::mayThrow() const {
583   if (const CallInst *CI = dyn_cast<CallInst>(this))
584     return !CI->doesNotThrow();
585   if (const auto *CRI = dyn_cast<CleanupReturnInst>(this))
586     return CRI->unwindsToCaller();
587   if (const auto *CatchSwitch = dyn_cast<CatchSwitchInst>(this))
588     return CatchSwitch->unwindsToCaller();
589   return isa<ResumeInst>(this);
590 }
591 
592 bool Instruction::isAssociative() const {
593   unsigned Opcode = getOpcode();
594   if (isAssociative(Opcode))
595     return true;
596 
597   switch (Opcode) {
598   case FMul:
599   case FAdd:
600     return cast<FPMathOperator>(this)->isFast();
601   default:
602     return false;
603   }
604 }
605 
606 Instruction *Instruction::cloneImpl() const {
607   llvm_unreachable("Subclass of Instruction failed to implement cloneImpl");
608 }
609 
610 void Instruction::swapProfMetadata() {
611   MDNode *ProfileData = getMetadata(LLVMContext::MD_prof);
612   if (!ProfileData || ProfileData->getNumOperands() != 3 ||
613       !isa<MDString>(ProfileData->getOperand(0)))
614     return;
615 
616   MDString *MDName = cast<MDString>(ProfileData->getOperand(0));
617   if (MDName->getString() != "branch_weights")
618     return;
619 
620   // The first operand is the name. Fetch them backwards and build a new one.
621   Metadata *Ops[] = {ProfileData->getOperand(0), ProfileData->getOperand(2),
622                      ProfileData->getOperand(1)};
623   setMetadata(LLVMContext::MD_prof,
624               MDNode::get(ProfileData->getContext(), Ops));
625 }
626 
627 void Instruction::copyMetadata(const Instruction &SrcInst,
628                                ArrayRef<unsigned> WL) {
629   if (!SrcInst.hasMetadata())
630     return;
631 
632   DenseSet<unsigned> WLS;
633   for (unsigned M : WL)
634     WLS.insert(M);
635 
636   // Otherwise, enumerate and copy over metadata from the old instruction to the
637   // new one.
638   SmallVector<std::pair<unsigned, MDNode *>, 4> TheMDs;
639   SrcInst.getAllMetadataOtherThanDebugLoc(TheMDs);
640   for (const auto &MD : TheMDs) {
641     if (WL.empty() || WLS.count(MD.first))
642       setMetadata(MD.first, MD.second);
643   }
644   if (WL.empty() || WLS.count(LLVMContext::MD_dbg))
645     setDebugLoc(SrcInst.getDebugLoc());
646 }
647 
648 Instruction *Instruction::clone() const {
649   Instruction *New = nullptr;
650   switch (getOpcode()) {
651   default:
652     llvm_unreachable("Unhandled Opcode.");
653 #define HANDLE_INST(num, opc, clas)                                            \
654   case Instruction::opc:                                                       \
655     New = cast<clas>(this)->cloneImpl();                                       \
656     break;
657 #include "llvm/IR/Instruction.def"
658 #undef HANDLE_INST
659   }
660 
661   New->SubclassOptionalData = SubclassOptionalData;
662   New->copyMetadata(*this);
663   return New;
664 }
665 
666 void Instruction::updateProfWeight(uint64_t S, uint64_t T) {
667   auto *ProfileData = getMetadata(LLVMContext::MD_prof);
668   if (ProfileData == nullptr)
669     return;
670 
671   auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
672   if (!ProfDataName || (!ProfDataName->getString().equals("branch_weights") &&
673                         !ProfDataName->getString().equals("VP")))
674     return;
675 
676   MDBuilder MDB(getContext());
677   SmallVector<Metadata *, 3> Vals;
678   Vals.push_back(ProfileData->getOperand(0));
679   APInt APS(128, S), APT(128, T);
680   if (ProfDataName->getString().equals("branch_weights"))
681     for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
682       // Using APInt::div may be expensive, but most cases should fit 64 bits.
683       APInt Val(128,
684                 mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i))
685                     ->getValue()
686                     .getZExtValue());
687       Val *= APS;
688       Vals.push_back(MDB.createConstant(
689           ConstantInt::get(Type::getInt64Ty(getContext()),
690                            Val.udiv(APT).getLimitedValue())));
691     }
692   else if (ProfDataName->getString().equals("VP"))
693     for (unsigned i = 1; i < ProfileData->getNumOperands(); i += 2) {
694       // The first value is the key of the value profile, which will not change.
695       Vals.push_back(ProfileData->getOperand(i));
696       // Using APInt::div may be expensive, but most cases should fit 64 bits.
697       APInt Val(128,
698                 mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i + 1))
699                     ->getValue()
700                     .getZExtValue());
701       Val *= APS;
702       Vals.push_back(MDB.createConstant(
703           ConstantInt::get(Type::getInt64Ty(getContext()),
704                            Val.udiv(APT).getLimitedValue())));
705     }
706   setMetadata(LLVMContext::MD_prof, MDNode::get(getContext(), Vals));
707 }
708 
709 void Instruction::setProfWeight(uint64_t W) {
710   assert((isa<CallInst>(this) || isa<InvokeInst>(this)) &&
711          "Can only set weights for call and invoke instrucitons");
712   SmallVector<uint32_t, 1> Weights;
713   Weights.push_back(W);
714   MDBuilder MDB(getContext());
715   setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
716 }
717