+
+/// isIdenticalTo - Return true if the specified instruction is exactly
+/// identical to the current one. This means that all operands match and any
+/// extra information (e.g. load is volatile) agree.
+bool Instruction::isIdenticalTo(const Instruction *I) const {
+ if (getOpcode() != I->getOpcode() ||
+ getNumOperands() != I->getNumOperands() ||
+ getType() != I->getType())
+ return false;
+
+ // We have two instructions of identical opcode and #operands. Check to see
+ // if all operands are the same.
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (getOperand(i) != I->getOperand(i))
+ return false;
+
+ // Check special state that is a part of some instructions.
+ if (const LoadInst *LI = dyn_cast<LoadInst>(this))
+ return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
+ LI->getAlignment() == cast<LoadInst>(I)->getAlignment();
+ if (const StoreInst *SI = dyn_cast<StoreInst>(this))
+ return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
+ SI->getAlignment() == cast<StoreInst>(I)->getAlignment();
+ if (const CmpInst *CI = dyn_cast<CmpInst>(this))
+ return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
+ if (const CallInst *CI = dyn_cast<CallInst>(this))
+ return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
+ CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
+ CI->getAttributes().getRawPointer() ==
+ cast<CallInst>(I)->getAttributes().getRawPointer();
+ if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
+ return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
+ CI->getAttributes().getRawPointer() ==
+ cast<InvokeInst>(I)->getAttributes().getRawPointer();
+ if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) {
+ if (IVI->getNumIndices() != cast<InsertValueInst>(I)->getNumIndices())
+ return false;
+ for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
+ if (IVI->idx_begin()[i] != cast<InsertValueInst>(I)->idx_begin()[i])
+ return false;
+ return true;
+ }
+ if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) {
+ if (EVI->getNumIndices() != cast<ExtractValueInst>(I)->getNumIndices())
+ return false;
+ for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
+ if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I)->idx_begin()[i])
+ return false;
+ return true;
+ }
+
+ return true;
+}
+
+// isSameOperationAs
+// This should be kept in sync with isEquivalentOperation in
+// lib/Transforms/IPO/MergeFunctions.cpp.
+bool Instruction::isSameOperationAs(const Instruction *I) const {
+ if (getOpcode() != I->getOpcode() ||
+ getNumOperands() != I->getNumOperands() ||
+ getType() != I->getType())
+ return false;
+
+ // We have two instructions of identical opcode and #operands. Check to see
+ // if all operands are the same type
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (getOperand(i)->getType() != I->getOperand(i)->getType())
+ return false;
+
+ // Check special state that is a part of some instructions.
+ if (const LoadInst *LI = dyn_cast<LoadInst>(this))
+ return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
+ LI->getAlignment() == cast<LoadInst>(I)->getAlignment();
+ if (const StoreInst *SI = dyn_cast<StoreInst>(this))
+ return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
+ SI->getAlignment() == cast<StoreInst>(I)->getAlignment();
+ if (const CmpInst *CI = dyn_cast<CmpInst>(this))
+ return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
+ if (const CallInst *CI = dyn_cast<CallInst>(this))
+ return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
+ CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
+ CI->getAttributes().getRawPointer() ==
+ cast<CallInst>(I)->getAttributes().getRawPointer();
+ if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
+ return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
+ CI->getAttributes().getRawPointer() ==
+ cast<InvokeInst>(I)->getAttributes().getRawPointer();
+ if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) {
+ if (IVI->getNumIndices() != cast<InsertValueInst>(I)->getNumIndices())
+ return false;
+ for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
+ if (IVI->idx_begin()[i] != cast<InsertValueInst>(I)->idx_begin()[i])
+ return false;
+ return true;
+ }
+ if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) {
+ if (EVI->getNumIndices() != cast<ExtractValueInst>(I)->getNumIndices())
+ return false;
+ for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
+ if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I)->idx_begin()[i])
+ return false;
+ return true;
+ }
+
+ return true;
+}
+
+/// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
+/// specified block. Note that PHI nodes are considered to evaluate their
+/// operands in the corresponding predecessor block.
+bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
+ for (use_const_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
+ // PHI nodes uses values in the corresponding predecessor block. For other
+ // instructions, just check to see whether the parent of the use matches up.
+ const PHINode *PN = dyn_cast<PHINode>(*UI);
+ if (PN == 0) {
+ if (cast<Instruction>(*UI)->getParent() != BB)
+ return true;
+ continue;
+ }
+
+ if (PN->getIncomingBlock(UI) != BB)
+ return true;
+ }
+ return false;
+}
+
+/// mayReadFromMemory - Return true if this instruction may read memory.
+///
+bool Instruction::mayReadFromMemory() const {
+ switch (getOpcode()) {
+ default: return false;
+ case Instruction::Free:
+ case Instruction::VAArg:
+ case Instruction::Load:
+ return true;
+ case Instruction::Call:
+ return !cast<CallInst>(this)->doesNotAccessMemory();
+ case Instruction::Invoke:
+ return !cast<InvokeInst>(this)->doesNotAccessMemory();
+ case Instruction::Store:
+ return cast<StoreInst>(this)->isVolatile();
+ }
+}
+
+/// mayWriteToMemory - Return true if this instruction may modify memory.
+///
+bool Instruction::mayWriteToMemory() const {
+ switch (getOpcode()) {
+ default: return false;
+ case Instruction::Free:
+ case Instruction::Store:
+ case Instruction::VAArg:
+ return true;
+ case Instruction::Call:
+ return !cast<CallInst>(this)->onlyReadsMemory();
+ case Instruction::Invoke:
+ return !cast<InvokeInst>(this)->onlyReadsMemory();
+ case Instruction::Load:
+ return cast<LoadInst>(this)->isVolatile();
+ }
+}
+
+/// mayThrow - Return true if this instruction may throw an exception.
+///
+bool Instruction::mayThrow() const {
+ if (const CallInst *CI = dyn_cast<CallInst>(this))
+ return !CI->doesNotThrow();
+ return false;
+}
+
+/// isAssociative - Return true if the instruction is associative:
+///
+/// Associative operators satisfy: x op (y op z) === (x op y) op z
+///
+/// In LLVM, the Add, Mul, And, Or, and Xor operators are associative.
+///
+bool Instruction::isAssociative(unsigned Opcode, const Type *Ty) {
+ return Opcode == And || Opcode == Or || Opcode == Xor ||
+ Opcode == Add || Opcode == Mul;
+}
+
+/// isCommutative - Return true if the instruction is commutative:
+///
+/// Commutative operators satisfy: (x op y) === (y op x)
+///
+/// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
+/// applied to any type.
+///
+bool Instruction::isCommutative(unsigned op) {
+ switch (op) {
+ case Add:
+ case FAdd:
+ case Mul:
+ case FMul:
+ case And:
+ case Or:
+ case Xor:
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool Instruction::isSafeToSpeculativelyExecute() const {
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (Constant *C = dyn_cast<Constant>(getOperand(i)))
+ if (C->canTrap())
+ return false;
+
+ switch (getOpcode()) {
+ default:
+ return true;
+ case UDiv:
+ case URem: {
+ // x / y is undefined if y == 0, but calcuations like x / 3 are safe.
+ ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
+ return Op && !Op->isNullValue();
+ }
+ case SDiv:
+ case SRem: {
+ // x / y is undefined if y == 0, and might be undefined if y == -1,
+ // but calcuations like x / 3 are safe.
+ ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
+ return Op && !Op->isNullValue() && !Op->isAllOnesValue();
+ }
+ case Load: {
+ if (cast<LoadInst>(this)->isVolatile())
+ return false;
+ if (isa<AllocationInst>(getOperand(0)))
+ return true;
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(getOperand(0)))
+ return !GV->hasExternalWeakLinkage();
+ // FIXME: Handle cases involving GEPs. We have to be careful because
+ // a load of a out-of-bounds GEP has undefined behavior.
+ return false;
+ }
+ case Call:
+ return false; // The called function could have undefined behavior or
+ // side-effects.
+ // FIXME: We should special-case some intrinsics (bswap,
+ // overflow-checking arithmetic, etc.)
+ case VAArg:
+ case Alloca:
+ case Malloc:
+ case Invoke:
+ case PHI:
+ case Store:
+ case Free:
+ case Ret:
+ case Br:
+ case Switch:
+ case Unwind:
+ case Unreachable:
+ return false; // Misc instructions which have effects
+ }
+}