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//===-- llvm/Instruction.h - Instruction class definition -------*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file contains the declaration of the Instruction class, which is the
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// base class for all of the LLVM instructions.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_INSTRUCTION_H
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#define LLVM_INSTRUCTION_H
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#include "llvm/User.h"
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#include "llvm/ADT/ilist_node.h"
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template<typename ValueSubClass, typename ItemParentClass>
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class SymbolTableListTraits;
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class Instruction : public User, public ilist_node<Instruction> {
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void operator=(const Instruction &); // Do not implement
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Instruction(const Instruction &); // Do not implement
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/// HasMetadataBit - This is a bit stored in the SubClassData field which
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/// indicates whether this instruction has metadata attached to it or not.
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HasMetadataBit = 1 << 15
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// Out of line virtual method, so the vtable, etc has a home.
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/// use_back - Specialize the methods defined in Value, as we know that an
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/// instruction can only be used by other instructions.
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Instruction *use_back() { return cast<Instruction>(*use_begin());}
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const Instruction *use_back() const { return cast<Instruction>(*use_begin());}
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inline const BasicBlock *getParent() const { return Parent; }
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inline BasicBlock *getParent() { return Parent; }
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/// removeFromParent - This method unlinks 'this' from the containing basic
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/// block, but does not delete it.
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void removeFromParent();
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/// eraseFromParent - This method unlinks 'this' from the containing basic
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/// block and deletes it.
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void eraseFromParent();
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/// insertBefore - Insert an unlinked instructions into a basic block
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/// immediately before the specified instruction.
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void insertBefore(Instruction *InsertPos);
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/// insertAfter - Insert an unlinked instructions into a basic block
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/// immediately after the specified instruction.
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void insertAfter(Instruction *InsertPos);
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/// moveBefore - Unlink this instruction from its current basic block and
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/// insert it into the basic block that MovePos lives in, right before
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void moveBefore(Instruction *MovePos);
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//===--------------------------------------------------------------------===//
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// Subclass classification.
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//===--------------------------------------------------------------------===//
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/// getOpcode() returns a member of one of the enums like Instruction::Add.
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unsigned getOpcode() const { return getValueID() - InstructionVal; }
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const char *getOpcodeName() const { return getOpcodeName(getOpcode()); }
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bool isTerminator() const { return isTerminator(getOpcode()); }
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bool isBinaryOp() const { return isBinaryOp(getOpcode()); }
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bool isShift() { return isShift(getOpcode()); }
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bool isCast() const { return isCast(getOpcode()); }
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static const char* getOpcodeName(unsigned OpCode);
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static inline bool isTerminator(unsigned OpCode) {
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return OpCode >= TermOpsBegin && OpCode < TermOpsEnd;
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static inline bool isBinaryOp(unsigned Opcode) {
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return Opcode >= BinaryOpsBegin && Opcode < BinaryOpsEnd;
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/// @brief Determine if the Opcode is one of the shift instructions.
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static inline bool isShift(unsigned Opcode) {
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return Opcode >= Shl && Opcode <= AShr;
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/// isLogicalShift - Return true if this is a logical shift left or a logical
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inline bool isLogicalShift() const {
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return getOpcode() == Shl || getOpcode() == LShr;
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/// isArithmeticShift - Return true if this is an arithmetic shift right.
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inline bool isArithmeticShift() const {
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return getOpcode() == AShr;
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/// @brief Determine if the OpCode is one of the CastInst instructions.
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static inline bool isCast(unsigned OpCode) {
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return OpCode >= CastOpsBegin && OpCode < CastOpsEnd;
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//===--------------------------------------------------------------------===//
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// Metadata manipulation.
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//===--------------------------------------------------------------------===//
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/// hasMetadata() - Return true if this instruction has any metadata attached
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bool hasMetadata() const {
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return (getSubclassDataFromValue() & HasMetadataBit) != 0;
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/// getMetadata - Get the metadata of given kind attached to this Instruction.
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/// If the metadata is not found then return null.
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MDNode *getMetadata(unsigned KindID) const {
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if (!hasMetadata()) return 0;
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return getMetadataImpl(KindID);
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/// getMetadata - Get the metadata of given kind attached to this Instruction.
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/// If the metadata is not found then return null.
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MDNode *getMetadata(const char *Kind) const {
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if (!hasMetadata()) return 0;
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return getMetadataImpl(Kind);
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/// getAllMetadata - Get all metadata attached to this Instruction. The first
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/// element of each pair returned is the KindID, the second element is the
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/// metadata value. This list is returned sorted by the KindID.
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void getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode*> > &MDs)const{
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getAllMetadataImpl(MDs);
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/// setMetadata - Set the metadata of the specified kind to the specified
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/// node. This updates/replaces metadata if already present, or removes it if
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void setMetadata(unsigned KindID, MDNode *Node);
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void setMetadata(const char *Kind, MDNode *Node);
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// These are all implemented in Metadata.cpp.
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MDNode *getMetadataImpl(unsigned KindID) const;
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MDNode *getMetadataImpl(const char *Kind) const;
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void getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,MDNode*> > &)const;
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void removeAllMetadata();
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//===--------------------------------------------------------------------===//
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// Predicates and helper methods.
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//===--------------------------------------------------------------------===//
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/// isAssociative - Return true if the instruction is associative:
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/// Associative operators satisfy: x op (y op z) === (x op y) op z
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/// In LLVM, the Add, Mul, And, Or, and Xor operators are associative, when
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/// not applied to floating point types.
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bool isAssociative() const { return isAssociative(getOpcode(), getType()); }
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static bool isAssociative(unsigned op, const Type *Ty);
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/// isCommutative - Return true if the instruction is commutative:
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/// Commutative operators satisfy: (x op y) === (y op x)
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/// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
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/// applied to any type.
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bool isCommutative() const { return isCommutative(getOpcode()); }
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static bool isCommutative(unsigned op);
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/// mayWriteToMemory - Return true if this instruction may modify memory.
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bool mayWriteToMemory() const;
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/// mayReadFromMemory - Return true if this instruction may read memory.
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bool mayReadFromMemory() const;
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/// mayThrow - Return true if this instruction may throw an exception.
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bool mayThrow() const;
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/// mayHaveSideEffects - Return true if the instruction may have side effects.
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/// Note that this does not consider malloc and alloca to have side
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/// effects because the newly allocated memory is completely invisible to
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/// instructions which don't used the returned value. For cases where this
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/// matters, isSafeToSpeculativelyExecute may be more appropriate.
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bool mayHaveSideEffects() const {
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return mayWriteToMemory() || mayThrow();
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/// isSafeToSpeculativelyExecute - Return true if the instruction does not
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/// have any effects besides calculating the result and does not have
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/// undefined behavior.
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/// This method never returns true for an instruction that returns true for
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/// mayHaveSideEffects; however, this method also does some other checks in
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/// addition. It checks for undefined behavior, like dividing by zero or
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/// loading from an invalid pointer (but not for undefined results, like a
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/// shift with a shift amount larger than the width of the result). It checks
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/// for malloc and alloca because speculatively executing them might cause a
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/// memory leak. It also returns false for instructions related to control
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/// flow, specifically terminators and PHI nodes.
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/// This method only looks at the instruction itself and its operands, so if
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/// this method returns true, it is safe to move the instruction as long as
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/// the correct dominance relationships for the operands and users hold.
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/// However, this method can return true for instructions that read memory;
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/// for such instructions, moving them may change the resulting value.
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bool isSafeToSpeculativelyExecute() const;
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/// clone() - Create a copy of 'this' instruction that is identical in all
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/// ways except the following:
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/// * The instruction has no parent
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/// * The instruction has no name
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Instruction *clone() const;
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/// isIdenticalTo - Return true if the specified instruction is exactly
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/// identical to the current one. This means that all operands match and any
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/// extra information (e.g. load is volatile) agree.
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bool isIdenticalTo(const Instruction *I) const;
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/// isIdenticalToWhenDefined - This is like isIdenticalTo, except that it
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/// ignores the SubclassOptionalData flags, which specify conditions
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/// under which the instruction's result is undefined.
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bool isIdenticalToWhenDefined(const Instruction *I) const;
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/// This function determines if the specified instruction executes the same
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/// operation as the current one. This means that the opcodes, type, operand
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/// types and any other factors affecting the operation must be the same. This
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/// is similar to isIdenticalTo except the operands themselves don't have to
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/// @returns true if the specified instruction is the same operation as
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/// @brief Determine if one instruction is the same operation as another.
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bool isSameOperationAs(const Instruction *I) const;
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/// isUsedOutsideOfBlock - Return true if there are any uses of this
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/// instruction in blocks other than the specified block. Note that PHI nodes
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/// are considered to evaluate their operands in the corresponding predecessor
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bool isUsedOutsideOfBlock(const BasicBlock *BB) const;
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/// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const Instruction *) { return true; }
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static inline bool classof(const Value *V) {
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return V->getValueID() >= Value::InstructionVal;
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//----------------------------------------------------------------------
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// Exported enumerations.
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enum TermOps { // These terminate basic blocks
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#define FIRST_TERM_INST(N) TermOpsBegin = N,
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#define HANDLE_TERM_INST(N, OPC, CLASS) OPC = N,
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#define LAST_TERM_INST(N) TermOpsEnd = N+1
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#include "llvm/Instruction.def"
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#define FIRST_BINARY_INST(N) BinaryOpsBegin = N,
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#define HANDLE_BINARY_INST(N, OPC, CLASS) OPC = N,
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#define LAST_BINARY_INST(N) BinaryOpsEnd = N+1
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#include "llvm/Instruction.def"
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#define FIRST_MEMORY_INST(N) MemoryOpsBegin = N,
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#define HANDLE_MEMORY_INST(N, OPC, CLASS) OPC = N,
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#define LAST_MEMORY_INST(N) MemoryOpsEnd = N+1
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#include "llvm/Instruction.def"
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#define FIRST_CAST_INST(N) CastOpsBegin = N,
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#define HANDLE_CAST_INST(N, OPC, CLASS) OPC = N,
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#define LAST_CAST_INST(N) CastOpsEnd = N+1
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#include "llvm/Instruction.def"
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#define FIRST_OTHER_INST(N) OtherOpsBegin = N,
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#define HANDLE_OTHER_INST(N, OPC, CLASS) OPC = N,
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#define LAST_OTHER_INST(N) OtherOpsEnd = N+1
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#include "llvm/Instruction.def"
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// Shadow Value::setValueSubclassData with a private forwarding method so that
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// subclasses cannot accidentally use it.
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void setValueSubclassData(unsigned short D) {
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Value::setValueSubclassData(D);
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unsigned short getSubclassDataFromValue() const {
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return Value::getSubclassDataFromValue();
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void setHasMetadata(bool V) {
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setValueSubclassData((getSubclassDataFromValue() & ~HasMetadataBit) |
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(V ? HasMetadataBit : 0));
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friend class SymbolTableListTraits<Instruction, BasicBlock>;
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void setParent(BasicBlock *P);
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// Instruction subclasses can stick up to 15 bits of stuff into the
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// SubclassData field of instruction with these members.
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// Verify that only the low 15 bits are used.
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void setInstructionSubclassData(unsigned short D) {
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assert((D & HasMetadataBit) == 0 && "Out of range value put into field");
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setValueSubclassData((getSubclassDataFromValue() & HasMetadataBit) | D);
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unsigned getSubclassDataFromInstruction() const {
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return getSubclassDataFromValue() & ~HasMetadataBit;
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Instruction(const Type *Ty, unsigned iType, Use *Ops, unsigned NumOps,
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Instruction *InsertBefore = 0);
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Instruction(const Type *Ty, unsigned iType, Use *Ops, unsigned NumOps,
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BasicBlock *InsertAtEnd);
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virtual Instruction *clone_impl() const = 0;
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// Instruction* is only 4-byte aligned.
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class PointerLikeTypeTraits<Instruction*> {
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typedef Instruction* PT;
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static inline void *getAsVoidPointer(PT P) { return P; }
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static inline PT getFromVoidPointer(void *P) {
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return static_cast<PT>(P);
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enum { NumLowBitsAvailable = 2 };
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} // End llvm namespace