+ /// isLogicalShift - Return true if this is a logical shift left or a logical
+ /// shift right.
+ inline bool isLogicalShift() const {
+ return getOpcode() == Shl || getOpcode() == LShr;
+ }
+
+ /// isArithmeticShift - Return true if this is an arithmetic shift right.
+ inline bool isArithmeticShift() const {
+ return getOpcode() == AShr;
+ }
+
+ /// @brief Determine if the OpCode is one of the CastInst instructions.
+ static inline bool isCast(unsigned OpCode) {
+ return OpCode >= CastOpsBegin && OpCode < CastOpsEnd;
+ }
+
+ /// 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, when
+ /// not applied to floating point types.
+ ///
+ bool isAssociative() const { return isAssociative(getOpcode(), getType()); }
+ static bool isAssociative(unsigned op, const Type *Ty);
+
+ /// 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 isCommutative() const { return isCommutative(getOpcode()); }
+ static bool isCommutative(unsigned op);
+
+ /// mayWriteToMemory - Return true if this instruction may modify memory.
+ ///
+ bool mayWriteToMemory() const;
+
+ /// mayReadFromMemory - Return true if this instruction may read memory.
+ ///
+ bool mayReadFromMemory() const;
+
+ /// mayThrow - Return true if this instruction may throw an exception.
+ ///
+ bool mayThrow() const;
+
+ /// mayHaveSideEffects - Return true if the instruction may have side effects.
+ ///
+ /// Note that this does not consider malloc and alloca to have side
+ /// effects because the newly allocated memory is completely invisible to
+ /// instructions which don't used the returned value. For cases where this
+ /// matters, isSafeToSpeculativelyExecute may be more appropriate.
+ bool mayHaveSideEffects() const {
+ return mayWriteToMemory() || mayThrow();
+ }
+
+ /// isSafeToSpeculativelyExecute - Return true if the instruction does not
+ /// have any effects besides calculating the result and does not have
+ /// undefined behavior.
+ ///
+ /// This method never returns true for an instruction that returns true for
+ /// mayHaveSideEffects; however, this method also does some other checks in
+ /// addition. It checks for undefined behavior, like dividing by zero or
+ /// loading from an invalid pointer (but not for undefined results, like a
+ /// shift with a shift amount larger than the width of the result). It checks
+ /// for malloc and alloca because speculatively executing them might cause a
+ /// memory leak. It also returns false for instructions related to control
+ /// flow, specifically terminators and PHI nodes.
+ ///
+ /// This method only looks at the instruction itself and its operands, so if
+ /// this method returns true, it is safe to move the instruction as long as
+ /// the correct dominance relationships for the operands and users hold.
+ /// However, this method can return true for instructions that read memory;
+ /// for such instructions, moving them may change the resulting value.
+ bool isSafeToSpeculativelyExecute() const;
+
+ /// Methods for support type inquiry through isa, cast, and dyn_cast:
+ static inline bool classof(const Instruction *) { return true; }