(*--... Operations on users ................................................--*)
external operand : llvalue -> int -> llvalue = "llvm_operand"
+external operand_use : llvalue -> int -> lluse = "llvm_operand_use"
external set_operand : llvalue -> int -> llvalue -> unit = "llvm_set_operand"
external num_operands : llvalue -> int = "llvm_num_operands"