1. A computer system for optimizing instructions, the computer system comprising: a processor including an instruction execution unit configured to execute instructions and an instruction optimization unit configured to optimize two or more instructions; and memory to store two or more machine instructions to be executed by the instruction execution unit, the computer system configured to perform a method comprising: identifying the two or more machine instructions as being eligible for optimization, wherein the being eligible comprises determining that the two or more machine instructions comprise a first instruction specifying a first target register and a second instruction specifying the first target register as a source register and a target register, wherein the second instruction is a next sequential instruction of the first instruction in program order, wherein the first instruction specifies a first function to be performed, and the second instruction specifies a second function to be performed; merging the two or more machine instructions into a single optimized internal instruction that is configured to perform functions of the two or more machine instructions employing operands specified by the two or more machine instructions, wherein the single optimized internal instruction specifies the first target register only as a single target register, wherein the single optimized internal instruction specifies the first and second function to be performed, and executing the single optimized internal instruction to perform the functions of the two or more machine instructions.