Abstract: Register halves are allocated independently when performing register allocation during program compilation, thereby effectively doubling the number of registers which are available for allocation, which in turn may reduce spill code and improve run-time performance. When hardware registers are 64 bits wide, for example, an architecture supporting the present invention provides some number of separate hardware instructions that operate on the 32-bit high-word and/or the 32-bit low word of the hardware registers as if those 32-bit words are separate registers. Such hardware instructions are able to manipulate the register halves independently, leaving the other register half untouched. A register coloring algorithm using in the compilation process is invoked using the number of register halves, instead of the number of hardware registers.

Abstract: Register halves are allocated independently when performing register allocation during program compilation, thereby effectively doubling the number of registers which are available for allocation, which in turn may reduce spill code and improve run-time performance. When hardware registers are 64 bits wide, for example, an architecture supporting the present invention provides some number of separate hardware instructions that operate on the 32-bit high-word and/or the 32-bit low word of the hardware registers as if those 32-bit words are separate registers. Such hardware instructions are able to manipulate the register halves independently, leaving the other register half untouched. A register coloring algorithm using in the compilation process is invoked using the number of register halves, instead of the number of hardware registers.