1. A method for implementation in a processor-based system, comprising: selecting a first subset of instructions, wherein each instruction in the first subset is the earliest in program order of instructions associated with a corresponding one of a plurality of sub-matrices of a matrix having a plurality of matrix entries, each matrix entry comprising a bit position indicating the program order of one pair of instructions that are eligible for execution; and selecting, from the first subset of instructions, the instruction that is earliest in program order based on the bit positions for each pair of instructions within the first subset of instructions.