An apparatus and method for detecting and eliminating loop-invariant instructions. For example, one embodiment of a method comprises: detecting a loop start; responsively setting the loop-invariant bit for each register entry in a register alias table; executing first N iterations of the loop and responsively clearing the loop-invariant bit of any register modified during the first N iterations of the loop; identifying one or more loop-invariant registers based on the status of the loop-invariant bit in the register alias table; identifying one or more loop-invariant instructions based on the loop-invariant registers; and propagating the identified loop-invariant instructions by storing the destination register's values in a physical register file for later reuse by other instructions.
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