SELECTIVELY PERFORMING FETCHES FOR STORE OPERATIONS DURING SPECULATIVE EXECUTION

摘要

One embodiment of the present invention provides a processor which selectively fetches cache lines for store instructions during speculative-execution. During normal execution, the processor issues instructions for execution in program order. Upon encountering an instruction which generates a launch condition, the processor performs a checkpoint and begins the execution of instructions in a speculative-execution mode. Upon encountering a store instruction during the speculative-execution mode, the processor checks an L1 data cache for a matching cache line and checks a store buffer for a store to a matching cache line. If a matching cache line is already present in the L1 data cache or if the store to a matching cache line is already present in the store buffer, the processor suppresses generation of the fetch for the cache line. Otherwise, the processor generates a fetch for the cache line.