1. A data cache comprising: a plurality of cache lines, wherein a first cache line of the plurality of cache lines includes a state indicator for indicating at least one of a plurality of states, wherein the plurality of states includes a speculative state configured to track a speculative modification to data in the first cache line, and wherein the speculative state enables the speculative modification to the data in the first cache line to be undone in response to an operation performed responsive to not reaching an instruction boundary during speculative execution of instructions; and wherein said data cache is controllable to evict a particular cache line of said plurality of cache lines to a speculative cache buffer, and wherein said speculative cache buffer comprises at least one state indicator corresponding to at least one cache line of said speculative cache buffer.