1. A computer processor, comprising: a plurality of storage arrays, each comprising a plurality of bits, wherein each bit corresponds to a respective position within the storage array; an execution core configured to store an indication that a given value is a member of a set of values, including by: executing an architected instruction having an operand specifying the given value, wherein said executing comprises applying a hash function to the given value to determine an index value; determining one of the plurality of storage arrays as a target storage array; and setting a bit in the target storage array, wherein the position of the set bit within the target storage array corresponds to the determined index value.