Prediction entry allocation

A method comprising:

• storing, in training circuitry, one or more metrics associated with each of a plurality of control flow altering instructions, and a plurality of candidate multi-taken entries, each of the candidate multi-taken entries identifying:
• a multi-taken sequence of instructions in which control flow is diverted by a first control flow altering instruction to a series of instructions comprising a second control flow altering instruction that diverts control flow to a target address;
• and
• metadata indicative of a confidence associated with the candidate multi-taken sequence;
• and
• in response to both of the confidence associated with a given candidate multi-taken entry satisfying a confidence condition and the one or more metrics associated with at least one of the first control flow altering instruction and the second control flow altering instruction of the given candidate multi-taken entry satisfying a filter condition, allocating a prediction entry indicative of the multi-taken sequence identified in the given candidate multi-taken entry into prediction circuitry configured to predict control flow based on the prediction entry.

A non-transitory computer-readable medium storing computer-readable code for fabrication of an apparatus comprising:

• training circuitry configured to store one or more metrics associated with each of a plurality of control flow altering instructions, and a plurality of candidate multi-taken entries, each of the candidate multi-taken entries identifying:
• a multi-taken sequence of instructions in which control flow is diverted by a first control flow altering instruction to a series of instructions comprising a second control flow altering instruction that diverts control flow to a target address;
• and
• metadata indicative of a confidence associated with the candidate multi-taken sequence;
• and
• control circuitry responsive to both of the confidence associated with a given candidate multi-taken entry satisfying a confidence condition and the one or more metrics associated with at least one of the first control flow altering instruction and the second control flow altering instruction of the given candidate multi-taken entry satisfying a filter condition, to allocate a prediction entry indicative of the multi-taken sequence identified in the given candidate multi-taken entry into prediction circuitry configured to predict control flow based on the prediction entry.