Training and utilization of neural branch predictor

An apparatus comprising:

• a neural branch predictor configured to provide neural branch predictions;
• a non-neural branch predictor configured to provide non-neural branch predictions;
• a filter configured to identify subset of branch instructions from an execution trace of instructions executed by a processor, wherein the identified subset of branch instructions have greater benefit from branch predictions made by a neural branch predictor than branch predictions made by a non-neural branch predictor;
• wherein the filter is configured to, during runtime:
• selectively direct the identified subset of branch instructions to the neural branch predictor and selectively direct the remaining branch instructions outside the identified subset of branch instructions to the non-neural branch predictor, without directing the remaining branch instructions to the neural branch predictor.

A method of branch prediction, the method comprising:

• identifying a subset of branch instructions from an execution trace of instructions executed by a processor, wherein:
• the identified subset of branch instructions have greater benefit from branch predictions made by a neural branch predictor than branch predictions made by a non-neural branch predictor;
• and
• determining that the identified subset of branch instructions have greater benefit from branch predictions made by the neural branch predictor than branch predictions made by the non-neural branch predictor comprises:
• determining, for each branch instruction in the execution trace:
• a frequency of the branch instruction in the execution trace and a difference between misprediction rates using the neural branch predictor and the non-neural branch predictor;
• and
• multiplying the difference by the frequency;
• and
• during runtime, selectively using the neural branch predictor for obtaining branch predictions of the identified subset of branch instructions, and the non-neural branch predictor for obtaining branch predictions for remaining branch instructions outside the identified subset of branch instructions.