Selective use of branch prediction hints
AssigneeIntel Corporation
InventorsJared W. Stark, Ahmad Yasin, Ajay Amarsingh Singh
Life of this patent
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Abstract
Embodiments of apparatuses, methods, and systems for selective use of branch prediction hints are described. In an embodiment, an apparatus includes an instruction decoder and a branch predictor. The instruction decoder is to decode a branch instruction having a hint. The branch predictor is to provide a prediction and a hint-override indicator. The hint-override indicator is to indicate whether the prediction is based on stored information about the branch instruction. The prediction is to override the hint if the hint-override indicator indicates that the prediction is based on stored information about the branch instruction.
Claims20
An apparatus comprising:
- an instruction decoder to decode a branch instruction having a hint;
- and
- a branch predictor to provide a prediction to override the hint if the prediction is based on stored information about the branch instruction.
A method comprising:
- receiving, by a branch predictor, a branch instruction with a hint;
- making a prediction;
- determining whether the prediction was based on stored information about the branch instruction;
- and
- overriding the hint if the prediction was based on stored information.
A method comprising:
- executing code including branch instructions having hints on a processor having a branch predictor to provide a prediction;
- overriding the hints if the prediction is based on stored information about the corresponding branch instruction;
- and
- counting mispredictions for conditional branch instructions for which the branch predictor had no stored information and for which the prediction was to not take a branch.
Dependencies are inferred from the claim text.