GH-120024: Change LOAD_FAST instructions to LOAD_FAST_TEMP when it is guaranteed the reference is consumed immediately.#125192
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markshannon changed the title LOAD_FAST instructions to LOAD_FAST_TEMP when it is guaranteed the reference is consumed immediately.
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markshannon commented Mar 3, 2025
Superseded by #130708 |
markshannon deleted the mark-load-fast-deferred-for-guaranteed-consumed-refs branch Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment
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This PR adds a
LOAD_FAST_TEMPinstruction for loading locals to the evaluation stack that are used as short-lived values within an expression. Distinguishing theseLOAD_FASTinstructions will allow us to avoid expensive reference counting operations in these cases.This is marked as draft, as it has no value until the default build supports reference counts in tags.
The stats show that 3/4 of all
LOAD_FAST(including theLOAD_FASTs inLOAD_FAST_LOAD_FAST) are converted toLOAD_FAST_TEMP.Before merging, a few tests need fixing and the choice of superinstructions needs updating.