Use dense fetches in Query::get and Query::iter_many #12501
+80
−43
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Objective
Found while investigating #12476 and #12474. Apparently the Rust compiler cannot optimize out the archetype fetch if it's not used by the fetch type in
QueryState::get_unchecked_manual
.Solution
Use the same technique for branching on constants to use dense fetches instead of archetypal fetches. The generated assembly confirms that there's one less memory access for calls to
Query::get
on dense queries.Performance
TODO: Microbenchmark