Mark more locals as moved to avoid building drops for them.#158281
Open
cjgillot wants to merge 4 commits into
Open
Mark more locals as moved to avoid building drops for them.#158281cjgillot wants to merge 4 commits into
cjgillot wants to merge 4 commits into
Conversation
This removes a few false-positives due to extraneous drops.
And some more cases along the way. We have a specific optimization to avoid generating useless drops, use it. In particular, aggregate construction are very similar to function calls for which this is designed.
Collaborator
|
Some changes occurred to MIR optimizations cc @rust-lang/wg-mir-opt |
Collaborator
|
r? @JohnTitor rustbot has assigned @JohnTitor. Use Why was this reviewer chosen?The reviewer was selected based on:
|
Contributor
|
Does this have user-visible behavior changes? e.g., see #156713 |
Contributor
Author
|
Yes. With this change, both cases in #156713 pass. We also have a few user-visible consequences with the drop order lint. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
MIR building skips generating drops for moved-from locals in the topmost scope. This was only used for call terminators, but can be generalized to many other moves. This PR generalizes this to aggregate construction and many other assignments.
This avoids generating drops that would then be removed by drop elaboration.
Based on #158279 to remove a lint false-positive