Test interaction of unions with non-zero/niche-filling optimization #60590
Conversation
This file contains 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
Notably this nails down part of the behavior that MaybeUninit assumes, e.g. that a Option<MaybeUninit<&u8>> does not take advantage of non-zero optimization, and thus is a safe construct.
|
(rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
nikomatsakis
requested changes
May 7, 2019
|
Added explanation, as well as a test of a non-non-zero/niche-filled enum in a union. |
nikomatsakis
approved these changes
May 16, 2019
|
@bors r+ rollup |
|
📌 Commit aa1db24 has been approved by |
bors
added
S-waiting-on-bors
Centril
reviewed
May 18, 2019
|
@bors r=nikomatsakis,Centril rollup |
|
📌 Commit a91ad60 has been approved by |
Centril
added a commit
to Centril/rust
that referenced
this pull request
May 19, 2019
…r=nikomatsakis,Centril Test interaction of unions with non-zero/niche-filling optimization Notably this nails down part of the behavior that MaybeUninit assumes, e.g. that a Option<MaybeUninit<&u8>> does not take advantage of non-zero optimization, and thus is a safe construct. It also verifies the status quo: that even unions that could theoretically take advantage of niches don't. (relevant: rust-lang#36394)
bors
added a commit
that referenced
this pull request
May 20, 2019
Rollup of 6 pull requests Successful merges: - #60590 (Test interaction of unions with non-zero/niche-filling optimization) - #60745 (Perform constant propagation into terminators) - #60895 (Enable thumbv7a-pc-windows-msvc target build end to end in rust/master) - #60908 (Fix lints handling in rustdoc) - #60960 (Stop using gensyms in HIR lowering) - #60962 (Fix data types indication) Failed merges: r? @ghost
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
Notably this nails down part of the behavior that MaybeUninit assumes, e.g. that a Option<MaybeUninit<&u8>> does not take advantage of non-zero optimization, and thus is a safe construct.
It also verifies the status quo: that even unions that could theoretically take advantage of niches don't. (relevant: #36394)