Skip to content

Fix CopyPropagation regression (2) #46462

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Merged
merged 1 commit into from
Dec 4, 2017
Merged

Fix CopyPropagation regression (2) #46462

merged 1 commit into from
Dec 4, 2017

Conversation

sinkuu
Copy link
Contributor

@sinkuu sinkuu commented Dec 3, 2017 •
edited
Loading

Remaining part of MIR copyprop regression by (I think) #45380, which I missed in #45753.

fn foo(mut x: i32) -> i32 {
    let y = x;
    x = 123; // `x` is assigned only once in MIR, but cannot be propagated to `y`
    y
}

So any assignment to an argument cannot be propagated.

@rust-highfive
Copy link
Contributor

r? @nikomatsakis

(rust_highfive has picked a reviewer for you, use r? to override)

@arielb1
Copy link
Contributor

arielb1 commented Dec 3, 2017

@bors r+ rollup

@bors
Copy link
Collaborator

bors commented Dec 3, 2017

📌 Commit 17d6631 has been approved by arielb1

@kennytm kennytm added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Dec 3, 2017
frewsxcv added a commit to frewsxcv/rust that referenced this pull request Dec 3, 2017
@frewsxcv
Rollup merge of rust-lang#46462 - sinkuu:copyprop_reg2, r=arielb1
94dbbac 
Fix CopyPropagation regression (2)

Remaining part of MIR copyprop regression by (I think) rust-lang#45380, which I missed in rust-lang#45753.

```rust
fn foo(mut x: i32) -> i32 {
    let y = x;
    x = 123; // `x` is assigned only once in MIR, but cannot be propagated to `y`
    y
}
```

So any assignment to an argument cannot be propagated.
@frewsxcv frewsxcv mentioned this pull request Dec 3, 2017
Merged
bors added a commit that referenced this pull request Dec 3, 2017
@bors
Auto merge of #46482 - frewsxcv:rollup, r=frewsxcv
fdfbcf8 
Rollup of 8 pull requests

- Successful merges: #45957, #46260, #46432, #46442, #46454, #46462, #46465, #46473
- Failed merges:
@bors bors merged commit 17d6631 into rust-lang:master Dec 4, 2017
@sinkuu sinkuu deleted the copyprop_reg2 branch December 4, 2017 07:18
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees

@nikomatsakis nikomatsakis

Labels
S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion.
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
6 participants
@sinkuu @rust-highfive @arielb1 @bors @kennytm @nikomatsakis