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@cuviper cuviper commented Dec 20, 2025

Kivooeo and others added 3 commits December 20, 2025 13:54
(cherry picked from commit f33abb1)
…owedBuf` and `BorrowedCursor`)

This caused several performance regressions because of existing code
which uses `Read::read` and therefore requires full buffer
initialization. This is particularly a problem when the same buffer is
re-used for multiple read calls since this means it needs to be fully
re-initialized each time.

There is still some benefit to landing the API changes, but we will have
to add private APIs so that the existing infrastructure can
track and avoid redundant initialization.

(cherry picked from commit 4b07875)
@rustbot rustbot added A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. O-SGX Target: SGX O-windows Operating system: Windows S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Dec 20, 2025
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rustbot commented Dec 20, 2025

⚠️ Warning ⚠️

  • Some commits in this PR modify submodules.

    If this was not intentional, see I changed a submodule on accident in the rustc dev guide.

  • There are issue links (such as #123) in the commit messages of the following commits.
    Please move them to the PR description, to avoid spamming the issues with references to the commit, and so this bot can automatically canonicalize them to avoid issues with subtree.

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Kivooeo commented Dec 20, 2025

can you please also add this one #150056, this is a follow up on #149664

so i feel like it would be nice if we could backbort them together

or replace #149664 with #150056, since latter one is fixes perf and self-sufficient

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cuviper commented Dec 20, 2025

@Kivooeo, we (release team) do these backports mechanically based on the owning team's approvals, and that one doesn't have beta-accepted yet. Looks good so far in the zulip thread though!

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Kivooeo commented Dec 20, 2025

oh, it still wasn't been approved on a backport, yeah, i see it makes sense

i just got concerned in a moment that less performant version will get into the beta and the one with better performance is not

but now i feel like we still have a bunch of time, and it shouldnt be a problem, right? like, the second version will anyway gets in beta

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cuviper commented Dec 20, 2025

Yes, we're still quite early in the beta phase -- 1.93 release isn't until January 22.

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cuviper commented Dec 20, 2025

@bors r+ rollup=never p=1

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bors commented Dec 20, 2025

📌 Commit 4bc6d75 has been approved by cuviper

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 20, 2025
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bors commented Dec 21, 2025

⌛ Testing commit 4bc6d75 with merge 72b6488...

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bors commented Dec 21, 2025

☀️ Test successful - checks-actions
Approved by: cuviper
Pushing 72b6488 to beta...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Dec 21, 2025
@bors bors merged commit 72b6488 into rust-lang:beta Dec 21, 2025
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@rustbot rustbot added this to the 1.93.0 milestone Dec 21, 2025
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A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. merged-by-bors This PR was explicitly merged by bors. O-SGX Target: SGX O-windows Operating system: Windows S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue.

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6 participants