1.87 Regression: s390x-unknown-linux-gnu release build gets stuck #141287
Labels
A-LLVM
Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues.
C-bug
Category: This is a bug.
O-SystemZ
Target: SystemZ processors (s390x)
regression-from-stable-to-stable
Performance or correctness regression from one stable version to another.
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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konstin
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jieyouxu
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O-SystemZ
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@konstin do you have a link to the failing CI logs or anything to give us a bit more insights? Thanks |
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There's really not much there, it just hangs; with I can provide other specific logs if it helps. |
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We've unfortunately had two distinct LLVM compile time regressions in LLVM 20, both reported by the Fixes for both have been merged upstream and in the LLVM 20 branch here: |
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@konstin If you want to bother to build rustc with (upstream LLVM? our LLVM with the backported patches?) then you may be able to find out if that fixes your problem early. |
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Is there a sequence of commands for this? I tried the naive way and while llvm built, |
nikic
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A-LLVM
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The LLVM on nightly already has those fixes, so maybe try whether the hang is gone there? |
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Lovely, it passes on nightly and it's roughly twice as fast even (4min for the whole build)! |
jieyouxu
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jieyouxu
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E-needs-mcve
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Re-opening to track beta-backport (#141063). |
konstin
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May 26, 2025
Build s390x on nightly due to llvm performance regressions see rust-lang/rust#141287. To be undone when the llvm fixes land on stable. This should fix the timeouts in https://github.com/astral-sh/uv/actions/runs/15259826631/job/42915439608?pr=13576
zanieb
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May 27, 2025
Build s390x on nightly due to llvm performance regressions see rust-lang/rust#141287. To be undone when the llvm fixes land on stable. This should fix the timeouts in https://github.com/astral-sh/uv/actions/runs/15259826631/job/42915439608?pr=13576
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When upgrading https://github.com/astral-sh/uv (at 7f3e94a091f9f65b778ccc9ba7271887fad143c8) from Rust 1.86 to Rust 1.87, we found that the s390x-unknown-linux-gnu release build would get stuck at 100% CPU and never finish.
I expected to see this happen:
cargo +1.87 build --target s390x-unknown-linux-gnu --releasefinishesInstead, this happened:
cargo +1.87 build --target s390x-unknown-linux-gnu --releasegets stuck on 100% CPUWe discovered this in CI, where we're running on the native platform through docker and QEMU, but I can also reproduce this locally using zigbuild:
I can't use
cargo builddue to an unrelated error on both 1.86 and 1.87 (Relocations in generic ELF (EM: 22)). Debug builds pass on both versions. Unfortunately I can't provide an MRE as a passing build takes several minutes each time and a non-passing one gets stuck, making non-targeted minimization infeasible.Version it worked on
It most recently worked on:
rustc +1.86 --version --verbose:Version with regression
rustc +1.87 --version --verbose:The text was updated successfully, but these errors were encountered: