LLVM codegen errors with `Invalid insertelement operands` in latest nightlies

[AlexTMjugador]

Code

https://github.com/ComunidadAylas/PackSquash/tree/8ddb8451b4c4102188e6807233feac6cb4091872

Meta

rustc --version --verbose:

1.78.0-nightly (a4472498d 2024-02-15)

Error output

Can be seen in more detail in GitHub Actions workflow output logs:

Notes

This is a pretty low-level LLVM codegen error that does not really fit the bill of an internal rustc compile error, as it happens at a layer below rustc, but I picked this report template because it seems like a pretty "internal" issue with the Rust compiler nevertheless.

I didn't dive into the precise cause of this error at all, but judging from the error messages, it seems related to rustc generating bad LLVM IR for the rustfft crate.

On my CI setup, the issue only happens for Linux and macOS x64 targets. Windows x64 and Linux and macOS AArch64 targets build fine.

[nikic]

How should one reproduce this? cargo +nightly build --release works fine for me (on x64 Linux).

[nikic]

Ah, I get the error with cargo +nightly test --release.

[nikic]

Repro: opt -passes=slp-vectorizer on https://gist.github.com/nikic/94ef389d1ba1ac6ce9c327a54426e92b.

Does not reproduce with LLVM trunk.

[nikic]

Looks like this has been fixed by llvm/llvm-project@48bbd76.

[AlexTMjugador]

Thanks for looking into the issue! The reproduction step is indeed to run cargo +nightly test --release on the linked code. A cargo build works fine for me too.