[ICE]: Multiple hangs with specific compiler options

[wxie7]

Code

EDIT: dropped not required flags

timeout 30 /path/to/rustc --crate-type staticlib -C link-dead-code -C debuginfo=2 -C opt-level=3 -Z mir-opt-level=3 file.rs

Affected release channels

• Previous Stable
• Current Stable
• Current Beta
• Current Nightly

Rust Version

$ rustc -Vv
rustc 1.84.0-nightly (b8c8287 2024-11-03)
binary: rustc
commit-hash: b8c8287
commit-date: 2024-11-03
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Current error output

No response

Backtrace

no backtrace

Anything else?

The attached files contain multiple source codes that cause the compiler to hang.
hangs.zip

[jieyouxu]

-Z unsound-mir-opts=yes

Well...

[jieyouxu]

@wxie7 does the hang repro without -Z unsound-mir-opts=yes, because unsound mir-opts are, like the flag name suggests, unsound.

Marking as S-needs-repro for a repro that uh repros without unsound mir-opts.

[jieyouxu]

And even better, does the hang repro with fewer flags?

[wxie7]

@jieyouxu Even after removing -Z unsound-mir-opts=yes -Z polonius=next -Z polymorphize=yes flags, the compiler still hangs.

[jieyouxu]

We'll need to cleanup the code examples produced via mutation testing (run through rustfmt, trim down irrelevant errors, etc.)

[jieyouxu]

And also, to clarify @wxie7 do they produce Internal Compiler Errors (ICE) which is usually associated with an ICE message, or do they just hang (i.e. don't terminate)?

[jieyouxu]

Thank you for the report, it would be very helpful next time if you indicated that these hangs are found via some kind of fuzzing, see the fuzzing guidelines in the dev-guide.