Array as asm output ICEs LLVM

[kmcallister]

#![feature(asm)]

fn main() {
    let arr: [u8; 16];
    unsafe { asm!("" : "=m"(arr)); }
    println!("{:?}", arr);
}

$ rustc --version
rustc 1.0.0-dev (896cb36ec 2015-01-14 12:19:58 +0000)

$ rustc foo.rs
Unknown type!
UNREACHABLE executed at /home/keegan/rust-master/src/llvm/lib/IR/ValueTypes.cpp:251!
Aborted

[erickt]

visiting for triage. Still reproducible.

[steveklabnik]

Triage: still reproduces

[kmcallister]

Updated the code.

[tamird]

Triage: this is worse now - no longer an ICE, this now causes all kinds of failures:

$ rustc --version
rustc 1.0.0-dev (f46c4e158 2015-04-20) (built 2015-04-20)
$ rustc src/bin/main.rs
Segmentation fault: 11
$ rustc src/bin/main.rs
Segmentation fault: 11
$ rustc src/bin/main.rs
Segmentation fault: 11
$ RUST_BACKTRACE=1 rustc src/bin/main.rs
Illegal instruction: 4
$ RUST_BACKTRACE=1 rustc src/bin/main.rs
Segmentation fault: 11
$ RUST_BACKTRACE=1 rustc src/bin/main.rs
Segmentation fault: 11
$ RUST_BACKTRACE=1 rustc src/bin/main.rs
Illegal instruction: 4

[kmcallister]

I don't remember whether we now disable LLVM assertions by default, but that might explain the change.

[dotdash]

LLVM assertions are off by default now, only with --enable-llvm-assertions or --enable-debug and the nightly channel have them enabled. @tamird could you please check whether LLVM assertions are enabled in your rustc, and if not, re-check this and any other issues that you triaged that were about LLVM assertions? Thanks!

[jooert]

With LLVM assertions enabled, this still fails with the original error.

[jethrogb]

Possibly related to #15402