id = 1780
title = "PowerPC mishandles xscmpudp instruction"
state = "opened"
created_at = "2023-07-23T02:53:14.731Z"
closed_at = "n/a"
labels = ["target: ppc", "workflow::Triaged"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1780"
host-os = "Ubuntu 20.04"
host-arch = "x86_64"
qemu-version = "7.0.0"
guest-os = "Ubuntu 20.04"
guest-arch = "PowerPC64"
description = """xscmpudp instruction is mishandled"""
reproduce = """1. Compile the attached program with VSX (e.g. `RUSTFLAGS=-Ctarget-feature=+vsx cargo build --target=powerpc64-unknown-linux-gnu`)
2. Run the program and expect assertions to pass.
3. See assertions fail."""
additional = """When VSX is disabled, the `fcmpu` instruction is emitted instead (and handled properly).  See the offending program:
```
pub fn main() {
    use std::hint::black_box;
    assert!(black_box(f64::NAN)
        .clamp(black_box(0f64), black_box(0f64))
        .is_nan());
}
```"""