Intrinsic has incorrect return type. LLVM ERROR: Broken function found, compilation aborted. aarch64 / ARM / nightly

[spital]

Crate bytecount compilation fails with latest nightly on NanoPC-T6 (RK3588 ARM / aarch64).
It worked yesterday.

I tried this code:

cargo new bytecount_test && cd bytecount_test

cargo add bytecount

Updating crates.io index
  Adding bytecount v0.6.7 to dependencies.
         Features:
         - generic-simd
         - html_report
         - packed_simd
         - runtime-dispatch-simd
Updating crates.io index

cargo  +nightly-2023-11-20 build

Compiling bytecount v0.6.7
Intrinsic has incorrect return type!
ptr @llvm.aarch64.neon.ld1x4.v16i8.p0i8
in function _ZN4core9core_arch10arm_shared4neon9generated11vld1q_u8_x417hd6e0965b4ff7ff22E
LLVM ERROR: Broken function found, compilation aborted!
error: could not compile bytecount (lib)

cargo  +nightly-2023-11-19 build

Compiling bytecount v0.6.7
Compiling bytecount_test v0.1.0 (/home/pi/bytecount_test)
Finished dev [unoptimized + debuginfo] target(s) in 0.90s

uname -a

Linux NanoPC-T6 5.10.160 #7 SMP Thu Jul 20 15:53:55 CST 2023 aarch64 aarch64 aarch64 GNU/Linux

cat /etc/os-release

PRETTY_NAME="Ubuntu 22.04.3 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.3 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

I expected to see this happen: Finished dev [unoptimized + debuginfo] target(s) in 1.32s

Instead, this happened: LLVM ERROR: Broken function found, compilation aborted!

[Nilstrieb]

searched nightlies: from nightly-2023-11-19 to nightly-2023-11-20
regressed nightly: nightly-2023-11-20
searched commit range: 4cb3bee...9a66e44
regressed commit: d19980e

bisected with cargo-bisect-rustc v0.6.5

Host triple: aarch64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start 2023-11-19 --access github --end 2023-11-20 --regress error

looks like something in that PR changed ABI behavior and now LLVM and rustc disagree. Don't know who's wrong. @RalfJung @davidtwco

[RalfJung]

Hm, I don't know how that "unadjusted" ABI stuff works...

pub unsafe fn vld1q_s8_x4(a: *const i8) -> int8x16x4_t {
    #[allow(improper_ctypes)]
    extern "unadjusted" {
        #[cfg_attr(target_arch = "arm", link_name = "llvm.arm.neon.vld1x4.v16i8.p0i8")]
        #[cfg_attr(target_arch = "aarch64", link_name = "llvm.aarch64.neon.ld1x4.v16i8.p0i8")]
        fn vld1q_s8_x4_(a: *const i8) -> int8x16x4_t;
    }
vld1q_s8_x4_(a)
}

[RalfJung]

#118127 should fix this. I am not sure how to add a test.

[apiraino]

WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-high