Intrinsics not inlined despite cfg.

[human-0]

Code

I tried this code:

#[cfg(
    all(
        any(target_arch = "x86", target_arch = "x86_64"),
        target_feature = "sse2"
    )
)]
fn some_fn(...) -> Something {
    #[cfg(target_arch = "x86")]
    use std::arch::x86::*;
    #[cfg(target_arch = "x86_64")]
    use std::arch::x86_64::*;
    unsafe {
        some_sse2_code
    }
}

I expected to see this happen: The SSE2 intrinsics would be inlined. The target_arch was native (skylake).

Instead, this happened: The intrinsics were not inlined, and required a function call each time. Some of the functions were just two moves and the operation, others had _ZN4core9core_arch3x868m128iExt8 in them.
e.g. _mm_or_si128 was just

vmovaps	xmm0, xmmword ptr [r8]
vxorps	xmm0, xmm0, xmmword ptr [rdx]
vmovaps	xmmword ptr [rcx], xmm0
ret

but _mm_sub_epi64 was more complex. Both intrinsics should have been inlined.

Version it worked on

It most recently worked on: rustc 1.50

Version with regression

rustc --version --verbose:

rustc 1.52.0-nightly (d6eaea1c8 2021-03-14)
binary: rustc
commit-hash: d6eaea1c8860adb5302d2fbaad409e36585ab217
commit-date: 2021-03-14
host: x86_64-pc-windows-msvc
release: 1.52.0-nightly
LLVM version: 12.0.0

[nikic]

Probably a duplicate of #83027.

[human-0]

Indeed it is.