closure doesn't seem to inherit the target attributes for codegen purposes

[sarah-ek]

I tried this code:

#![feature(avx512_target_feature)]
#![feature(stdsimd)]

#[target_feature(enable = "lzcnt,avx512f")]
pub unsafe fn test(a: &mut [u64]) {
    let mut f = move || {
        std::arch::x86_64::_mm512_mask_loadu_epi64(
            std::arch::x86_64::_mm512_setzero_si512(),
            0,
            a.as_mut_ptr() as *mut i64,
        );
    };
    f()
}

I expected to see this happen: all the avx512f functions get inlined into test

Instead, this happened: _mm512_mask_loadu_epi64 did not get inlined into test

codegen: https://godbolt.org/z/PbvexEWd8

here's a repro that mostly doesn't depend on std

#![feature(avx512_target_feature)]
#![feature(stdsimd)]
#![feature(repr_simd)]

#[repr(simd)]
#[allow(non_camel_case_types)]
#[derive(Copy, Clone)]
pub struct __m512i(i64, i64, i64, i64, i64, i64, i64, i64);

#[inline]
#[target_feature(enable = "avx512f")]
pub unsafe fn asm_fn(_: __m512i) -> __m512i {
    let mut dst = __m512i(0, 0, 0, 0, 0, 0, 0, 0);
    core::arch::asm!(
        "/* {dst} */",
        dst = inout(zmm_reg) dst,
    );
    dst
}

#[inline]
#[target_feature(enable = "avx512f")]
unsafe fn do_nothing() {}

#[target_feature(enable = "lzcnt,avx512f")]
pub unsafe fn test() {
    ({
        #[inline(always)]
        move || {
            do_nothing();
            asm_fn(__m512i(0, 0, 0, 0, 0, 0, 0, 0));
        }
    })();
}

codegen: https://godbolt.org/z/joG9xxq4c

there seem to be quite a few moving parts here.

• if i remove the lzcnt feature (or replace it with a feature that is implied by avx512f),
• or if i remove the inout parameter in the asm in asm_fn,
• or if i remove the call to do_nothing,
• or if i take the code outside the closure,

the function gets inlined as expected, so i'm not sure which is the culprit here

Meta

rustc --version --verbose:

rustc 1.69.0-nightly (5243ea5c2 2023-02-20)
binary: rustc
commit-hash: 5243ea5c29b136137c36bd773e5baa663790e097
commit-date: 2023-02-20
host: x86_64-unknown-linux-gnu
release: 1.69.0-nightly
LLVM version: 15.0.7

[programmerjake]

the closure doesn't have any target features enabled, which isn't supposed to happen according to #73631.

llvm ir before any llvm passes: https://godbolt.org/z/36fYKWbr8

link to original zulip discussion: https://rust-lang.zulipchat.com/#narrow/stream/257879-project-portable-simd/topic/weird.20codegen.20with.20_mm512_mask_loadu_epi64.20and.20lzcnt/near/329359963

[eduardosm]

This works correctly if you add #![feature(target_feature_11)]. It looks like it was done on purpose.