`powi` miscompiles on x86 uefi targets

I tried this code:

#[no_mangle]
fn f(x: f32, n: i32) -> f32 {
    x.powi(n)
}

cargo build --target x86_64-unknown-uefi

I expected to see this happen: it compiles and works

Since 1.87

Instead, it compiles to

std::f32::<impl f32>::powi::hc33784da3254b978:
        sub     rsp, 16
        mov     dword ptr [rsp + 4], ecx
        mov     dword ptr [rsp + 8], edx
        mov     eax, dword ptr [rsp + 12]
        add     rsp, 16
        ret

Before 1.87

Instead, this happened:

error: Don't know how to soften fpowi to fpow

Same error on i686-unknown-uefi, but not on aarch64-unknown-uefi.

Meta

rustc --version --verbose:

rustc 1.83.0 (90b35a623 2024-11-26)
binary: rustc
commit-hash: 90b35a6239c3d8bdabc530a6a0816f7ff89a0aaf
commit-date: 2024-11-26
host: x86_64-unknown-linux-gnu
release: 1.83.0
LLVM version: 19.1.1

Start by reproducing the minimal Rust f32::powi example with cargo build --target x86_64-unknown-uefi, then compare x86_64 and i686 UEFI behavior with aarch64 and with versions before and after 1.87. Done means powi compiles correctly for x86 UEFI targets and the resulting function works as expected rather than emitting the shown stub or softening error.