Rust 1.93.0 Release

// This program demonstrates the new ability to apply cfg attributes to individual
// statements inside an asm! block.  The feature is available in Rust 1.93.0, but
// the current sandbox uses Rust 1.98.1 (edition 2024), so we import the asm
// macro explicitly.  The program prints a message that shows whether the
// target supports the "sse2" feature; the asm block will only emit the
// second "nop" if that feature is enabled.

use std::arch::asm;

fn main() {
    // Detect if the target CPU supports SSE2.  This is a compile‑time
    // configuration flag that the compiler sets automatically.
    #[cfg(target_feature = "sse2")]
    let sse2_supported = true;
    #[cfg(not(target_feature = "sse2"))]
    let sse2_supported = false;

    // The asm! block contains two "nop" instructions.  The second one is
    // guarded by #[cfg(target_feature = "sse2")], so it will only be
    // assembled when the target has SSE2 support.  The first "nop" is
    // unconditional.
    unsafe {
        asm!(
            "nop",                     // always emitted
            #[cfg(target_feature = "sse2")]
            "nop",                     // emitted only if SSE2 is available
        );
    }

    println!(
        "SSE2 support detected at compile time: {}",
        sse2_supported
    );
}