How to compile and test intrinsic with rustc_codegen_gcc.rs

#![feature(no_core)]
#![no_core]
#![crate_type="rlib"]
#![feature(rustc_attrs)]
#![feature(fundamental)]
#![feature(lang_items)]
#![feature(intrinsics)]
#![feature(auto_traits)]
#![allow(non_camel_case_types)]

//! How to compile with gcc
//! ```
//! export LIBRARY_PATH="/home/angel/gcc-build/gcc:/home/angel/rust/build/x86_64-unknown-linux-gnu/stage2/lib/"
//! export LD_LIBRARY_PATH="/home/angel/gcc-build/gcc:/home/angel/rust/build/x86_64-unknown-linux-gnu/stage2/lib/"
//! rustc +stage2 -Copt-level=3 \
//!     -Z force-unstable-if-unmarked -Zcodegen-backend=/home/angel/rust/compiler/rustc_codegen_gcc/target/debug/librustc_codegen_gcc.so \
//!     --sysroot /home/angel/rust/compiler/rustc_codegen_gcc/build_sysroot/sysroot \
//!     test_many_swaps.rs --emit=asm
//! ```
//!

#[repr(align(64))]
pub struct BigButHighlyAligned([u8; 192]);

#[no_mangle]
pub fn swap_BigButHighlyAligned(a: &mut BigButHighlyAligned, b: &mut BigButHighlyAligned){
    swap_nonoverlapping(a, b);
}

pub struct A_0([u8; 0]);
pub struct A_1([u8; 1]);
pub struct A_2([u8; 2]);
pub struct A_3([u8; 3]);
pub struct A_4([u8; 4]);
pub struct A_5([u8; 5]);
pub struct A_6([u8; 6]);
pub struct A_7([u8; 7]);
pub struct A_8([u8; 8]);
pub struct A_9([u8; 9]);
pub struct A_10([u8; 10]);
pub struct A_11([u8; 11]);
pub struct A_12([u8; 12]);
pub struct A_13([u8; 13]);
pub struct A_14([u8; 14]);
pub struct A_15([u8; 15]);
pub struct A_16([u8; 16]);

#[no_mangle]
pub fn swap_a_0(a: &mut A_0, b: &mut A_0){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_1(a: &mut A_1, b: &mut A_1){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_2(a: &mut A_2, b: &mut A_2){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_3(a: &mut A_3, b: &mut A_3){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_4(a: &mut A_4, b: &mut A_4){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_5(a: &mut A_5, b: &mut A_5){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_6(a: &mut A_6, b: &mut A_6){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_7(a: &mut A_7, b: &mut A_7){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_8(a: &mut A_8, b: &mut A_8){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_9(a: &mut A_9, b: &mut A_9){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_10(a: &mut A_10, b: &mut A_10){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_11(a: &mut A_11, b: &mut A_11){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_12(a: &mut A_12, b: &mut A_12){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_13(a: &mut A_13, b: &mut A_13){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_14(a: &mut A_14, b: &mut A_14){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_15(a: &mut A_15, b: &mut A_15){
 swap_nonoverlapping(a, b);
}
#[no_mangle]
pub fn swap_a_16(a: &mut A_16, b: &mut A_16){
 swap_nonoverlapping(a, b);
}

#[doc(alias = "?", alias = "?Sized")]
#[lang = "sized"]
#[rustc_on_unimplemented(
    message = "the size for values of type `{Self}` cannot be known at compilation time",
    label = "doesn't have a size known at compile-time"
)]
#[fundamental]
#[rustc_specialization_trait]
#[rustc_deny_explicit_impl]
#[rustc_coinductive]
pub trait Sized {
    // Empty.
}

#[lang = "copy"]
#[rustc_unsafe_specialization_marker]
#[rustc_diagnostic_item = "Copy"]
pub trait Copy: Clone {
    // Empty.
}
#[lang = "clone"]
#[rustc_diagnostic_item = "Clone"]
#[rustc_trivial_field_reads]
pub trait Clone: Sized {}

#[inline]
#[rustc_nounwind]
pub fn swap_nonoverlapping<T: Sized>(x: &mut T, y: &mut T) {
    extern "rust-intrinsic" {
        #[rustc_nounwind]
        fn swap_nonoverlapping_single<T: Sized>(x: *mut T, y: *mut T);
    }
    unsafe {
        swap_nonoverlapping_single(x as *mut T, y as *mut T);
    }
}

#[rustc_on_unimplemented(
    note = "consider using the `pin!` macro\nconsider using `Box::pin` if you need to access the pinned value outside of the current scope",
    message = "`{Self}` cannot be unpinned"
)]
#[lang = "unpin"]
pub auto trait Unpin {}