[PATCH 2/3] arm64: Optimize __READ_ONCE() with CONFIG_LTO=y

[Arnd Bergmann]

On Mon, Jan 26, 2026, at 01:25, Marco Elver wrote:
> diff --git a/arch/arm64/include/asm/rwonce.h b/arch/arm64/include/asm/rwonce.h
> index fc0fb42b0b64..9963948f4b44 100644
> --- a/arch/arm64/include/asm/rwonce.h
> +++ b/arch/arm64/include/asm/rwonce.h
> @@ -32,8 +32,7 @@
>  #define __READ_ONCE(x)							\
>  ({									\
>  	typeof(&(x)) __x = &(x);					\
> -	int atomic = 1;							\
> -	union { __unqual_scalar_typeof(*__x) __val; char __c[1]; } __u;	\
> +	union { TYPEOF_UNQUAL(*__x) __val; char __c[1]; } __u;		\
>  	switch (sizeof(x)) {						\
>  	case 1:								\
>  		asm volatile(__LOAD_RCPC(b, %w0, %1)			\

How does this work with CC_HAS_TYPEOF_UNQUAL=false?

As far as I can tell, TYPEOF_UNQUAL() falls back to __typeof__
on gcc-13, clang-18 and earlier, and not strip out qualifiers.

With fd69b2f7d5f4 ("compiler: Use __typeof_unqual__() for
__unqual_scalar_typeof()"), I would expect __unqual_scalar_typeof()
to do the right thing already.

     Arnd