Re: [PATCH 11/23] make atomic_read() and atomic_set() behavior consistent on m32r

[David Howells]

Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx> wrote:

> This simply isn't true.  The compiler *can* combine asm stuff:
> 
> 
> typedef struct { int counter; } atomic_t;
> 
> static inline __attribute__((pure)) int atomic_read(const atomic_t *v)
> {
>         int x;
>         asm("ld %0,@%1" : "=r"(x) : "r"(&v->counter), "m"(v->counter));
>         return x;
> }

That's not precisely combining asm stuff.  The compiler is ditching a whole
function because you've told it it can cache the result.

David
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