Alexander Monakov <amonakov@xxxxxxxxx> writes:
> +/*
> + * Compiler reassociation barrier: pretend to modify X and Y to disallow
> + * changing evaluation order with respect to following uses of X and Y.
> + */
> +#ifdef __GNUC__
> +#define REASSOC_FENCE(x, y) asm("" : "+r"(x), "+r"(y))
> +#else
> +#define REASSOC_FENCE(x, y)
> +#endif
With gcc we can build, but with clang, we unfortunately get this:
$ make CC=clang DEVELOPER=YesPlease
xdiff/xutils.c:330:4: error: extension used [-Werror,-Wlanguage-extension-token]
330 | REASSOC_FENCE(c0, ha);
| ^
xdiff/xutils.c:302:29: note: expanded from macro 'REASSOC_FENCE'
302 | #define REASSOC_FENCE(x, y) asm("" : "+r"(x), "+r"(y))
| ^
