Re: [PATCH v6 05/12] regmap: irq: Remove unreachable goto

Andy Shevchenko
2025-04-09T16:45:51Z

On Wed, Apr 09, 2025 at 05:32:55PM +0100, Mark Brown wrote:
> On Wed, Apr 09, 2025 at 07:00:24PM +0300, Andy Shevchenko wrote:
> > On Wed, Apr 09, 2025 at 04:46:04PM +0100, Mark Brown wrote:
>
> > > unreachable() just annotates things, AFAICT it doesn't actually
> > > guarantee to do anything in particular if the annotation turns out to be
> > > incorrect.
>
> > I;m not sure I follow. unreachable is a wrapper on top of
> > __builtin_unreachable() which is intrinsic of the compiler.
>
> > https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005funreachable
>
> That just says that the program is undefined if we get to the
> __builtin_undefined() and documents some behaviour around warnings. One
> example of undefined behaviour would be doing nothing.

Theoretically yes, practically return after a BUG() makes no sense. Note,
that compiler effectively removes 'goto exit;' here (that's also mentioned
in the documentation independently on the control flow behaviour), so
I don't know what you expect from it.

--
With Best Regards,
Andy Shevchenko