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From: Kyle Evans <kevans@freebsd.org>
Date: Wed, 19 Feb 2020 16:57:19 -0600
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Subject: Re: svn commit: r358133 - head/sys/vm
To: Joerg Sonnenberger <joerg@bec.de>
Cc: Jeff Roberson <jeff@freebsd.org>,
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On Wed, Feb 19, 2020 at 4:49 PM Joerg Sonnenberger <joerg@bec.de> wrote:
>
> On Wed, Feb 19, 2020 at 10:34:23PM +0000, Jeff Roberson wrote:
> > Author: jeff
> > Date: Wed Feb 19 22:34:22 2020
> > New Revision: 358133
> > URL: https://svnweb.freebsd.org/changeset/base/358133
> >
> > Log:
> >   Silence a gcc warning about no return from a function that handles every
> >   possible enum in a switch statement.  I verified that this emits nothing
> >   as expected on clang.  radix relies on constant propagation to eliminate
> >   any branching from these access routines.
>
> __builtin_unreachable() ?
>

We seem to call that __unreachable() to address compilers where it may
not be defined, but it does seem to be the ideal way to handle it.