Re: [GIT PULL] core kernel fixes

[Josh Poimboeuf]

On Sun, Nov 05, 2017 at 12:12:31PM -0800, Linus Torvalds wrote:
> On Sun, Nov 5, 2017 at 11:53 AM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >
> > The GCC manual says:
> >
> >   "asm statements that have no output operands, including asm goto
> >    statements, are implicitly volatile."
> 
> Hmm. Fair enough.
> 
> And the manual does say that it can merge and duplicate those asms
> (and suggests using "%=" to generate a unique number, but I guess
> "%c0" with __COUNTER__ is equivalent).
> 
> I think the gcc manual has changed. I'm pretty certain it used to say
> that "volatile" asms would not be "moved significantly". They've
> silently changed semantics before too, oh well.

I had tried the '%=' thing before, because that was exactly what I
needed.  But alas, it's not supported by the older GCCs.

-- 
Josh