Re: linux-next: tree build failure

From: Hollis Blanchard
Date: Tue Sep 29 2009 - 19:39:44 EST


On Tue, 2009-09-29 at 10:28 +0100, Jan Beulich wrote:
> >>> Hollis Blanchard 09/29/09 2:00 AM >>>
> >First, I think there is a real bug here, and the code should read like
> >this (to match the comment):
> > /* type has to be known at build time for optimization */
> >- BUILD_BUG_ON(__builtin_constant_p(type));
> >+ BUILD_BUG_ON(!__builtin_constant_p(type));
> >
> >However, I get the same build error *both* ways, i.e.
> >__builtin_constant_p(type) evaluates to both 0 and 1? Either that, or
> >the new BUILD_BUG_ON() macro isn't working...
>
> No, at this point of the compilation process it's neither zero nor one,
> it's simply considered non-constant by the compiler at that stage
> (this builtin is used for optimization, not during parsing, and the
> error gets generated when the body of the function gets parsed,
> not when code gets generated from it).

I think I see what you're saying. Do you have a fix to suggest?

--
Hollis Blanchard
IBM Linux Technology Center

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