Re: gcc-2.7.2.3 warnings [PATCH] (fwd)

From: Andrzej Krzysztofowicz (ankry@green.mif.pg.gda.pl)
Date: Sat Jul 15 2000 - 08:37:04 EST


>
> On Fri, 14 Jul 2000, Andrzej Krzysztofowicz wrote:
> >
> > gcc 2.7.2.3 causes a lot of warnings when used for kernel compilation (x86)
> > with CONFIG_HIGHMEM64G=y .
> > Are the warnings meaningless ? Or kernel miscompilation may appear ?
>
> As far as I can tell, this looks like a gcc bug.
>
> Those warnings do not make sense, nor do they appear with the gcc-2.91.66
> compiler I am using.
>
> PTE_MASK is already defined to be of type "unsigned long long" (if
> CONFIG_HIGHMEM64G is set), and that type should get propagated by the
> binary "or" operator to the whole expression. Adding another explicit cast
> to the expression looks unnecessary and wrong.
>
> Does the thing make any difference to the generated code?

There is no difference in code generated by gcc-2.7.2.3.

As you suggested, the warnings are possibly a gcc bug.
However they look ugly and appear after each file compilation...

> (I would suggest doing a
>
> make mm/mprotect.s
>
> with, and without, the change, and just doing a "diff -u" on the generated
> .s files to see if there is any difference).

Regards
   Andrzej

-- 
=======================================================================
  Andrzej M. Krzysztofowicz               ankry@mif.pg.gda.pl
  phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math.,   Technical University of Gdansk

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