Re: gcc-2.7.2.3 warnings [PATCH]

From: Linus Torvalds (torvalds@transmeta.com)
Date: Fri Jul 14 2000 - 17:13:17 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?

(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).

If it makes any difference, I'd be inclined to just make gcc-2.7.2 a
compiler non grata..

                Linus

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