Re: Fortran aliasing in tree-ssa-alias.c (may_alias_p).

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

Diego Novillo wrote:

> On 03/11/06 07:51, Toon Moene wrote:
>
> > 	* tree-ssa-alias.c (may_alias_p): if -fargument-noalias-global > 1,
> > 	a pointer argument may not point to anything else.
>
> Well, that's not what the documentation states.  The pointer could be
> made to point to a local stack variable in the body of the function.  I
> realize that this may not happen in Fortran, but we are in a
> language-independent region of the code here.
>
> I would propose adding flag_argument_noalias == 3 to convey what Fortran
> guarantees: Pointer arguments that cannot point to globals nor locals.
> Then you can do:

Hmmm, perhaps I should've read the documentation, instead of trying to 
remember what John Carr meant when he invented this flag :-)

Obviously (to me, I was there when it happened) flag_argument_noalias == 
2 meant "Fortran aliasing".

However, you're right that it's not covered by the documentation.  In 
fact, you perfectly describe my "Plan B", in case this objection came up :-)

I'll dig into this - thanks for the review.

--
Toon Moene - e-mail: toon@moene.indiv.nluug.nl - phone: +31 346 214290
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A maintainer of GNU Fortran 95: http://gcc.gnu.org/fortran/
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