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Re: RFC: [PATCH]: PR31806 - Fix MEM_READONLY_P aliasing disambiguation

On 5/30/07, Richard Guenther <richard.guenther@gmail.com> wrote: 
>
> Any comments?

I think those mems should not be MEM_READONLY_P if they are written to
(if not the program is invalid).  Of course the patch is a reasonable
workaround for
the branches if the "real" fix is too invasive.  I suppose the
frontend(s) set this
bit?


I mentioned the same thing in the bug report and pointed to another
bug report where the front-end messes up TREE_READONLY (PR 31809).
MEM_READONLY_P is set from TREE_READONLY:
     if (base && DECL_P (base)
         && TREE_READONLY (base)
         && (TREE_STATIC (base) || DECL_EXTERNAL (base)))
       {
         tree base_type = TREE_TYPE (base);
         gcc_assert (!(base_type && TYPE_NEEDS_CONSTRUCTING (base_type))
                     || DECL_ARTIFICIAL (base));
         MEM_READONLY_P (ref) = 1;
       }


So the real issue is the C++ front-end is setting TREE_READONLY to
true when it should not (exactly the same as PR 31809).

Thanks,
Andrew Pinski

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