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Re: Aliasing violation generated by fold_builtin_memcmp?
On Fri, 2005-09-30 at 11:23 +0200, Olivier Hainque wrote:
> Richard Henderson wrote:
> > Try
> >
> > cst_uchar_ptr_node
> > = build_pointer_type_for_mode (cst_uchar_node, ptr_mode, true);
> >
> > which is apparently in use by the Ada front end, but only if a
> > certain pragma is given. Dunno how reliably that's likely to work.
>
> We are seeing regressions in our local testsuite on cases exercising
> that pragma.
>
> Passing 'true' as CAN_ALIAS_ALL sets TYPE_REF_CAN_ALIAS_ALL (t), but
> this apparently has no influence on what tree-ssa-alias computes.
>
> Out of a preliminary look into this code (new to me), a possible place
> to address that appears to be 'get_tmt_for', which presumably should assign
> a zero alias set to tags for pointer types with that bit set.
Actually, you just want it to assign the same tag, not change the alias
set of every tag it assigns.