[PATCH][alias-improvements] More type-based disambiguation
Sat Jan 17 17:43:00 GMT 2009
On Sat, 17 Jan 2009, Daniel Berlin wrote:
> On Sat, Jan 17, 2009 at 11:00 AM, Richard Guenther <firstname.lastname@example.org> wrote:
> > This fixes type-based disambiguation to also consider canonical types
> > and eventual structual comparisons. I believe this allows us to enable
> > a positive fallback for disjunct access paths. It fixes the long-standing
> > PR13146 and a deficiency compared to RTL alias analysis (PR38895), but
> > without the cost of a quadratic loop.
> > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to the
> > branch.
> > Richard.
> > Index: gcc/tree-ssa-alias.c
> > ===================================================================
> > *** gcc/tree-ssa-alias.c.orig 2009-01-17 16:50:25.000000000 +0100
> > --- gcc/tree-ssa-alias.c 2009-01-17 16:50:58.000000000 +0100
> > *************** debug_points_to_info_for (tree var)
> > *** 357,362 ****
> > --- 357,380 ----
> > dump_points_to_info_for (stderr, var);
> > }
> > + /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
> > + purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
> > + decide. */
> For multi-valued functions like this, it would be nice to either
> return an enum, or at least, #define the results to names that have
> some meaning.
> It makes it much easier to understand later (and when the function
> inveitably gets exported and used all over the codebase ;P)
Heh, yeah. I'll do it.
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