Jakub Jelinek <ja...@redhat.com> wrote on 21/11/2011 07:25:10 PM:
> From: Jakub Jelinek <ja...@redhat.com>
> To: Razya Ladelsky/Haifa/IBM@IBMIL
> Cc: GCC Patches <gcc-patches@gcc.gnu.org>, Richard Guenther
> <richard.guent...@gmail.com>
> Date: 21/11/2011 07:25 PM
> Subject: Re: [PATCH, take 2] Fix PR tree-optimization/49960 ,Fix
> self data dependence
>
> On Mon, Nov 21, 2011 at 06:56:55PM +0200, Razya Ladelsky wrote:
> > I have some non-affine cases for which compute_affine_dependence is
called
> > (as it is called for
> > ALL dependences from compte_all_depepndences()), and no harm is done.
> > I looked a little bit closer into the code, and this is what happens
for
> > non affine accesses:
> >
> > initialize_data_dependence_relation() assigns
> > DDR_ARE_DEPENDENT (res) = chrec_dont_know for the dr.
>
> It can be chrec_known too (that's actually the only interesting case for
us
> unless it is a read-read ddr), but you're right that likely
> object_address_invariant_in_loop_p should be false.
>
> > Then, compute_affine_depepndence()
> > tests if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE), and does nothing
> > otherwise.
> > Since the dr was initialized with chrec_dont_know, no harm is done.
> >
> > Anyway, since it is useless for your gather case, I'll just remove it,
> > along with compute_self_dependence().
> >
> > OK?
>
> Yes, patch preapproved.
>
> Jakub
>
Hi,
Going to commit this patch today.
I bootstrapped and regtested on ppc64-suse-linux.
ChangeLog:
* tree-data-ref.c (initialize_data_dependence_relation): Update
comment for the
self dependence case.
(compute_self_dependence): Remove.
* tree-vect-data-refs.c (vect_analyze_data_refs): Remove call to
compute_self_dependenc.
Thanks,
Razya
Index: tree-data-ref.c
===================================================================
--- tree-data-ref.c (revision 181675)
+++ tree-data-ref.c (working copy)
@@ -1385,8 +1385,7 @@ initialize_data_dependence_relation (struct data_r
return res;
}
- /* When the references are exactly the same, don't spend time doing
- the data dependence tests, just initialize the ddr and return. */
+ /* The case where the references are exactly the same. */
if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
{
if (loop_nest
@@ -4132,19 +4131,6 @@ compute_affine_dependence (struct data_dependence_
fprintf (dump_file, ")\n");
}
-/* This computes the dependence relation for the same data
- reference into DDR. */
-
-void
-compute_self_dependence (struct data_dependence_relation *ddr)
-{
- if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
- return;
-
- if (DDR_LOOP_NEST (ddr))
- compute_affine_dependence (ddr, VEC_index (loop_p, DDR_LOOP_NEST (ddr),
0));
-}
-
/* Compute in DEPENDENCE_RELATIONS the data dependence graph for all
the data references in DATAREFS, in the LOOP_NEST. When
COMPUTE_SELF_AND_RR is FALSE, don't compute read-read and self
Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c (revision 181675)
+++ tree-vect-data-refs.c (working copy)
@@ -3122,7 +3122,6 @@ vect_analyze_data_refs (loop_vec_info loop_vinfo,
ddr = VEC_index (ddr_p, ddrs, k);
gcc_assert (DDR_A (ddr) == olddr && DDR_B (ddr) == olddr);
newddr = initialize_data_dependence_relation (dr, dr, nest);
- compute_self_dependence (newddr);
VEC_replace (ddr_p, ddrs, k, newddr);
free_dependence_relation (ddr);
VEC_replace (data_reference_p, datarefs, i, dr);
=
