http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47001
Ira Rosen irar at il dot ibm.com changed:
What|Removed |Added
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed||2010.12.20 09:00:13
CC||irar at il dot ibm.com
AssignedTo|unassigned at gcc dot |irar at gcc dot gnu.org
|gnu.org |
Ever Confirmed|0 |1
--- Comment #1 from Ira Rosen irar at il dot ibm.com 2010-12-20 09:00:13 UTC
---
The vectorizer tries to do SLP for reduction here, but there is only one scalar
load for both reductions, which is not supported, but also is not checked. I am
testing a patch that adds such check.
Index: tree-vect-slp.c
===
--- tree-vect-slp.c (revision 167365)
+++ tree-vect-slp.c (working copy)
@@ -1002,7 +1002,35 @@ vect_supported_load_permutation_p (slp_i
if (!bad_permutation)
{
- /* This permutaion is valid for reduction. Since the order of the
+ /* Check that all the loads are different. */
+ load_index = sbitmap_alloc (group_size);
+ sbitmap_zero (load_index);
+ for (k = 0; k group_size; k++)
+{
+ first_group_load_index = VEC_index (int, load_permutation, k);
+ if (TEST_BIT (load_index, first_group_load_index))
+{
+ bad_permutation = true;
+ break;
+}
+
+ SET_BIT (load_index, first_group_load_index);
+}
+
+ if (!bad_permutation)
+for (k = 0; k group_size; k++)
+ if (!TEST_BIT (load_index, k))
+{
+ bad_permutation = true;
+ break;
+}
+
+ sbitmap_free (load_index);
+}
+
+ if (!bad_permutation)
+{
+ /* This permutation is valid for reduction. Since the order of the
statements in the nodes is not important unless they are memory
accesses, we can rearrange the statements in all the nodes
according to the order of the loads. */
Ira
