[Bug tree-optimization/42637] [4.5 Regression][graphite] wrong code for -floop-interchange -ftree-loop-distribution

["spop at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from spop at gcc dot gnu dot org  2010-01-16 22:17 -------
I have looked again to this function, and I just realized that there
were changes to one of the functions of the data dependence test:
build_pairwise_scheduling_inequality used to build strict inequalities
for the lexicographic comparison, and then Tobias changed it like this:

-    cstr = build_pairwise_constraint (dim, pos, pos + offset, 0,
PPL_CONSTRAINT_TYPE_GREATER_THAN); 
+    cstr = build_pairwise_constraint (dim, pos, pos + offset, -1,
+                                     PPL_CONSTRAINT_TYPE_GREATER_OR_EQUAL);
   else
-    cstr = build_pairwise_constraint (dim, pos, pos + offset, 0,
PPL_CONSTRAINT_TYPE_LESS_THAN); 
+    cstr = build_pairwise_constraint (dim, pos, pos + offset, 1,
+                                     PPL_CONSTRAINT_TYPE_LESS_OR_EQUAL);


This is wrong.

This change was done when we decided to remove the use of the NNC
(Non-Necessarily Closed) polyhedra into C (Closed) polyhedra, that do
not allow the strict inequalities.  I am working on a fix for this PR.

Sebastian


-- 

spop at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|trifunovic at gcc dot gnu   |spop at gcc dot gnu dot org
                   |dot org                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42637