re PR tree-optimization/27332 (ICE in try_interchange_loops with -ftree-loop-linear)

	PR middle-end/27332
	* tree-loop-linear.c (try_interchange_loops): Test for 
	no data dependences.

From-SVN: r113856

gcc/ChangeLog

+2006-05-17  Sebastian Pop  <pop@cri.ensmp.fr>
+
+	PR middle-end/27332
+	* tree-loop-linear.c (try_interchange_loops): Test for 
+	no data dependences.
+
 2006-05-17  Zdenek Dvorak <dvorakz@suse.cz>
 
 	PR tree-optimization/27548

gcc/tree-loop-linear.c

@@ -178,6 +178,9 @@ try_interchange_loops (lambda_trans_matrix trans,
   unsigned int nb_deps_not_carried_by_i, nb_deps_not_carried_by_j;
   struct data_dependence_relation *ddr;
 
+  if (VEC_length (ddr_p, dependence_relations) == 0)
+    return trans;
+
   /* When there is an unknown relation in the dependence_relations, we
      know that it is no worth looking at this loop nest: give up.  */
   ddr = VEC_index (ddr_p, dependence_relations, 0);