tree-data-ref.c (build_classic_dist_vector): If either loop is outside of the…

tree-data-ref.c (build_classic_dist_vector): If either loop is outside of the nest we asked about, the dependence can't matter.

2004-11-10  Daniel Berlin  <dberlin@dberlin.org>

	* tree-data-ref.c (build_classic_dist_vector): If either loop
	is outside of the nest we asked about, the dependence can't
	matter.
	(build_classic_dir_vector): Ditto.

From-SVN: r90454

gcc/ChangeLog

+2004-11-10  Daniel Berlin  <dberlin@dberlin.org>
+
+	* tree-data-ref.c (build_classic_dist_vector): If either loop
+	is outside of the nest we asked about, the dependence can't
+	matter.	
+	(build_classic_dir_vector): Ditto.
+
 2004-11-10  Zdenek Dvorak  <dvorakz@suse.cz>
 
 	* tree-ssa-loop-ivopts.c (get_address_cost): Add address elements in

gcc/testsuite/gcc.dg/tree-ssa/20041110-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-loop-linear" } */
+
+/* This testcase was causing an ICE in building distance vectors because
+   we weren't ignoring the fact that one of the induction variables
+   involved in the dependence was outside of the loop.  */
+extern int foo (int, int);
+int
+main (void)
+{
+  int a[50];
+  int b[50];
+  int i, j, k;
+  for (i = 4; i < 30; i++)
+    {
+      for (j = 3; j < 40; j++)
+	{
+	  for (k = 9; k < 50; k++)
+	    {
+	      b[j] = a[i];
+	      a[k] = b[i];
+	    }
+	}
+    }
+  foo (a[i], b[i]);
+}

gcc/tree-data-ref.c

@@ -1816,12 +1816,12 @@ build_classic_dist_vector (struct data_dependence_relation *ddr,
 	  struct loop *loop_b = current_loops->parray[loop_nb_b];
 	  struct loop *loop_first = current_loops->parray[first_loop];
 
-	  /* If the loops for both variables are at a lower depth than 
-	     the first_loop's depth, then they can't possibly have a
+	  /* If the loop for either variable is at a lower depth than 
+	     the first_loop's depth, then we can't possibly have a
 	     dependency at this level of the loop.  */
 	     
 	  if (loop_a->depth < loop_first->depth
-	      && loop_b->depth < loop_first->depth)
+	      || loop_b->depth < loop_first->depth)
 	    return false;
 
 	  if (loop_nb_a != loop_nb_b
@@ -1992,11 +1992,12 @@ build_classic_dir_vector (struct data_dependence_relation *ddr,
 	  struct loop *loop_b = current_loops->parray[loop_nb_b];
 	  struct loop *loop_first = current_loops->parray[first_loop];
  
-	  /* If the loops for both variables are at a lower depth than 
-	     the first_loop's depth, then they can't possibly matter */
+	  /* If the loop for either variable is at a lower depth than 
+	     the first_loop's depth, then we can't possibly have a
+	     dependency at this level of the loop.  */
 	     
 	  if (loop_a->depth < loop_first->depth
-	      && loop_b->depth < loop_first->depth)
+	      || loop_b->depth < loop_first->depth)
 	    return false;
 
 	  if (loop_nb_a != loop_nb_b