re PR tree-optimization/34635 (tree check: expected polynomial_chrec, have…

re PR tree-optimization/34635 (tree check: expected polynomial_chrec, have integer_cst in add_multivariate_self_dist, at tree-data-ref.c:2813)

2007-12-19  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/34635
	* tree-data-ref.c (add_other_self_distances): Make sure that the
	evolution step is constant.

	* gcc.dg/tree-ssa/pr34635.c: New.
	* gcc.dg/tree-ssa/pr34635-1.c: New.

From-SVN: r131275

gcc/ChangeLog

+2007-12-19  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR tree-optimization/34635
+	* tree-data-ref.c (add_other_self_distances): Make sure that the
+	evolution step is constant.
+
 2008-01-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/34608

gcc/testsuite/ChangeLog

+2007-12-19  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR tree-optimization/34635
+	* gcc.dg/tree-ssa/pr34635.c: New.
+	* gcc.dg/tree-ssa/pr34635-1.c: New.
+
 2008-01-02  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	PR middle-end/34562

gcc/testsuite/gcc.dg/tree-ssa/pr34635-1.c

+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+void foo(int x[])
+{
+ int i, j;
+
+ for (i = 0; i < 2; i++)
+   for (j = 0; j < 2; j++)
+   {
+     x[i] = x[i+j];
+     x[i] = x[i+j];
+   }
+}

gcc/testsuite/gcc.dg/tree-ssa/pr34635.c

+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+void foo(int x[])
+{
+ int i, j;
+
+ for (i = 0; i < 2; i++)
+   for (j = 0; j < 2; j++)
+   {
+     x[i] = x[i*j];
+     x[i] = x[i*j];
+   }
+}

gcc/tree-data-ref.c

@@ -2818,9 +2818,9 @@ constant_access_functions (const struct data_dependence_relation *ddr)
   return true;
 }
 
-
 /* Helper function for the case where DDR_A and DDR_B are the same
-   multivariate access function.  */
+   multivariate access function with a constant step.  For an example
+   see pr34635-1.c.  */
 
 static void
 add_multivariate_self_dist (struct data_dependence_relation *ddr, tree c_2)
@@ -2890,7 +2890,17 @@ add_other_self_distances (struct data_dependence_relation *ddr)
 		  return;
 		}
 
-	      add_multivariate_self_dist (ddr, DR_ACCESS_FN (DDR_A (ddr), 0));
+	      access_fun = DR_ACCESS_FN (DDR_A (ddr), 0);
+
+	      if (TREE_CODE (CHREC_LEFT (access_fun)) == POLYNOMIAL_CHREC)
+		add_multivariate_self_dist (ddr, access_fun);
+	      else
+		/* The evolution step is not constant: it varies in
+		   the outer loop, so this cannot be represented by a
+		   distance vector.  For example in pr34635.c the
+		   evolution is {0, +, {0, +, 4}_1}_2.  */
+		DDR_AFFINE_P (ddr) = false;
+
 	      return;
 	    }