diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fcd2c2e1202..31ab14bab86 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-03-15  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/52580
+	* tree-data-ref.c (subscript_dependence_tester_1): Check
+	all dimensions for non-conflicting access functions.
+
 2012-03-15  Manuel López-Ibáñez  <manu@gcc.gnu.org>
 
 	PR c++/44783
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9d57d21fcd7..d39995fb44b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-15  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/52580
+	* gfortran.dg/vect/pr52580.f: New testcase.
+
 2012-03-15  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	* gcc.target/sh/fpul-usage-1.c: New.
diff --git a/gcc/testsuite/gfortran.dg/vect/pr52580.f b/gcc/testsuite/gfortran.dg/vect/pr52580.f
new file mode 100644
index 00000000000..eab9fa54bf5
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/vect/pr52580.f
@@ -0,0 +1,33 @@
+! { dg-do compile }
+! { dg-require-effective-target vect_double }
+      SUBROUTINE CALC2
+      IMPLICIT REAL*8	(A-H, O-Z)
+      PARAMETER (N1=1335, N2=1335)
+
+      COMMON  U(N1,N2), V(N1,N2), P(N1,N2),
+     *        UNEW(N1,N2), VNEW(N1,N2),
+     1        PNEW(N1,N2), UOLD(N1,N2),
+     *        VOLD(N1,N2), POLD(N1,N2),
+     2        CU(N1,N2), CV(N1,N2),
+     *        Z(N1,N2), H(N1,N2), PSI(N1,N2)
+      COMMON /CONS/ DT,TDT,DX,DY,A,ALPHA,ITMAX,MPRINT,M,N,MP1,
+     1              NP1,EL,PI,TPI,DI,DJ,PCF
+      TDTS8 = TDT/8.D0
+      TDTSDX = TDT/DX
+      TDTSDY = TDT/DY
+
+      DO 200 J=1,N
+      DO 200 I=1,M
+      UNEW(I+1,J) = UOLD(I+1,J)+
+     1    TDTS8*(Z(I+1,J+1)+Z(I+1,J))*(CV(I+1,J+1)+CV(I,J+1)+CV(I,J)
+     2       +CV(I+1,J))-TDTSDX*(H(I+1,J)-H(I,J))
+      VNEW(I,J+1) = VOLD(I,J+1)-TDTS8*(Z(I+1,J+1)+Z(I,J+1))
+     1       *(CU(I+1,J+1)+CU(I,J+1)+CU(I,J)+CU(I+1,J))
+     2       -TDTSDY*(H(I,J+1)-H(I,J))
+      PNEW(I,J) = POLD(I,J)-TDTSDX*(CU(I+1,J)-CU(I,J))
+     1       -TDTSDY*(CV(I,J+1)-CV(I,J))
+  200 CONTINUE
+      RETURN
+      END
+! { dg-final { scan-tree-dump-times "LOOP VECTORIZED" 1 "vect" } }
+! { dg-final { cleanup-tree-dump "vect" } }
diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index e7bb16fcbc2..9b3a10df3c7 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -3460,6 +3460,7 @@ subscript_dependence_tester_1 (struct data_dependence_relation *ddr,
   unsigned int i;
   tree last_conflicts;
   struct subscript *subscript;
+  tree res = NULL_TREE;
 
   for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
        i++)
@@ -3471,40 +3472,43 @@ subscript_dependence_tester_1 (struct data_dependence_relation *ddr,
 				      &overlaps_a, &overlaps_b,
 				      &last_conflicts, loop_nest);
 
+      if (SUB_CONFLICTS_IN_A (subscript))
+	free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
+      if (SUB_CONFLICTS_IN_B (subscript))
+	free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
+
+      SUB_CONFLICTS_IN_A (subscript) = overlaps_a;
+      SUB_CONFLICTS_IN_B (subscript) = overlaps_b;
+      SUB_LAST_CONFLICT (subscript) = last_conflicts;
+
+      /* If there is any undetermined conflict function we have to
+         give a conservative answer in case we cannot prove that
+	 no dependence exists when analyzing another subscript.  */
       if (CF_NOT_KNOWN_P (overlaps_a)
  	  || CF_NOT_KNOWN_P (overlaps_b))
  	{
- 	  finalize_ddr_dependent (ddr, chrec_dont_know);
-	  dependence_stats.num_dependence_undetermined++;
-	  free_conflict_function (overlaps_a);
-	  free_conflict_function (overlaps_b);
-	  return false;
+	  res = chrec_dont_know;
+	  continue;
  	}
 
+      /* When there is a subscript with no dependence we can stop.  */
       else if (CF_NO_DEPENDENCE_P (overlaps_a)
  	       || CF_NO_DEPENDENCE_P (overlaps_b))
  	{
- 	  finalize_ddr_dependent (ddr, chrec_known);
-	  dependence_stats.num_dependence_independent++;
-	  free_conflict_function (overlaps_a);
-	  free_conflict_function (overlaps_b);
-	  return false;
- 	}
-
-      else
- 	{
-	  if (SUB_CONFLICTS_IN_A (subscript))
-	    free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
-	  if (SUB_CONFLICTS_IN_B (subscript))
-	    free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
-
- 	  SUB_CONFLICTS_IN_A (subscript) = overlaps_a;
- 	  SUB_CONFLICTS_IN_B (subscript) = overlaps_b;
-	  SUB_LAST_CONFLICT (subscript) = last_conflicts;
+	  res = chrec_known;
+	  break;
  	}
     }
 
-  return true;
+  if (res == NULL_TREE)
+    return true;
+
+  if (res == chrec_known)
+    dependence_stats.num_dependence_independent++;
+  else
+    dependence_stats.num_dependence_undetermined++;
+  finalize_ddr_dependent (ddr, res);
+  return false;
 }
 
 /* Computes the conflicting iterations in LOOP_NEST, and initialize DDR.  */