dependency.c (gfc_check_dependency): Implement dependency checking for array constructors.

	* dependency.c (gfc_check_dependency) <EXPR_ARRAY>: Implement
	dependency checking for array constructors.

	* gfortran.dg/dependency_20.f90: New test case.

From-SVN: r121490

gcc/fortran/ChangeLog

 2007-02-01  Roger Sayle  <roger@eyesopen.com>
 
+	* dependency.c (gfc_check_dependency) <EXPR_ARRAY>: Implement
+	dependency checking for array constructors.
+
+2007-02-01  Roger Sayle  <roger@eyesopen.com>
+
 	* trans-stmt.c (compute_overall_iter_number): Document function
 	arguments.  Generalize "unconditional forall nest with constant
 	bounds" optimization to eliminate unconditional inner loops with

gcc/fortran/dependency.c

@@ -599,9 +599,10 @@ gfc_are_equivalenced_arrays (gfc_expr *e1, gfc_expr *e2)
 int
 gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
 {
+  gfc_actual_arglist *actual;
+  gfc_constructor *c;
   gfc_ref *ref;
   int n;
-  gfc_actual_arglist *actual;
 
   gcc_assert (expr1->expr_type == EXPR_VARIABLE);
 
@@ -685,8 +686,19 @@ gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
       return 0;
 
     case EXPR_ARRAY:
-      /* Probably ok in the majority of (constant) cases.  */
-      return 1;
+      /* Loop through the array constructor's elements.  */
+      for (c = expr2->value.constructor; c; c = c->next)
+	{
+	  /* If this is an iterator, assume the worst.  */
+	  if (c->iterator)
+	    return 1;
+	  /* Avoid recursion in the common case.  */
+	  if (c->expr->expr_type == EXPR_CONSTANT)
+	    continue;
+	  if (gfc_check_dependency (expr1, c->expr, 1))
+	    return 1;
+	}
+      return 0;
 
     default:
       return 1;

gcc/testsuite/ChangeLog

+2007-02-01  Roger Sayle  <roger@eyesopen.com>
+
+	* gfortran.dg/dependency_20.f90: New test case.
+
 2007-01-31  Ian Lance Taylor  <iant@google.com>
 
 	* gcc.dg/lower-subreg-1.c (test): New test.

gcc/testsuite/gfortran.dg/dependency_20.f90

+! { dg-do compile }
+! { dg-options "-O2 -fdump-tree-original" }
+  integer :: a(4)
+
+  where (a(:) .ne. 0)
+    a(:) = (/ 1, 2, 3, 4 /)
+  endwhere
+end
+! { dg-final { scan-tree-dump-times "temp" 0 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }