Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog	(revision 162447)
+++ gcc/testsuite/ChangeLog	(working copy)
@@ -1,3 +1,8 @@
+2010-07-23  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/45019
+	* gfortran.dg/aliasing_dummy_5.f90: New.
+
 2010-07-22  Jakub Jelinek  <jakub@redhat.com>
 
 	Backport from mainline
Index: gcc/testsuite/gfortran.dg/aliasing_dummy_5.f90
===================================================================
--- gcc/testsuite/gfortran.dg/aliasing_dummy_5.f90	(revision 0)
+++ gcc/testsuite/gfortran.dg/aliasing_dummy_5.f90	(revision 0)
@@ -0,0 +1,55 @@
+! { dg-do run }
+! 
+! PR fortran/45019
+!
+! Check that the compiler knows that
+! "arg" and "arr" can alias.
+!
+MODULE m
+  IMPLICIT NONE
+  INTEGER, TARGET :: arr(3)
+CONTAINS
+  SUBROUTINE foobar (arg)
+    INTEGER, TARGET :: arg(:)
+    arr(2:3) = arg(1:2)
+  END SUBROUTINE foobar
+END MODULE m
+
+PROGRAM main
+  USE m
+  IMPLICIT NONE
+  arr = (/ 1, 2, 3 /)
+  CALL bar(arr)
+  if (any (arr /= (/ 1, 1, 2 /))) call abort()
+  CALL test()
+contains
+  subroutine bar(x)
+    INTEGER, TARGET :: x(:)
+    CALL foobar (x)
+  end subroutine bar
+END PROGRAM main
+
+MODULE m2
+  IMPLICIT NONE
+  INTEGER, TARGET :: arr(3)
+CONTAINS
+   SUBROUTINE foobar (arg)
+    INTEGER, TARGET :: arg(:)
+    arr(1) = 5
+    arg(1) = 6
+!    if (arr(1) == 5) stop '2' ! FIXME: This does not work with GCC 4.4
+  END SUBROUTINE foobar
+END MODULE m2
+subroutine test
+  USE m2
+  IMPLICIT NONE
+  arr = (/ 1, 2, 3 /)
+  CALL bar(arr)
+contains
+   subroutine bar(x)
+    INTEGER, TARGET :: x(:)
+    CALL foobar (x)
+  end subroutine bar
+END subroutine test
+
+! { dg-final { cleanup-modules "m m2" } }
Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c	(revision 162447)
+++ gcc/fortran/symbol.c	(working copy)
@@ -2673,6 +2673,17 @@ gfc_symbols_could_alias (gfc_symbol *lsy
   if (lsym->attr.allocatable && rsym->attr.pointer)
     return 1;
 
+  /* Special case: Argument association, cf. F90 12.4.1.6, F2003 12.4.1.7
+     and F2008 12.5.2.13 items 3b and 4b. The pointer case (a) is already
+     checked above.  */
+  if (lsym->attr.target && rsym->attr.target
+      && ((lsym->attr.dummy
+	   && (!lsym->attr.dimension || lsym->as->type == AS_ASSUMED_SHAPE))
+	  || (rsym->attr.dummy
+	      && (!rsym->attr.dimension
+		  || rsym->as->type == AS_ASSUMED_SHAPE))))
+    return 1;
+
   return 0;
 }
 
Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog	(revision 162447)
+++ gcc/fortran/ChangeLog	(working copy)
@@ -1,3 +1,9 @@
+2010-07-23  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/45019
+	* dependency.c (gfc_check_dependency): Add argument alising check.
+	* symbol.c (gfc_symbols_could_alias): Add argument alising check.
+
 2010-07-10  Paul Thomas  <pault@gcc.gnu.org>
 
 	PR fortran/44582
Index: gcc/fortran/dependency.c
===================================================================
--- gcc/fortran/dependency.c	(revision 162447)
+++ gcc/fortran/dependency.c	(working copy)
@@ -727,6 +727,19 @@ gfc_check_dependency (gfc_expr *expr1, g
 	  /* TODO: -fassume-no-pointer-aliasing */
 	  if (gfc_is_data_pointer (expr1) || gfc_is_data_pointer (expr2))
 	    return 1;
+	  else
+	    {
+	      gfc_symbol *sym1 = expr1->symtree->n.sym;
+	      gfc_symbol *sym2 = expr2->symtree->n.sym;
+	      if (sym1->attr.target && sym2->attr.target
+		  && ((sym1->attr.dummy
+		       && (!sym1->attr.dimension
+		           || sym2->as->type == AS_ASSUMED_SHAPE))
+		      || (sym2->attr.dummy
+			  && (!sym2->attr.dimension
+			      || sym2->as->type == AS_ASSUMED_SHAPE))))
+		return 1;
+	    }
 
 	  /* Otherwise distinct symbols have no dependencies.  */
 	  return 0;