The test case can be further compressed to a 3-liner

procedure( up ) :: p
call p
end

and is fixed by the following simple patch

Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 142171)
+++ gcc/fortran/resolve.c	(working copy)
@@ -2748,7 +2748,8 @@ resolve_specific_s0 (gfc_code *c, gfc_sy
 
   /* See if we have an intrinsic interface.  */
   if (sym->ts.interface != NULL && !sym->ts.interface->attr.abstract
-      && !sym->ts.interface->attr.subroutine)
+      && !sym->ts.interface->attr.subroutine
+      && sym->ts.interface->attr.intrinsic)
     {
       gfc_intrinsic_sym *isym;

I also tried to compile the other procptr examples from the WikiBooks page, which is linked in comment #0.

The only remaining problem I found was:

program bsp
  implicit none   

  abstract interface
    subroutine up()
    end subroutine up
  end interface

  procedure( up ) , pointer :: pptr

  pptr => add  
     
  contains
    
    function add( a, b )
      integer               :: add
      integer, intent( in ) :: a, b
      add = a + b
    end function add

end program bsp

This is currently accepted by gfortran, although invalid, and is rejected e.g. by ifort with

error #8179: The procedure pointer and the procedure target must both be functions or subroutines.

Inserting a statement like

  print *, pptr()

produces an ICE.

Subject: Bug 38290

Author: janus
Date: Sat Nov 29 13:36:35 2008
New Revision: 142276

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142276
Log:
2008-11-29  Janus Weil  <janus@gcc.gnu.org>
	    Mikael Morin <mikael@gcc.gnu.org>

	PR fortran/38289
	PR fortran/38290
	* decl.c (match_procedure_decl): Handle whitespaces.
	* resolve.c (resolve_specific_s0): Bugfix in check for intrinsic
	interface.


2008-11-29  Janus Weil  <janus@gcc.gnu.org>
	    Tobias Burnus <burnus@gcc.gnu.org>

	PR fortran/38289
	PR fortran/38290
	* gfortran.dg/proc_decl_1.f90: Extended test case.

Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/decl.c
    trunk/gcc/fortran/resolve.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/proc_decl_1.f90

Subject: Bug 38290

Author: janus
Date: Tue Dec  2 11:58:16 2008
New Revision: 142351

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=142351
Log:
2008-12-02  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/36704
	PR fortran/38290
	* decl.c (match_result): Result may be a standard variable or a
	procedure pointer.
	* expr.c (gfc_check_pointer_assign): Additional checks for procedure
	pointer assignments.
	* primary.c (gfc_match_rvalue): Bugfix for procedure pointer
	assignments.
	* resolve.c (resolve_function): Check for attr.subroutine.
	* symbol.c (check_conflict): Addtional checks for RESULT statements.
	* trans-types.c (gfc_sym_type,gfc_get_function_type): Support procedure
	pointers as function result.


2008-12-02  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/36704
	PR fortran/38290
	* gfortran.dg/entry_7.f90: Modified.
	* gfortran.dg/proc_ptr_2.f90: Extended.
	* gfortran.dg/proc_ptr_3.f90: Modified.
	* gfortran.dg/proc_ptr_11.f90: New.
	* gfortran.dg/proc_ptr_12.f90: New.
	* gfortran.dg/result_1.f90: New.

Added:
    trunk/gcc/testsuite/gfortran.dg/proc_ptr_11.f90
    trunk/gcc/testsuite/gfortran.dg/proc_ptr_12.f90
    trunk/gcc/testsuite/gfortran.dg/result_1.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/decl.c
    trunk/gcc/fortran/expr.c
    trunk/gcc/fortran/primary.c
    trunk/gcc/fortran/resolve.c
    trunk/gcc/fortran/symbol.c
    trunk/gcc/fortran/trans-types.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/entry_7.f90
    trunk/gcc/testsuite/gfortran.dg/proc_ptr_2.f90
    trunk/gcc/testsuite/gfortran.dg/proc_ptr_3.f90

Fixed with r142351. Closing.

Reopening. The check for comparing the interfaces was taken out again in r142520, since there were problems with intrinsics. Details will follow.

Check backed out in PR 38415, cf.
http://gcc.gnu.org/ml/fortran/2008-12/msg00089.html

"I'm afraid I'll have to remove the gfc_compare_interfaces check in
 gfc_check_pointer_assign again, since I just noticed that it has lots
 of problems with intrinsics (both in lvalue and rvalue)"

Created attachment 16841 [details]
patch v1

Here is a draft patch which correctly copies the typespec and formal args for a PROCEDURE statement with INTRINSIC interface. It also makes gfc_compare_interfaces work with intrinsics and re-enables the interface check for procedure pointer assignments.

Stuff like the following should work now:

procedure(iabs),pointer::p1
procedure(f), pointer::p2

! valid
p1 => iabs
p2 => iabs
p1 => f
p2 => f
p2 => p1
p1 => p2

! invalid
p1 => abs
p2 => abs

contains

  integer function f(x)
    integer :: x
    f = 317
  end function

end

Patch: http://gcc.gnu.org/ml/fortran/2008-12/msg00191.html

Fixed with r145651 (I messed up the PR number in the ChangeLog entry, though). Closing.