[Bug fortran/29389] New: Statement functions are not recognized as pure when they are

[Bug fortran/29389] New: Statement functions are not recognized as pure when they are

[fxcoudert at gcc dot gnu dot org]

The F95 standard says (12.6): "A pure procedure is [...] or (4) A statement
function that references only pure functions." But gfortran doesn't like that:

$ cat a5.f90 
INTEGER :: st1,i,a(4) 
st1(i)=i*i*i 
FORALL(i=1:4) a(i)=st1(i) 
print *, a
print *, u(2)

contains
pure integer function u(x)
  integer,intent(in) :: x

  st2(i) = i*i
  u = st2(x)
end function

END 
$ gfortran a5.f90
 In file a5.f90:12

  u = st2(x)
     1
Error: Function reference to 'st2' at (1) is to a non-PURE procedure within a
PURE procedure
 In file a5.f90:3

FORALL(i=1:4) a(i)=st1(i) 
                  1
Error: reference to non-PURE function 'st1' at (1) inside a FORALL block


-- 
           Summary: Statement functions are not recognized as pure when they
                    are
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: fxcoudert at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[fxcoudert at gcc dot gnu dot org]

-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-10-08 20:47:53
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[fxcoudert at gcc dot gnu dot org]

------- Comment #1 from fxcoudert at gcc dot gnu dot org  2006-10-31 00:09 -------
Created an attachment (id=12516)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12516&action=view)
Tentative patch

This patch doesn't work :)

It's working fine except that the following code:

  implicit none
  INTEGER :: st1,i,a(4)
  st1(i)=i*i*g(i)
  !FORALL(i=1:4) a(i)=st1(i)
  print *, a
  print *, u(2)

contains

pure integer function u(x)
  integer :: st2, i
  integer,intent(in) :: x

  st2(i) = i*i
  u = st2(x)
end function

pure integer function f(x)
  integer,intent(in) :: x
  f = x
end function

integer function g(x)
  integer,intent(in) :: x
  g = x
end function
end

gives the erroneous error message:

 In file pr29389.f90:3

  st1(i)=i*i*g(i)
             1
Error: Function reference to 'g' at (1) is to a non-PURE procedure within a
PURE procedure

When the statement function is resolved, gfc_current_ns points to u. I don't
understand why.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #2 from pault at gcc dot gnu dot org  2006-12-31 07:39 -------
This is fixed by:

resolve.c:1429

static int
pure_function (gfc_expr * e, const char **name)
{
  int pure;

  /* This is the fix.  */
  if (e->expr_type == EXPR_FUNCTION
        && e->symtree->n.sym->attr.proc == PROC_ST_FUNCTION)
    return 1;

  if (e->value.function.esym)

The testcase should set i = 0 and test its value at the end of the main
program, in order to demonstrate that there are no side-effects.

Regtests OK on amd64/Cygwin_NT

Paul


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |pault at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-10-08 20:47:53         |2006-12-31 07:39:01
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #3 from pault at gcc dot gnu dot org  2007-01-15 08:16 -------
Subject: Bug 29389

Author: pault
Date: Mon Jan 15 08:16:17 2007
New Revision: 120790

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=120790
Log:
2007-01-15  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/28172
        * trans-stmt.c (gfc_trans_call): If it does not have one, get
        a backend_decl for an alternate return.

        PR fortran/29389
        * resolve.c (pure_function): Statement functions are pure. Note
        that this will have to recurse to comply fully with F95.

        PR fortran/29712
        * resolve.c (resolve_function): Only a reference to the final
        dimension of an assumed size array is an error in an inquiry
        function.

        PR fortran/30283
        * resolve.c (resolve_function): Make sure that the function
        expression has a type.

2007-01-15  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/28172
        * gfortran.dg/altreturn_4.f90: New test.

        PR fortran/29389
        * gfortran.dg/stfunc_4.f90: New test.

        PR fortran/29712
        * gfortran.dg/bound_2.f90: Reinstate commented out line.
        * gfortran.dg/initialization_1.f90: Change warning.

        PR fortran/30283
        * gfortran.dg/specification_type_resolution_2.f90: New test.


Added:
    trunk/gcc/testsuite/gfortran.dg/altreturn_4.f90
    trunk/gcc/testsuite/gfortran.dg/specification_type_resolution_2.f90
    trunk/gcc/testsuite/gfortran.dg/stfunc_4.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/resolve.c
    trunk/gcc/fortran/trans-stmt.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/bound_2.f90
    trunk/gcc/testsuite/gfortran.dg/initialization_1.f90


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #4 from pault at gcc dot gnu dot org  2007-01-15 08:19 -------

> Author: pault
> Date: Mon Jan 15 08:16:17 2007
> New Revision: 120790

As pointed out by FX on the list, this patch does not quite do it yet:

The F95 standard says (12.6): "A pure procedure is [...] or (4) A statement
function that references only pure functions." Not all statement functions are
pure. Are you sure that check ("references only pure functions") is performed
by your patch?

I'll do this asap.

Paul


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #5 from pault at gcc dot gnu dot org  2007-01-23 05:53 -------
Subject: Bug 29389

Author: pault
Date: Tue Jan 23 05:53:14 2007
New Revision: 121077

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=121077
Log:
2007-01-23  Paul Thomas  <pault@gcc.gnu.org>

        Backports from trunk

        PR fortran/28172
        * trans-stmt.c (gfc_trans_call): If it does not have one, get
        a backend_decl for an alternate return.

        PR fortran/29389
        * resolve.c (pure_function): Statement functions are pure. Note
        that this will have to recurse to comply fully with F95.

        PR fortran/29712
        * resolve.c (resolve_function): Only a reference to the final
        dimension of an assumed size array is an error in an inquiry
        function.

        PR fortran/30283
        * resolve.c (resolve_function): Make sure that the function
        expression has a type.

2007-01-23  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/28172
        * gfortran.dg/altreturn_4.f90: New test.

        PR fortran/29389
        * gfortran.dg/stfunc_4.f90: New test.

        PR fortran/29712
        * gfortran.dg/bound_2.f90: Reinstate commented out line.
        * gfortran.dg/initialization_1.f90: Change warning.

        PR fortran/30283
        * gfortran.dg/specification_type_resolution_2.f90: New test.

Added:
    branches/gcc-4_2-branch/gcc/testsuite/gfortran.dg/altreturn_4.f90
   
branches/gcc-4_2-branch/gcc/testsuite/gfortran.dg/specification_type_resolution_2.f90
    branches/gcc-4_2-branch/gcc/testsuite/gfortran.dg/stfunc_4.f90
Modified:
    branches/gcc-4_2-branch/gcc/fortran/ChangeLog
    branches/gcc-4_2-branch/gcc/fortran/resolve.c
    branches/gcc-4_2-branch/gcc/fortran/trans-stmt.c
    branches/gcc-4_2-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_2-branch/gcc/testsuite/gfortran.dg/bound_2.f90
    branches/gcc-4_2-branch/gcc/testsuite/gfortran.dg/initialization_1.f90


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #6 from pault at gcc dot gnu dot org  2007-01-23 05:56 -------
Partially fixed - see list.

Paul


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[jv244 at cam dot ac dot uk]

------- Comment #7 from jv244 at cam dot ac dot uk  2007-07-04 06:29 -------
list link: 

http://gcc.gnu.org/ml/fortran/2007-01/msg00361.html
this suggests that it is now an accepts-invalid bug with an easy fix 

(Bug reporter / assignee should change keyword)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #8 from pault at gcc dot gnu dot org  2007-11-27 20:48 -------
Subject: Bug 29389

Author: pault
Date: Tue Nov 27 20:47:55 2007
New Revision: 130472

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=130472
Log:
2007-11-27  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/29389
        *resolve.c (resolve_ordinary_assign): Use find_sym_in_expr to
        test if a temporary should be written for a vector subscript
        on the lhs.

        PR fortran/33850
        * restore.c (pure_stmt_function): Add prototype and new
        function. Calls impure_stmt_fcn.
        (pure_function): Call it.
        (impure_stmt_fcn): New function.

        * expr.c (gfc_traverse_expr): Call *func for all expression
        types, not just variables. Add traversal of character lengths,
        iterators and component character lengths and arrayspecs.
        (expr_set_symbols_referenced): Return false if not a variable.
        * trans-stmt.c (forall_replace, forall_restore): Ditto.
        * resolve.c (forall_index): Ditto.
        (sym_in_expr): New function.
        (find_sym_in_expr): Rewrite to traverse expression calling
        sym_in_expr.
        *trans-decl.c (expr_decls): New function.
        (generate_expr_decls): Rewrite to traverse expression calling
        expr_decls.
        *match.c (check_stmt_fcn): New function.
        (recursive_stmt_fcn): Rewrite to traverse expression calling
        check_stmt_fcn.

2007-11-27  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/29389
        * gfortran.dg/stfunc_6.f90: New test.

        PR fortran/33850
        * gfortran.dg/assign_10.f90: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/assign_10.f90
    trunk/gcc/testsuite/gfortran.dg/stfunc_6.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/expr.c
    trunk/gcc/fortran/match.c
    trunk/gcc/fortran/resolve.c
    trunk/gcc/fortran/trans-decl.c
    trunk/gcc/fortran/trans-stmt.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[pault at gcc dot gnu dot org]

------- Comment #9 from pault at gcc dot gnu dot org  2007-11-27 20:52 -------
Fixed on trunk

Paul


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389

[Bug fortran/29389] Statement functions are not recognized as pure when they are

[dominiq at lps dot ens dot fr]

------- Comment #10 from dominiq at lps dot ens dot fr  2008-09-06 16:58 -------
Note that before the patch for pr35837, the code in comment #1 was wrongly
rejected. This is now fixed by this patch. Also if the FORALL statement is this
code is uncommented, it is now accepted while it is invalid, see pr37398.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29389