Ping**2! Re: [PATCH, Fortran] Extension: AUTOMATIC/STATIC symbol attributes with -fdec-static

Ping**2! Re: [PATCH, Fortran] Extension: AUTOMATIC/STATIC symbol attributes with -fdec-static

[Fritz Reese]

https://gcc.gnu.org/ml/fortran/2016-08/msg00173.html
On Mon, Aug 29, 2016 at 8:36 AM, Fritz Reese <fritzoreese@gmail.com> wrote:
>
> https://gcc.gnu.org/ml/fortran/2016-08/msg00077.html
> On Wed, Aug 17, 2016 at 7:20 AM, Fritz Reese <fritzoreese@gmail.com> wrote:
> > This patch extends the GNU Fortran front-end to add support for
> > DEC-style AUTOMATIC and STATIC symbol attributes with a new flag
> > -fdec-static, allowing explicit control of variable storage. AUTOMATIC
> > local variables are placed on the stack, whereas STATIC variables are
> > placed in static storage.
>
> Patch still pending review.
>
> > Bootstraps and regtests on x86_64-redhat-linux. Questions, comments,
> > and critique welcome. Ok for trunk?
> ...
> >
> > 08-17-2016  Fritz Reese  <fritzoreese@gmail.com>
> >
> >     gcc/fortran/
> >         * lang.opt, invoke.texi, gfortran.texi: New flag -fdec-static.
> >             * options.c (set_dec_flags): Set -fdec-static with -fdec.
> >         * gfortran.h (symbol_attribute): New attribute AUTOMATIC.
> >         * gfortran.h (gfc_add_automatic): New prototype.
> >         * match.h (gfc_match_automatic, gfc_match_static): New functions.
> >         * decl.c (gfc_match_automatic, gfc_match_static): Ditto.
> >         * symbol.c (gfc_add_automatic): Ditto.
> >         * decl.c (match_attr_spec): Match AUTOMATIC and STATIC decls.
> >         * parse.c (decode_specification_statement, decode_statement): Ditto.
> >         * resolve.c (apply_default_init_local, resolve_fl_variable_derived,
> >         resolve_symbol): Support for automatic attribute.
> >         * symbol.c (check_conflict, gfc_copy_attr, gfc_is_var_automatic):
> >         Ditto.
> >         * trans-decl.c (gfc_finish_var_decl): Ditto.
> >
> >     gcc/testsuite/gfortran.dg/
> >         * dec_static_1.f90, dec_static_2.f90: New testcases.
>


---
Fritz Reese

Re: Ping**2! Re: [PATCH, Fortran] Extension: AUTOMATIC/STATIC symbol attributes with -fdec-static

[Andre Vehreschild]

Hi Fritz,

please note: I do not have official review privileges. So my vote here
is rather an advise to you and the official reviewers. Often such a
inofficial review helps to speed things up, because the official ones
are pointed to the nics and nacs and don't have to bother with the
minor things.

So here it comes:

- Do I understand this correctly: AUTOMATIC and STATIC have to come last,
  i.e., right before the :: where declaring, e.g., a variable?


- Running:

  $ contrib/check_GNU_style.sh dec_static.patch

  Reports some style issues in the C code, that should be fixed before
  commit. (Style in Fortran testcases does not matter that much.)


- I have deleted huge parts of the diff and just kept the parts I had a
  question/remark for:

> diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
> index b34ae86..a0cf78b 100644
> --- a/gcc/fortran/gfortran.texi
> +++ b/gcc/fortran/gfortran.texi
> @@ -2120,7 +2121,6 @@ consider @code{BACKSPACE} or @code{REWIND} to properly position
>  the file before the EOF marker.  As an extension, the run-time error may
>  be disabled using -std=legacy.
>  
> -

Please change formatting in a separate patch or not at all (here!).
This policy is to distinguish cosmetic changes from relevant ones.

>  @node STRUCTURE and RECORD
>  @subsection @code{STRUCTURE} and @code{RECORD}
>  @cindex @code{STRUCTURE}
> @@ -2420,6 +2420,53 @@ here:
>    @tab @code{--} @tab @code{FLOATI} @tab @code{FLOATJ} @tab @code{FLOATK}
>  @end multitable
>  
> +@node AUTOMATIC and STATIC attributes
> +@subsection @code{AUTOMATIC} and @code{STATIC} attributes
> +@cindex variable attributes
> +@cindex @code{AUTOMATIC}
> +@cindex @code{STATIC}
> +
> +With @option{-fdec-static} GNU Fortran supports the explicit specification of
> +two addition variable attributes: @code{STATIC} and @code{AUTOMATIC}. These

two additional variable ...
            ^^ 

But is it only for variables? Can't it be used for equivalences or
other constructs, too?

> diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
> index 15c131a..a5da59e 100644
> --- a/gcc/fortran/invoke.texi
> +++ b/gcc/fortran/invoke.texi
> @@ -255,6 +255,11 @@ instead where possible.
>  Enable B/I/J/K kind variants of existing integer functions (e.g. BIAND, IIAND,
>  JIAND, etc...). For a complete list of intrinsics see the full documentation.
>  
> +@item -fdec-static
> +@opindex @code{fdec-static}
> +Enable STATIC and AUTOMATIC as attributes specifying storage location.
> +STATIC is equivalent to SAVE, and locals are typically AUTOMATIC by default.

Well, this description to me sounds like: "Those attributes are
useless, because they can be substituted." This is clearly not what you
intend. I propose to include into the description that with "this
switch the dec-extension" is available "to explicitly specify the
storage of entities". Then the last sentence is still a good hint for
all fortraneers that don't know the extension.

> +
>  @item -fdollar-ok
>  @opindex @code{fdollar-ok}
>  @cindex @code{$}
> diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
> index 8ec5400..260512d 100644
> --- a/gcc/fortran/lang.opt
> +++ b/gcc/fortran/lang.opt
> @@ -432,6 +432,10 @@ fdec-structure
>  Fortran
>  Enable support for DEC STRUCTURE/RECORD.
>  
> +fdec-static
> +Fortran Var(flag_dec_static)
> +Enable STATIC and AUTOMATIC attributes.

How about: Enable the dec-extension of STATIC and AUTOMATIC attributes.
Just a proposal.

> +
>  fdefault-double-8
>  Fortran Var(flag_default_double)
>  Set the default double precision kind to an 8 byte wide type.


> diff --git a/gcc/testsuite/gfortran.dg/dec_static_1.f90 b/gcc/testsuite/gfortran.dg/dec_static_1.f90
> new file mode 100644
> index 0000000..4dcfc7c
> --- /dev/null
> +++ b/gcc/testsuite/gfortran.dg/dec_static_1.f90

-  Please add some testcases where the new error messages are tested.

So much from my side. Btw, I haven't applied the patch and tested
whether it runs or collides with other proposed patches. That is
usually done by Dominique and I did not want to waste doing it a second
time.

Regards,
	Andre
-- 
Andre Vehreschild * Email: vehre ad gmx dot de 

Re: Ping**2! Re: [PATCH, Fortran] Extension: AUTOMATIC/STATIC symbol attributes with -fdec-static

[Fritz Reese]

[-- Attachment #1: Type: text/plain, Size: 6250 bytes --]

On Wed, Sep 7, 2016 at 9:31 AM, Andre Vehreschild <vehre@gmx.de> wrote:
> Hi Fritz,
>
> please note: I do not have official review privileges. So my vote here
> is rather an advise to you and the official reviewers. Often such a
> inofficial review helps to speed things up, because the official ones
> are pointed to the nics and nacs and don't have to bother with the
> minor things.

Andre,

Thank you very much for your comments. I have only been contributing
to GNU/GCC for a year or two and appreciate the advice. I definitely
strive to keep my patches in line with the relevant standards and
style guides. Attached is a replacement for the original patch which
addresses your concerns.


> - Do I understand this correctly: AUTOMATIC and STATIC have to come last,
>   i.e., right before the :: where declaring, e.g., a variable?
Not quite, you are probably misled by this code in decl.c:

> match
> gfc_match_static (void)
> {
...
> gfc_match (" ::");

(And equivalent for gfc_match_automatic.) These are similar to
gfc_match_save, and like gfc_match_save are only called to match
variable attribute specification _statements_, such as:
> SAVE :: x
> AUTOMATIC :: y

STATIC and AUTOMATIC are matched in any order in an attribute
specification _list_, as with SAVE, through the giant switch() earlier
in decl.c/match_attr_spec(). This applies to the following:
> INTEGER, SAVE, DIMENSION(3) :: x
> INTEGER, AUTOMATIC, DIMENSION(3) :: y


> - Running:
>
>   $ contrib/check_GNU_style.sh dec_static.patch
>
>   Reports some style issues in the C code, that should be fixed before
>   commit. (Style in Fortran testcases does not matter that much.)
I was not aware of this script - thanks!


> Please change formatting in a separate patch or not at all (here!).
> This policy is to distinguish cosmetic changes from relevant ones.
Fixed. These changes are usually accidental - I try not to reformat
code that I'm not otherwise touching.


>> diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
...
>> +With @option{-fdec-static} GNU Fortran supports the explicit specification of
>> +two addition variable attributes: @code{STATIC} and @code{AUTOMATIC}. These
...
> But is it only for variables? Can't it be used for equivalences or
> other constructs, too?
Yes, good point, perhaps 'entities' is a better term here:

+With @option{-fdec-static} GNU Fortran supports the DEC extended attributes
+@code{STATIC} and @code{AUTOMATIC} to provide explicit specification of entity
+storage. [...]

>> diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
...
>> +@item -fdec-static
>> +@opindex @code{fdec-static}
>> +Enable STATIC and AUTOMATIC as attributes specifying storage location.
>> +STATIC is equivalent to SAVE, and locals are typically AUTOMATIC by default.
>
> Well, this description to me sounds like: "Those attributes are
> useless, because they can be substituted." This is clearly not what you
> intend. I propose to include into the description that with "this
> switch the dec-extension" is available "to explicitly specify the
> storage of entities". Then the last sentence is still a good hint for
> all fortraneers that don't know the extension.

I guess I subconsciously made them sound "useless" because I hoped
users would think twice about using the extensions and use standard
conforming constructs instead. :-)  But, maybe you are right and this
would be clearer:

+@item -fdec-static
+@opindex @code{fdec-static}
+Enable DEC-style STATIC and AUTOMATIC attributes to explicitly specify
+the storage of variables and other objects.


>> diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
...
>> +fdec-static
>> +Fortran Var(flag_dec_static)
>> +Enable STATIC and AUTOMATIC attributes.
>
> How about: Enable the dec-extension of STATIC and AUTOMATIC attributes.
> Just a proposal.
How about this, to match invoke.texi:

+fdec-static
+Fortran Var(flag_dec_static)
+Enable DEC-style STATIC and AUTOMATIC attributes.


> -  Please add some testcases where the new error messages are tested.
Yes, good idea! cf. attached for dec_static_3.f90 and
dec_static_4.f90. These tests gave me a chance to realize I should
emit some better error messages so I made a minor change there:

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index db431dd..be8e9f7 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -7838,6 +7838,8 @@ gfc_match_automatic (void)
       switch (m)
       {
       case MATCH_NO:
+        break;
+
       case MATCH_ERROR:
         return MATCH_ERROR;

@@ -7856,7 +7858,7 @@ gfc_match_automatic (void)

   if (!seen_symbol)
     {
-      gfc_error ("Expected var-list in AUTOMATIC statement at %C");
+      gfc_error ("Expected entity-list in AUTOMATIC statement at %C");
       return MATCH_ERROR;
     }

... And similar for gfc_match_static. (Nb. "entity-list" was chosen to
correspond with the "save-entity-list" descriptor used by F90 to
specify the SAVE statement.)

Andre, thanks again for your comments. I hope the attached patch is
acceptable for trunk; now pending official review once again.

---
Fritz Reese

2016-09-07  Fritz Reese  <fritzoreese@gmail.com>

    Support for AUTOMATIC and STATIC attributes with new flag -fdec-static.

    gcc/fortran/
        * lang.opt, invoke.texi, gfortran.texi: New flag -fdec-static.
        * options.c (set_dec_flags): Set -fdec-static with -fdec.
        * gfortran.h (symbol_attribute): New attribute automatic.
        * gfortran.h (gfc_add_automatic): New prototype.
        * match.h (gfc_match_automatic, gfc_match_static): New functions.
        * decl.c (gfc_match_automatic, gfc_match_static): Ditto.
        * symbol.c (gfc_add_automatic): Ditto.
        * decl.c (match_attr_spec): Match AUTOMATIC and STATIC decls.
        * parse.c (decode_specification_statement, decode_statement): Ditto.
        * resolve.c (apply_default_init_local, resolve_fl_variable_derived,
        resolve_symbol): Support for automatic attribute.
        * symbol.c (check_conflict, gfc_copy_attr, gfc_is_var_automatic):
        Ditto.
        * trans-decl.c (gfc_finish_var_decl): Ditto.

    gcc/testsuite/gfortran.dg/
        * dec_static_1.f90, dec_static_2.f90, dec_static_3.f90,
        dec_static_4.f90: New testcases.

[-- Attachment #2: dec_static2.patch --]
[-- Type: text/x-patch, Size: 24244 bytes --]

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index ce5ebb7..be8e9f7 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -3794,6 +3794,7 @@ match_attr_spec (void)
     DECL_ALLOCATABLE = GFC_DECL_BEGIN, DECL_DIMENSION, DECL_EXTERNAL,
     DECL_IN, DECL_OUT, DECL_INOUT, DECL_INTRINSIC, DECL_OPTIONAL,
     DECL_PARAMETER, DECL_POINTER, DECL_PROTECTED, DECL_PRIVATE,
+    DECL_STATIC, DECL_AUTOMATIC,
     DECL_PUBLIC, DECL_SAVE, DECL_TARGET, DECL_VALUE, DECL_VOLATILE,
     DECL_IS_BIND_C, DECL_CODIMENSION, DECL_ASYNCHRONOUS, DECL_CONTIGUOUS,
     DECL_NONE, GFC_DECL_END /* Sentinel */
@@ -3857,6 +3858,14 @@ match_attr_spec (void)
 		      d = DECL_ASYNCHRONOUS;
 		    }
 		  break;
+
+		case 'u':
+		  if (match_string_p ("tomatic"))
+		    {
+		      /* Matched "automatic".  */
+		      d = DECL_AUTOMATIC;
+		    }
+		  break;
 		}
 	      break;
 
@@ -3986,8 +3995,25 @@ match_attr_spec (void)
 	      break;
 
 	    case 's':
-	      if (match_string_p ("save"))
-		d = DECL_SAVE;
+	      gfc_next_ascii_char ();
+	      switch (gfc_next_ascii_char ())
+		{
+		  case 'a':
+		    if (match_string_p ("ve"))
+		      {
+			/* Matched "save".  */
+			d = DECL_SAVE;
+		      }
+		    break;
+
+		  case 't':
+		    if (match_string_p ("atic"))
+		      {
+			/* Matched "static".  */
+			d = DECL_STATIC;
+		      }
+		    break;
+		}
 	      break;
 
 	    case 't':
@@ -4124,6 +4150,12 @@ match_attr_spec (void)
 	  case DECL_SAVE:
 	    attr = "SAVE";
 	    break;
+	  case DECL_STATIC:
+	    attr = "STATIC";
+	    break;
+	  case DECL_AUTOMATIC:
+	    attr = "AUTOMATIC";
+	    break;
 	  case DECL_TARGET:
 	    attr = "TARGET";
 	    break;
@@ -4152,6 +4184,18 @@ match_attr_spec (void)
       if (seen[d] == 0)
 	continue;
 
+      if ((d == DECL_STATIC || d == DECL_AUTOMATIC)
+	  && !flag_dec_static)
+	{
+	  gfc_error ("%s at %L is a DEC extension, enable with -fdec-static",
+		     d == DECL_STATIC ? "STATIC" : "AUTOMATIC", &seen_at[d]);
+	  m = MATCH_ERROR;
+	  goto cleanup;
+	}
+      /* Allow SAVE with STATIC, but don't complain.  */
+      if (d == DECL_STATIC && seen[DECL_SAVE])
+	continue;
+
       if (gfc_current_state () == COMP_DERIVED
 	  && d != DECL_DIMENSION && d != DECL_CODIMENSION
 	  && d != DECL_POINTER   && d != DECL_PRIVATE
@@ -4290,10 +4334,15 @@ match_attr_spec (void)
 			      &seen_at[d]);
 	  break;
 
+	case DECL_STATIC:
 	case DECL_SAVE:
 	  t = gfc_add_save (&current_attr, SAVE_EXPLICIT, NULL, &seen_at[d]);
 	  break;
 
+	case DECL_AUTOMATIC:
+	  t = gfc_add_automatic (&current_attr, NULL, &seen_at[d]);
+	  break;
+
 	case DECL_TARGET:
 	  t = gfc_add_target (&current_attr, &seen_at[d]);
 	  break;
@@ -7767,6 +7816,114 @@ gfc_match_parameter (void)
 }
 
 
+match
+gfc_match_automatic (void)
+{
+  gfc_symbol *sym;
+  match m;
+  bool seen_symbol = false;
+
+  if (!flag_dec_static)
+    {
+      gfc_error ("AUTOMATIC at %C is a DEC extension, enable with "
+		 "-fdec-static");
+      return MATCH_ERROR;
+    }
+
+  gfc_match (" ::");
+
+  for (;;)
+    {
+      m = gfc_match_symbol (&sym, 0);
+      switch (m)
+      {
+      case MATCH_NO:
+        break;
+
+      case MATCH_ERROR:
+	return MATCH_ERROR;
+
+      case MATCH_YES:
+	if (!gfc_add_automatic (&sym->attr, sym->name, &gfc_current_locus))
+	  return MATCH_ERROR;
+	seen_symbol = true;
+	break;
+      }
+
+      if (gfc_match_eos () == MATCH_YES)
+	break;
+      if (gfc_match_char (',') != MATCH_YES)
+	goto syntax;
+    }
+
+  if (!seen_symbol)
+    {
+      gfc_error ("Expected entity-list in AUTOMATIC statement at %C");
+      return MATCH_ERROR;
+    }
+
+  return MATCH_YES;
+
+syntax:
+  gfc_error ("Syntax error in AUTOMATIC statement at %C");
+  return MATCH_ERROR;
+}
+
+
+match
+gfc_match_static (void)
+{
+  gfc_symbol *sym;
+  match m;
+  bool seen_symbol = false;
+
+  if (!flag_dec_static)
+    {
+      gfc_error ("STATIC at %C is a DEC extension, enable with -fdec-static");
+      return MATCH_ERROR;
+    }
+
+  gfc_match (" ::");
+
+  for (;;)
+    {
+      m = gfc_match_symbol (&sym, 0);
+      switch (m)
+      {
+      case MATCH_NO:
+        break;
+
+      case MATCH_ERROR:
+	return MATCH_ERROR;
+
+      case MATCH_YES:
+	if (!gfc_add_save (&sym->attr, SAVE_EXPLICIT, sym->name,
+			  &gfc_current_locus))
+	  return MATCH_ERROR;
+	seen_symbol = true;
+	break;
+      }
+
+      if (gfc_match_eos () == MATCH_YES)
+	break;
+      if (gfc_match_char (',') != MATCH_YES)
+	goto syntax;
+    }
+
+  if (!seen_symbol)
+    {
+      gfc_error ("Expected entity-list in STATIC statement at %C");
+      return MATCH_ERROR;
+    }
+
+  return MATCH_YES;
+
+syntax:
+  gfc_error ("Syntax error in STATIC statement at %C");
+  return MATCH_ERROR;
+}
+
+
 /* Save statements have a special syntax.  */
 
 match
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 813f7d9..2e30994 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -726,7 +726,7 @@ typedef struct
     optional:1, pointer:1, target:1, value:1, volatile_:1, temporary:1,
     dummy:1, result:1, assign:1, threadprivate:1, not_always_present:1,
     implied_index:1, subref_array_pointer:1, proc_pointer:1, asynchronous:1,
-    contiguous:1, fe_temp: 1;
+    contiguous:1, fe_temp: 1, automatic: 1;
 
   /* For CLASS containers, the pointer attribute is sometimes set internally
      even though it was not directly specified.  In this case, keep the
@@ -2803,6 +2803,7 @@ bool gfc_add_cray_pointee (symbol_attribute *, locus *);
 match gfc_mod_pointee_as (gfc_array_spec *);
 bool gfc_add_protected (symbol_attribute *, const char *, locus *);
 bool gfc_add_result (symbol_attribute *, const char *, locus *);
+bool gfc_add_automatic (symbol_attribute *, const char *, locus *);
 bool gfc_add_save (symbol_attribute *, save_state, const char *, locus *);
 bool gfc_add_threadprivate (symbol_attribute *, const char *, locus *);
 bool gfc_add_omp_declare_target (symbol_attribute *, const char *, locus *);
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index b34ae86..44b6041 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -1462,6 +1462,7 @@ without warning.
 * STRUCTURE and RECORD::
 * UNION and MAP::
 * Type variants for integer intrinsics::
+* AUTOMATIC and STATIC attributes::
 @end menu
 
 @node Old-style kind specifications
@@ -2420,6 +2421,56 @@ here:
   @tab @code{--} @tab @code{FLOATI} @tab @code{FLOATJ} @tab @code{FLOATK}
 @end multitable
 
+@node AUTOMATIC and STATIC attributes
+@subsection @code{AUTOMATIC} and @code{STATIC} attributes
+@cindex variable attributes
+@cindex @code{AUTOMATIC}
+@cindex @code{STATIC}
+
+With @option{-fdec-static} GNU Fortran supports the DEC extended attributes
+@code{STATIC} and @code{AUTOMATIC} to provide explicit specification of entity
+storage.  These follow the syntax of the Fortran standard @code{SAVE} attribute.
+
+@code{STATIC} is exactly equivalent to @code{SAVE}, and specifies that
+an entity should be allocated in static memory.  As an example, @code{STATIC}
+local variables will retain their values across multiple calls to a function.
+
+Entities marked @code{AUTOMATIC} will be stack automatic whenever possible.
+@code{AUTOMATIC} is the default for local variables smaller than
+@option{-fmax-stack-var-size}, unless @option{-fno-automatic} is given.  This
+attribute overrides @option{-fno-automatic}, @option{-fmax-stack-var-size}, and
+blanket @code{SAVE} statements.
+
+
+Examples:
+
+@example
+subroutine f
+  integer, automatic :: i  ! automatic variable
+  integer x, y             ! static variables
+  save
+  ...
+endsubroutine
+@end example
+@example
+subroutine f
+  integer a, b, c, x, y, z
+  static :: x
+  save y
+  automatic z, c
+  ! a, b, c, and z are automatic
+  ! x and y are static
+endsubroutine
+@end example
+@example
+! Compiled with -fno-automatic
+subroutine f
+  integer a, b, c, d
+  automatic :: a
+  ! a is automatic; b, c, and d are static
+endsubroutine
+@end example
+
 
 @node Extensions not implemented in GNU Fortran
 @section Extensions not implemented in GNU Fortran
@@ -2443,7 +2494,6 @@ code that uses them running with the GNU Fortran compiler.
 * ENCODE and DECODE statements::
 * Variable FORMAT expressions::
 @c * Q edit descriptor::
-@c * AUTOMATIC statement::
 @c * TYPE and ACCEPT I/O Statements::
 @c * .XOR. operator::
 @c * CARRIAGECONTROL, DEFAULTFILE, DISPOSE and RECORDTYPE I/O specifiers::
diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index 15c131a..268d155 100644
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -116,7 +116,7 @@ by type.  Explanations are in the following sections.
 @xref{Fortran Dialect Options,,Options controlling Fortran dialect}.
 @gccoptlist{-fall-intrinsics -fbackslash -fcray-pointer -fd-lines-as-code @gol
 -fd-lines-as-comments @gol
--fdec -fdec-structure -fdec-intrinsic-ints @gol
+-fdec -fdec-structure -fdec-intrinsic-ints -fdec-static @gol
 -fdefault-double-8 -fdefault-integer-8 @gol
 -fdefault-real-8 -fdollar-ok -ffixed-line-length-@var{n} @gol
 -ffixed-line-length-none -ffree-form -ffree-line-length-@var{n} @gol
@@ -241,7 +241,7 @@ full documentation.
 
 Other flags enabled by this switch are:
 @option{-fdollar-ok} @option{-fcray-pointer} @option{-fdec-structure}
-@option{-fdec-intrinsic-ints}
+@option{-fdec-intrinsic-ints} @option{-fdec-static}
 
 @item -fdec-structure
 @opindex @code{fdec-structure}
@@ -255,6 +255,11 @@ instead where possible.
 Enable B/I/J/K kind variants of existing integer functions (e.g. BIAND, IIAND,
 JIAND, etc...). For a complete list of intrinsics see the full documentation.
 
+@item -fdec-static
+@opindex @code{fdec-static}
+Enable DEC-style STATIC and AUTOMATIC attributes to explicitly specify
+the storage of variables and other objects.
+
 @item -fdollar-ok
 @opindex @code{fdollar-ok}
 @cindex @code{$}
diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
index 8ec5400..ef421d3 100644
--- a/gcc/fortran/lang.opt
+++ b/gcc/fortran/lang.opt
@@ -432,6 +432,10 @@ fdec-structure
 Fortran
 Enable support for DEC STRUCTURE/RECORD.
 
+fdec-static
+Fortran Var(flag_dec_static)
+Enable DEC-style STATIC and AUTOMATIC attributes.
+
 fdefault-double-8
 Fortran Var(flag_default_double)
 Set the default double precision kind to an 8 byte wide type.
diff --git a/gcc/fortran/match.h b/gcc/fortran/match.h
index 348ca70..2413163 100644
--- a/gcc/fortran/match.h
+++ b/gcc/fortran/match.h
@@ -223,6 +223,7 @@ void gfc_set_constant_character_len (int, gfc_expr *, int);
 /* Matchers for attribute declarations.  */
 match gfc_match_allocatable (void);
 match gfc_match_asynchronous (void);
+match gfc_match_automatic (void);
 match gfc_match_codimension (void);
 match gfc_match_contiguous (void);
 match gfc_match_dimension (void);
@@ -238,6 +239,7 @@ match gfc_match_protected (void);
 match gfc_match_private (gfc_statement *);
 match gfc_match_public (gfc_statement *);
 match gfc_match_save (void);
+match gfc_match_static (void);
 match gfc_match_modproc (void);
 match gfc_match_target (void);
 match gfc_match_value (void);
diff --git a/gcc/fortran/options.c b/gcc/fortran/options.c
index 4aa8303..13dfa88 100644
--- a/gcc/fortran/options.c
+++ b/gcc/fortran/options.c
@@ -54,6 +54,7 @@ set_dec_flags (int value)
 {
     gfc_option.flag_dec_structure  = value;
     flag_dec_intrinsic_ints = value;
+    flag_dec_static = value;
 }
 
 
diff --git a/gcc/fortran/parse.c b/gcc/fortran/parse.c
index bd7b138..4d684f6 100644
--- a/gcc/fortran/parse.c
+++ b/gcc/fortran/parse.c
@@ -191,6 +191,7 @@ decode_specification_statement (void)
 	     ST_INTERFACE);
       match ("allocatable", gfc_match_allocatable, ST_ATTR_DECL);
       match ("asynchronous", gfc_match_asynchronous, ST_ATTR_DECL);
+      match ("automatic", gfc_match_automatic, ST_ATTR_DECL);
       break;
 
     case 'b':
@@ -256,6 +257,7 @@ decode_specification_statement (void)
 
     case 's':
       match ("save", gfc_match_save, ST_ATTR_DECL);
+      match ("static", gfc_match_static, ST_ATTR_DECL);
       match ("structure", gfc_match_structure_decl, ST_STRUCTURE_DECL);
       break;
 
@@ -436,6 +438,7 @@ decode_statement (void)
       match ("allocatable", gfc_match_allocatable, ST_ATTR_DECL);
       match ("assign", gfc_match_assign, ST_LABEL_ASSIGNMENT);
       match ("asynchronous", gfc_match_asynchronous, ST_ATTR_DECL);
+      match ("automatic", gfc_match_automatic, ST_ATTR_DECL);
       break;
 
     case 'b':
@@ -548,6 +551,7 @@ decode_statement (void)
       match ("sequence", gfc_match_eos, ST_SEQUENCE);
       match ("stop", gfc_match_stop, ST_STOP);
       match ("save", gfc_match_save, ST_ATTR_DECL);
+      match ("static", gfc_match_static, ST_ATTR_DECL);
       match ("submodule", gfc_match_submodule, ST_SUBMODULE);
       match ("sync all", gfc_match_sync_all, ST_SYNC_ALL);
       match ("sync images", gfc_match_sync_images, ST_SYNC_IMAGES);
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 7763f9c..d822f05 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -11237,10 +11237,11 @@ apply_default_init_local (gfc_symbol *sym)
      entry, so we just add a static initializer. Note that automatic variables
      are stack allocated even with -fno-automatic; we have also to exclude
      result variable, which are also nonstatic.  */
-  if (sym->attr.save || sym->ns->save_all
-      || (flag_max_stack_var_size == 0 && !sym->attr.result
-	  && (sym->ns->proc_name && !sym->ns->proc_name->attr.recursive)
-	  && (!sym->attr.dimension || !is_non_constant_shape_array (sym))))
+  if (!sym->attr.automatic
+      && (sym->attr.save || sym->ns->save_all
+	  || (flag_max_stack_var_size == 0 && !sym->attr.result
+	      && (sym->ns->proc_name && !sym->ns->proc_name->attr.recursive)
+	      && (!sym->attr.dimension || !is_non_constant_shape_array (sym)))))
     {
       /* Don't clobber an existing initializer!  */
       gcc_assert (sym->value == NULL);
@@ -11385,7 +11386,7 @@ resolve_fl_variable_derived (gfc_symbol *sym, int no_init_flag)
      a hidden default for allocatable components.  */
   if (!(sym->value || no_init_flag) && sym->ns->proc_name
       && sym->ns->proc_name->attr.flavor == FL_MODULE
-      && !sym->ns->save_all && !sym->attr.save
+      && !(sym->ns->save_all && !sym->attr.automatic) && !sym->attr.save
       && !sym->attr.pointer && !sym->attr.allocatable
       && gfc_has_default_initializer (sym->ts.u.derived)
       && !gfc_notify_std (GFC_STD_F2008, "Implied SAVE for module variable "
@@ -14159,7 +14160,7 @@ resolve_symbol (gfc_symbol *sym)
   if (class_attr.codimension
       && !(class_attr.allocatable || sym->attr.dummy || sym->attr.save
 	   || sym->attr.select_type_temporary
-	   || sym->ns->save_all
+	   || (sym->ns->save_all && !sym->attr.automatic)
 	   || sym->ns->proc_name->attr.flavor == FL_MODULE
 	   || sym->ns->proc_name->attr.is_main_program
 	   || sym->attr.function || sym->attr.result || sym->attr.use_assoc))
@@ -14311,7 +14312,8 @@ resolve_symbol (gfc_symbol *sym)
     }
 
   /* Check threadprivate restrictions.  */
-  if (sym->attr.threadprivate && !sym->attr.save && !sym->ns->save_all
+  if (sym->attr.threadprivate && !sym->attr.save
+      && !(sym->ns->save_all && !sym->attr.automatic)
       && (!sym->attr.in_common
 	  && sym->module == NULL
 	  && (sym->ns->proc_name == NULL
@@ -14322,7 +14324,7 @@ resolve_symbol (gfc_symbol *sym)
   if (sym->attr.omp_declare_target
       && sym->attr.flavor == FL_VARIABLE
       && !sym->attr.save
-      && !sym->ns->save_all
+      && !(sym->ns->save_all && !sym->attr.automatic)
       && (!sym->attr.in_common
 	  && sym->module == NULL
 	  && (sym->ns->proc_name == NULL
diff --git a/gcc/fortran/symbol.c b/gcc/fortran/symbol.c
index c967f25..0ae957e 100644
--- a/gcc/fortran/symbol.c
+++ b/gcc/fortran/symbol.c
@@ -373,7 +373,7 @@ check_conflict (symbol_attribute *attr, const char *name, locus *where)
     *is_bind_c = "BIND(C)", *procedure = "PROCEDURE",
     *proc_pointer = "PROCEDURE POINTER", *abstract = "ABSTRACT",
     *asynchronous = "ASYNCHRONOUS", *codimension = "CODIMENSION",
-    *contiguous = "CONTIGUOUS", *generic = "GENERIC";
+    *contiguous = "CONTIGUOUS", *generic = "GENERIC", *automatic = "AUTOMATIC";
   static const char *threadprivate = "THREADPRIVATE";
   static const char *omp_declare_target = "OMP DECLARE TARGET";
   static const char *oacc_declare_copyin = "OACC DECLARE COPYIN";
@@ -438,6 +438,7 @@ check_conflict (symbol_attribute *attr, const char *name, locus *where)
       conf (dummy, save);
       conf (in_common, save);
       conf (result, save);
+      conf (automatic, save);
 
       switch (attr->flavor)
 	{
@@ -479,6 +480,12 @@ check_conflict (symbol_attribute *attr, const char *name, locus *where)
   conf (pointer, codimension);
   conf (allocatable, elemental);
 
+  conf (in_common, automatic);
+  conf (in_equivalence, automatic);
+  conf (result, automatic);
+  conf (use_assoc, automatic);
+  conf (dummy, automatic);
+
   conf (target, external);
   conf (target, intrinsic);
 
@@ -933,6 +940,21 @@ gfc_add_allocatable (symbol_attribute *attr, locus *where)
 
 
 bool
+gfc_add_automatic (symbol_attribute *attr, const char *name, locus *where)
+{
+  if (check_used (attr, name, where))
+    return false;
+
+  if (attr->automatic && !gfc_notify_std (GFC_STD_LEGACY,
+	"Duplicate AUTOMATIC attribute specified at %L", where))
+    return false;
+
+  attr->automatic = 1;
+  return check_conflict (attr, name, where);
+}
+
+
+bool
 gfc_add_codimension (symbol_attribute *attr, const char *name, locus *where)
 {
 
@@ -1880,6 +1902,8 @@ gfc_copy_attr (symbol_attribute *dest, symbol_attribute *src, locus *where)
   if (src->allocatable && !gfc_add_allocatable (dest, where))
     goto fail;
 
+  if (src->automatic && !gfc_add_automatic (dest, NULL, where))
+    goto fail;
   if (src->dimension && !gfc_add_dimension (dest, NULL, where))
     goto fail;
   if (src->codimension && !gfc_add_codimension (dest, NULL, where))
@@ -3991,6 +4015,10 @@ gfc_is_var_automatic (gfc_symbol *sym)
       && sym->ts.u.cl
       && !gfc_is_constant_expr (sym->ts.u.cl->length))
     return true;
+  /* Variables with explicit AUTOMATIC attribute.  */
+  if (sym->attr.automatic)
+      return true;
+
   return false;
 }
 
diff --git a/gcc/fortran/trans-decl.c b/gcc/fortran/trans-decl.c
index 6cf7f57..05fa877 100644
--- a/gcc/fortran/trans-decl.c
+++ b/gcc/fortran/trans-decl.c
@@ -647,7 +647,7 @@ gfc_finish_var_decl (tree decl, gfc_symbol * sym)
     }
 
   /* Keep variables larger than max-stack-var-size off stack.  */
-  if (!sym->ns->proc_name->attr.recursive
+  if (!sym->ns->proc_name->attr.recursive && !sym->attr.automatic
       && INTEGER_CST_P (DECL_SIZE_UNIT (decl))
       && !gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl))
 	 /* Put variable length auto array pointers always into stack.  */
diff --git a/gcc/testsuite/gfortran.dg/dec_static_1.f90 b/gcc/testsuite/gfortran.dg/dec_static_1.f90
new file mode 100644
index 0000000..7f319ec
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dec_static_1.f90
@@ -0,0 +1,42 @@
+! { dg-do run }
+! { dg-options "-fdec-static -finit-local-zero" }
+!
+! Test AUTOMATIC and STATIC attributes.
+!
+subroutine assert(s, i1, i2)
+  implicit none
+  integer, intent(in)      :: i1, i2
+  character(*), intent(in) :: s
+  if (i1 .ne. i2) then
+    print *, s, ": expected ", i2, " but was ", i1
+    call abort
+  endif
+endsubroutine assert
+
+function f (x, y)
+  implicit none
+  integer f
+  integer, intent(in)  :: x, y
+  integer              :: a    ! only a can actually be saved
+  integer, automatic   :: c    ! should actually be automatic
+  save
+
+  ! a should be incremented by x every time and saved
+  a = a + x
+  f = a
+
+  ! c should be zeroed every time, therefore equal y
+  c = c + y
+  call assert ("f%c", c, y)
+  return
+endfunction
+
+implicit none
+integer :: f
+
+! Should return static value of a; accumulates x
+call assert ("f()", f(1,3), 1)
+call assert ("f()", f(1,4), 2)
+call assert ("f()", f(1,2), 3)
+
+end
diff --git a/gcc/testsuite/gfortran.dg/dec_static_2.f90 b/gcc/testsuite/gfortran.dg/dec_static_2.f90
new file mode 100644
index 0000000..392f342
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dec_static_2.f90
@@ -0,0 +1,58 @@
+! { dg-do run }
+! { dg-options "-fdec-static -fno-automatic -finit-local-zero" }
+!
+! Test STATIC and AUTOMATIC with -fno-automatic and recursive subroutines.
+!
+subroutine assert(s, i1, i2)
+  implicit none
+  integer, intent(in)      :: i1, i2
+  character(*), intent(in) :: s
+  if (i1 .ne. i2) then
+    print *, s, ": expected ", i2, " but was ", i1
+    call abort
+  endif
+endsubroutine
+
+function f (x)
+implicit none
+  integer f
+  integer, intent(in) :: x
+  integer, static     :: a ! should be SAVEd
+  a = a + x ! should increment by x every time
+  f = a
+  return
+endfunction
+
+recursive subroutine g (x)
+implicit none
+  integer, intent(in) :: x
+  integer, automatic  :: a ! should be automatic (in recursive)
+  a = a + x ! should be set to x every time
+  call assert ("g%a", a, x)
+endsubroutine
+
+subroutine h (x)
+implicit none
+  integer, intent(in) :: x
+  integer, automatic  :: a ! should be automatic (outside recursive)
+  a = a + x ! should be set to x every time
+  call assert ("h%a", a, x)
+endsubroutine
+
+implicit none
+integer :: f
+
+! Should return static value of c; accumulates x
+call assert ("f()", f(3), 3)
+call assert ("f()", f(4), 7)
+call assert ("f()", f(2), 9)
+
+call g(3)
+call g(4)
+call g(2)
+
+call h(3)
+call h(4)
+call h(2)
+
+end
diff --git a/gcc/testsuite/gfortran.dg/dec_static_3.f90 b/gcc/testsuite/gfortran.dg/dec_static_3.f90
new file mode 100644
index 0000000..48b6220
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dec_static_3.f90
@@ -0,0 +1,20 @@
+! { dg-do compile }
+! { dg-options "" }
+!
+! Check errors for use of STATIC/AUTOMATIC without -fdec-static.
+!
+
+subroutine s()
+  implicit none
+  integer, automatic :: a ! { dg-error "is a DEC extension" }
+  integer, static :: b ! { dg-error "is a DEC extension" }
+  integer, save :: c
+
+  integer :: auto1, auto2, static1, static2, save1, save2
+  automatic auto1 ! { dg-error "is a DEC extension" }
+  automatic :: auto2 ! { dg-error "is a DEC extension" }
+  static static1 ! { dg-error "is a DEC extension" }
+  static :: static2 ! { dg-error "is a DEC extension" }
+  save save1
+  save :: save2
+end subroutine
diff --git a/gcc/testsuite/gfortran.dg/dec_static_4.f90 b/gcc/testsuite/gfortran.dg/dec_static_4.f90
new file mode 100644
index 0000000..91bed19
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dec_static_4.f90
@@ -0,0 +1,38 @@
+! { dg-do compile }
+! { dg-options "-fdec-static" }
+!
+! Check for conflicts between STATIC/AUTOMATIC and other attributes.
+!
+
+function s(a, b, x, y) result(z)
+  implicit none
+  integer, automatic, intent(IN) :: a ! { dg-error "DUMMY attribute conflicts" }
+  integer, static, intent(IN) :: b ! { dg-error "DUMMY attribute conflicts" }
+  integer, intent(OUT) :: x, y
+  automatic :: x ! { dg-error "DUMMY attribute conflicts" }
+  static :: y ! { dg-error "DUMMY attribute conflicts" }
+
+  automatic ! { dg-error "Expected entity-list in AUTOMATIC statement" }
+  automatic :: ! { dg-error "Expected entity-list in AUTOMATIC statement" }
+  static ! { dg-error "Expected entity-list in STATIC statement" }
+  static :: ! { dg-error "Expected entity-list in STATIC statement" }
+
+  integer, automatic :: auto1, auto2
+  integer, static :: static1, static2
+  integer :: auto3, static3
+  automatic :: auto3
+  static :: static3
+
+  common /c1/ auto1, auto2 ! { dg-error "COMMON attribute conflicts" }
+  common /c2/ static1, static2 ! { dg-error "COMMON attribute conflicts" }
+  common /c3/ auto3, static3 ! { dg-error "COMMON attribute conflicts" }
+
+  integer, static :: z ! { dg-error "RESULT attribute conflicts" }
+  integer, automatic :: z ! { dg-error "RESULT attribute conflicts" }
+  static :: z ! { dg-error "RESULT attribute conflicts" }
+  automatic :: z ! { dg-error "RESULT attribute conflicts" }
+
+  integer, static, automatic :: o ! { dg-error "AUTOMATIC attribute conflicts" }
+
+  integer :: a, b, z ! fall-back decls so we don't get "no implicit type"
+end