Re: [PATCH 2/2] Fortran: Add attribute flatten

[Mikael Morin <morin-mikael@orange.fr>]

Le 10/11/2022 à 11:20, Bernhard Reutner-Fischer via Fortran a écrit :
> Bootstrapped and regtested cleanly on x86_unknown-linux.
> The document bits will be rewritten for rst.
> Ok for trunk if the prerequisite target_clones patch is approved?
> 
> gcc/fortran/ChangeLog:
> 
> 	* decl.cc (gfc_match_gcc_attributes): Handle flatten.
> 	* f95-lang.cc (gfc_attribute_table): Add flatten.
> 	* gfortran.texi: Document attribute flatten.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gfortran.dg/attr_flatten-1.f90: New test.
> ---
>   gcc/fortran/decl.cc                          |  8 +++-
>   gcc/fortran/f95-lang.cc                      |  2 +
>   gcc/fortran/gfortran.texi                    |  8 ++++
>   gcc/testsuite/gfortran.dg/attr_flatten-1.f90 | 41 ++++++++++++++++++++
>   4 files changed, 57 insertions(+), 2 deletions(-)
>   create mode 100644 gcc/testsuite/gfortran.dg/attr_flatten-1.f90
> 
> diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
> index d312d4812b6..3d210c26eb5 100644
> --- a/gcc/fortran/decl.cc
> +++ b/gcc/fortran/decl.cc
(...)
> @@ -11849,7 +11850,9 @@ gfc_match_gcc_attributes (void)
>   	if (strcmp (name, ext_attr_list[id].name) == 0)
>   	  break;
>   
> -      if (id == EXT_ATTR_LAST)
> +      if (strcmp (name, "flatten") == 0)
> +	known_attr0args = true; /* Handled below.  We do not need a bit.  */

I don't see the point to have all the attributes needing a bit except 
one that doesn't but needs a specific handling.
What does it look like without the 1/2 patch and if one bit is also used 
for flatten, like the other attributes?

> +      else if (id == EXT_ATTR_LAST)
>   	{
>   	  gfc_error ("Unknown attribute in !GCC$ ATTRIBUTES statement at %C");
>   	  return MATCH_ERROR;

> diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
> index 06e4c8c00a1..be650f28b62 100644
> --- a/gcc/fortran/gfortran.texi
> +++ b/gcc/fortran/gfortran.texi
> @@ -3280,6 +3280,14 @@ contains
>   end module mymod
>   @end smallexample
>   
> +@node flatten
> +
> +Procedures annotated with the @code{flatten} attribute have their
> +callees inlined, if possible.
I'm not a native speaker, but I find this sentence confusing.
The words of the gcc manual you are refering to seem more clear: "every 
call inside the function is inlined, if possible".

> +Please refer to
> +@ref{Top,,Common Function Attributes,gcc,Using the GNU Compiler Collection (GCC)}
> +for details about the respective attribute.
> +
>   The attributes are specified using the syntax
>   
>   @code{!GCC$ ATTRIBUTES} @var{attribute-list} @code{::} @var{variable-list}