[PATCH] c/67925 - update documentation on `inline'

[Martin Sebor]

On 10/13/2015 04:47 PM, Arkadiusz Drabczyk wrote:
> * gcc/doc/extend.texi: documentation says that functions declared
> `inline' would not be integrated if they are called before they are
> defined or if they are recursive. Both of these statements is now
> false as shown in examples on Bugzilla.

It might also be worth updating the note in the subsequent
paragraph and removing the mention of variable-length data types
which no longer prevent inlining.

FWIW, the list of most -Winline warnings issued by GCC is here
(there are two more in Ada which, AFAICT, have to do with nested
functions):

$ grep -A1 "can never be inlined" gcc/tree-inline.c
	    = G_("function %q+F can never be inlined because it uses "
		 "alloca (override using the always_inline attribute)");
--
	    = G_("function %q+F can never be inlined because it uses setjmp");
	  *handled_ops_p = true;
--
	      = G_("function %q+F can never be inlined because it "
		   "uses variable argument lists");
--
	      = G_("function %q+F can never be inlined because "
		   "it uses setjmp-longjmp exception handling");
--
	      = G_("function %q+F can never be inlined because "
		   "it uses non-local goto");
--
	      = G_("function %q+F can never be inlined because "
		   "it uses __builtin_return or __builtin_apply_args");
--
	    = G_("function %q+F can never be inlined "
		 "because it contains a computed goto");
--
         warning (OPT_Winline, "function %q+F can never be inlined 
because it "
                  "is suppressed using -fno-inline", fn);
--
         warning (OPT_Winline, "function %q+F can never be inlined 
because it "
                  "uses attributes conflicting with inlining", fn);

Martin

> ---
>   gcc/doc/extend.texi | 9 +++------
>   1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index 79440d3..7ea4b62 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -7088,12 +7088,9 @@ function are integrated into the caller, and the function's address is
>   never used, then the function's own assembler code is never referenced.
>   In this case, GCC does not actually output assembler code for the
>   function, unless you specify the option @option{-fkeep-inline-functions}.
> -Some calls cannot be integrated for various reasons (in particular,
> -calls that precede the function's definition cannot be integrated, and
> -neither can recursive calls within the definition).  If there is a
> -nonintegrated call, then the function is compiled to assembler code as
> -usual.  The function must also be compiled as usual if the program
> -refers to its address, because that can't be inlined.
> +If there is a nonintegrated call, then the function is compiled to
> +assembler code as usual.  The function must also be compiled as usual if
> +the program refers to its address, because that can't be inlined.
>
>   @opindex Winline
>   Note that certain usages in a function definition can make it unsuitable
>