Re: [PATCH] Set default to -fomit-frame-pointer

[Sandra Loosemore <sandra at codesourcery dot com>]

On 11/03/2017 10:54 AM, Wilco Dijkstra wrote:
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 71b2445f70fd5b832c68c08e69e71d8ecad37a4a..1c56f4b12495fe97c604200ef245c9fa02684b0f 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -7436,16 +7436,17 @@ machine-description macro @code{FRAME_POINTER_REQUIRED} controls
>   whether a target machine supports this flag.  @xref{Registers,,Register
>   Usage, gccint, GNU Compiler Collection (GCC) Internals}.
>
> -The default setting (when not optimizing for
> -size) for 32-bit GNU/Linux x86 and 32-bit Darwin x86 targets is
> -@option{-fomit-frame-pointer}.  You can configure GCC with the
> -@option{--enable-frame-pointer} configure option to change the default.
> +The default setting is @option{-fomit-frame-pointer}.  You can configure GCC
> +with the @option{--enable-frame-pointer} configure option to change the default.

I'd prefer that you remove the reference to configure options entirely 
here.  Nowadays most GCC users install a package provided by their OS 
distribution, Linaro, etc, rather than trying to build GCC from scratch.

>   Note that @option{-fno-omit-frame-pointer} doesn't force a new stack
>   frame for all functions if it isn't otherwise needed, and hence doesn't
> -guarantee a new frame pointer for all functions.
> +guarantee a new frame pointer for all functions.  Several targets always omit
> +the frame pointer in leaf functions.
> +
> +Enabled at levels @option{-O}, @option{-O1}, @option{-O2}, @option{-O3},
> +@option{-Os} and @option{-Og}.

This last sentence makes no sense.  If the option is now enabled by 
default, then the optimization level is irrelevant.

-Sandra