Re: [PATCH, committed] Change default for powerpc -msave-toc-indirect

[Richard Guenther <richard dot guenther at gmail dot com>]

On Mon, Aug 29, 2011 at 11:32 PM, Michael Meissner
<meissner@linux.vnet.ibm.com> wrote:
> David asked me to reverse the default for the -msave-toc-indirect option, since
> it is buggy in a few cases, and in other places causes slowdowns if the
> function has an early exit before calling the indrect function. ?I also
> documented the switch.
>
> I did the usual bootstrap and make check with no regressions, and committed the
> patch.

Was this switch available in 4.6.x?  If so please document the change of the
default in gcc-4.7/changes.html.

Thanks,
Richard.

> 2011-08-29 ?Michael Meissner ?<meissner@linux.vnet.ibm.com>
>
> ? ? ? ?* config/rs6000/rs6000.opt (-msave-toc-indirect): Change default
> ? ? ? ?to off. ?Document switch.
> ? ? ? ?* doc/invoke.texi (-msave-toc-indirect): Ditto.
>
> Index: gcc/config/rs6000/rs6000.opt
> ===================================================================
> --- gcc/config/rs6000/rs6000.opt ? ? ? ?(revision 178259)
> +++ gcc/config/rs6000/rs6000.opt ? ? ? ?(working copy)
> @@ -526,5 +526,5 @@ Target Report Var(TARGET_POINTERS_TO_NES
> ?Use/do not use r11 to hold the static link in calls to functions via pointers.
>
> ?msave-toc-indirect
> -Target Undocumented Var(TARGET_SAVE_TOC_INDIRECT) Save Init(1)
> -; Control whether we save the TOC in the prologue for indirect calls or generate the save inline
> +Target Report Var(TARGET_SAVE_TOC_INDIRECT) Save
> +Control whether we save the TOC in the prologue for indirect calls or generate the save inline
> Index: gcc/doc/invoke.texi
> ===================================================================
> --- gcc/doc/invoke.texi (revision 178259)
> +++ gcc/doc/invoke.texi (working copy)
> @@ -814,7 +814,8 @@ See RS/6000 and PowerPC Options.
> ?-mrecip -mrecip=@var{opt} -mno-recip -mrecip-precision @gol
> ?-mno-recip-precision @gol
> ?-mveclibabi=@var{type} -mfriz -mno-friz @gol
> --mpointers-to-nested-functions -mno-pointers-to-nested-functions}
> +-mpointers-to-nested-functions -mno-pointers-to-nested-functions @gol
> +-msave-toc-indirect -mno-save-toc-indirect}
>
> ?@emph{RX Options}
> ?@gccoptlist{-m64bit-doubles ?-m32bit-doubles ?-fpu ?-nofpu@gol
> @@ -16438,6 +16439,15 @@ static chain value to be loaded in regis
> ?not be able to call through pointers to nested functions or pointers
> ?to functions compiled in other languages that use the static chain if
> ?you use the @option{-mno-pointers-to-nested-functions}.
> +
> +@item -msave-toc-indirect
> +@itemx -mno-save-toc-indirect
> +@opindex msave-toc-indirect
> +Generate (do not generate) code to save the TOC value in the reserved
> +stack location in the function prologue if the function calls through
> +a pointer on AIX and 64-bit Linux systems. ?If the TOC value is not
> +saved in the prologue, it is saved just before the call through the
> +pointer. ?The @option{-mno-save-toc-indirect} option is the default.
> ?@end table
>
> ?@node RX Options
>
>
> --
> Michael Meissner, IBM
> 5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
> meissner@linux.vnet.ibm.com ? ? fax +1 (978) 399-6899
>