On 4/8/19 2:42 PM, Richard Biener wrote:
> On Mon, Apr 8, 2019 at 2:26 PM Martin Liška <mli...@suse.cz> wrote:
>>
>> On 4/8/19 2:18 PM, Richard Biener wrote:
>>> On Mon, Apr 8, 2019 at 1:30 PM Martin Liška <mli...@suse.cz> wrote:
>>>>
>>>> On 4/8/19 12:08 PM, Richard Biener wrote:
>>>>> On Fri, Apr 5, 2019 at 12:42 PM Martin Liška <mli...@suse.cz> wrote:
>>>>>>
>>>>>> Hi.
>>>>>>
>>>>>> The patch adds a new config that makes LTO+PGO bootstrap faster by
>>>>>> using LTO only in stage4. In stage3, generators are build with LTO
>>>>>> in order to collect a reasonable profile for LTO FE.
>>>>>>
>>>>>> Ready for trunk?
>>>>>
>>>>> I wonder if you need the
>>>>>
>>>>> +AC_SUBST(GENERATOR_CFLAGS)
>>>>>
>>>>> at all, can't you just use
>>>>>
>>>>> +BUILD_CFLAGS= @BUILD_CFLAGS@ $(GENERATOR_CFLAGS) -DGENERATOR_FILE
>>>>> +BUILD_CXXFLAGS = @BUILD_CXXFLAGS@ $(GENERATOR_CFLAGS) -DGENERATOR_FILE
>>>>>
>>>>> ?
>>>>
>>>> I've just tested that and it does not work for me.
>>>
>>> Ah, you probably need to move the
>>>
>>> @@ -1124,6 +1125,7 @@ configure-stage[+id+]-[+prefix+][+module+]:
>>> CXXFLAGS="$(CXXFLAGS_FOR_TARGET)"; export CXXFLAGS; \
>>> LIBCFLAGS="$(LIBCFLAGS_FOR_TARGET)"; export LIBCFLAGS;[+ ELSE
>>> prefix +] \
>>> CFLAGS="$(STAGE[+id+]_CFLAGS)"; export CFLAGS; \
>>> + GENERATOR_CFLAGS="$(STAGE[+id+]_GENERATOR_CFLAGS)"; export
>>> GENERATOR_CFLAGS; \
>>> CXXFLAGS="$(STAGE[+id+]_CXXFLAGS)"; export CXXFLAGS;[+ IF prev +] \
>>>
>>> change to the respective build targets.
>>
>> Can you please point me to a location in Makefile.tpl where
>> is the target? It's all Greek to me :)
>
> I think it's
>
> all-stage[+id+]-[+prefix+][+module+]:
> configure-stage[+id+]-[+prefix+][+module+]
> @[ $(current_stage) = stage[+id+] ] || $(MAKE) stage[+id+]-start
> @r=`${PWD_COMMAND}`; export r; \
> s=`cd $(srcdir); ${PWD_COMMAND}`; export s; \
> TFLAGS="$(STAGE[+id+]_TFLAGS)"; \
> [+exports+][+ IF prev +] \
> [+poststage1_exports+][+ ENDIF prev +] [+extra_exports+] \
> cd [+subdir+]/[+module+] && \
> [+autoprofile+] \
> $(MAKE) $(BASE_FLAGS_TO_PASS)[+ IF prefix +] \
> CFLAGS="$(CFLAGS_FOR_TARGET)" \
> CXXFLAGS="$(CXXFLAGS_FOR_TARGET)" \
> LIBCFLAGS="$(LIBCFLAGS_FOR_TARGET)"[+ ELSE prefix +] \
> CFLAGS="$(STAGE[+id+]_CFLAGS)" \
> CXXFLAGS="$(STAGE[+id+]_CXXFLAGS)"[+ IF prev +] \
> LIBCFLAGS="$(STAGE[+id+]_CFLAGS)"[+ ELSE prev +] \
> LIBCFLAGS="$(LIBCFLAGS)"[+ ENDIF prev +][+ ENDIF prefix +] \
> CFLAGS_FOR_TARGET="$(CFLAGS_FOR_TARGET)" \
> CXXFLAGS_FOR_TARGET="$(CXXFLAGS_FOR_TARGET)" \
> LIBCFLAGS_FOR_TARGET="$(LIBCFLAGS_FOR_TARGET)" \
> [+args+] [+IF prev +][+poststage1_args+][+ ELSE prev +] \
> [+stage1_args+][+ ENDIF prev +] [+extra_make_flags+] \
> TFLAGS="$(STAGE[+id+]_TFLAGS)" [+profile_data+] \
> $(TARGET-stage[+id+]-[+prefix+][+module+])
>
> where you maybe can simply add a
> GENERATOR_CFLAGS="$(STAGE[+id+]_GENERATOR_CFLAGS)
>
> Richard.
>
>> Martin
>>
>>>
>>>>>
>>>>> Please mention in both bootstrap-lto-lean.mk and the documentation
>>>>> that the intended make target for this config is profiledbootstrap
>>>>> since for non-profiledbootstrap it ends up not using LTO at all. A "lean"
>>>>> mode for non-profiledbootstrap would need to set up things to
>>>>> use LTO only for stage3 which means not doing a bootstrap comparison
>>>>> which means we could "skip" stage2 as well here. So partial support
>>>>> for that would be to have
>>>>>
>>>>> STAGE2_CFLAGS += -frandom-seed=1
>>>>> STAGE3_CFLAGS += -flto=jobserver -frandom-seed=1
>>>>> ...
>>>>> do-compare = true
>>>>
>>>> Changed to tihs.
>>>>
>>>>>
>>>>> So if this works for non-profiledbootstrap the docs could be
>>>>> changed to say "but is intended for faster build by only
>>>>> using LTO in the final bootstrap stage. With @samp{...}
>>>>> the LTO frontend is trained only on generator files."
>>>>
>>>> Likewise.
>>>>
>>>>>
>>>>> (why do we need -frandom-seed=1? IIRC that was only for the
>>>>> comparison step which is elided in all cases for -lean.mk).
>>>>
>>>> Yep, it's not neded now.
>>>
>>> I see it still on STAGE[23]_CFLAGS? I think you can drop
>>> STAGE2_CFLAGS adjustment completely.
>>>
>>> Otherwise looks OK - mind trying one more time with the
>>> above suggestion for GENERATOR_CFLAGS?
>>>
>>> Thanks,
>>> Richard.
>>>
>>>> Martin
>>>>
>>>>>
>>>>> Richard.
>>>>>
>>>>>> Thanks,
>>>>>> Martin
>>>>>>
>>>>>> ChangeLog:
>>>>>>
>>>>>> 2019-04-05 Martin Liska <mli...@suse.cz>
>>>>>>
>>>>>> * Makefile.in: Regenerate.
>>>>>> * Makefile.tpl: Pass GENERATOR_CFLAGS
>>>>>> in all stages.
>>>>>>
>>>>>> config/ChangeLog:
>>>>>>
>>>>>> 2019-04-05 Martin Liska <mli...@suse.cz>
>>>>>>
>>>>>> * bootstrap-lto-lean.mk: New file.
>>>>>>
>>>>>> gcc/ChangeLog:
>>>>>>
>>>>>> 2019-04-05 Martin Liska <mli...@suse.cz>
>>>>>>
>>>>>> * Makefile.in: Use GENERATOR_CFLAGS for all generators.
>>>>>> * configure: Regenerate.
>>>>>> * configure.ac: Pass GENERATOR_CFLAGS.
>>>>>> * doc/install.texi: Document the new config.
>>>>>> ---
>>>>>> Makefile.in | 207 +++++++++++++++++++++++++++++++++++
>>>>>> Makefile.tpl | 2 +
>>>>>> config/bootstrap-lto-lean.mk | 19 ++++
>>>>>> gcc/Makefile.in | 4 +-
>>>>>> gcc/configure | 6 +-
>>>>>> gcc/configure.ac | 1 +
>>>>>> gcc/doc/install.texi | 6 +
>>>>>> 7 files changed, 241 insertions(+), 4 deletions(-)
>>>>>> create mode 100644 config/bootstrap-lto-lean.mk
>>>>>>
>>>>>>
>>>>
>>
Works for me. There's the update patch that also removes the usage
of 'frandom-seed=1'.
Ready for trunk?
Thanks,
Martin
