On 2025-04-23 10:18, Richard Biener wrote:
On Tue, Apr 22, 2025 at 5:43 PM Andi Kleen <a...@firstfloor.org> wrote:
On 2025-04-22 13:22, Richard Biener wrote:
> On Sat, Apr 12, 2025 at 5:09 PM Andi Kleen <a...@firstfloor.org> wrote:
>>
>> From: Andi Kleen <a...@gcc.gnu.org>
>>
>> ... that uses -march=native -mtune=native to build a compiler
>> optimized
>> for the host.
>
> -march=native implies -mtune=native so I think the latter is redundant.
Ok with that change?
Put the list back in the loop.
>
>> config/ChangeLog:
>>
>> * bootstrap-native.mk: New file.
>>
>> gcc/ChangeLog:
>>
>> * doc/install.texi: Document bootstrap-native.
>> ---
>> config/bootstrap-native.mk | 1 +
>> gcc/doc/install.texi | 7 +++++++
>> 2 files changed, 8 insertions(+)
>> create mode 100644 config/bootstrap-native.mk
>>
>> diff --git a/config/bootstrap-native.mk b/config/bootstrap-native.mk
>> new file mode 100644
>> index 00000000000..a4a3d859408
>> --- /dev/null
>> +++ b/config/bootstrap-native.mk
>> @@ -0,0 +1 @@
>> +BOOT_CFLAGS := -march=native -mtune=native $(BOOT_CFLAGS)
>
> bootstrap-O3 uses
>
> BOOT_CFLAGS := -O3 $(filter-out -O%, $(BOOT_CFLAGS))
>
> so do you want to filer-out other -march/-mtune/-mcpu options?
I don't think that is needed because these are usually not used
(unlike
-O)
>
> Some targets know -mcpu= instead of -march=, did you check whether
> any of those have =native?
There are some like Alpha and others dont jave it at all. That is the
why the documentation says "if supported".
I see.
So yes, OK with the above change.
Based on Tamars comment the original patch seems better because it works
correctly on aarch which should have much more users than the exotic
architectures. Also many of then are likely cross compiler only. So I
would like to commit the original patch if its ok.
Thanks,
Andi
Richard.
>
>> diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
>> index 4973f195daf..04a2256b97a 100644
>> --- a/gcc/doc/install.texi
>> +++ b/gcc/doc/install.texi
>> @@ -3052,6 +3052,13 @@ Removes any @option{-O}-started option from
>> @code{BOOT_CFLAGS}, and adds
>> @itemx @samp{bootstrap-Og}
>> Analogous to @code{bootstrap-O1}.
>>
>> +@item @samp{bootstrap-native}
>> +@itemx @samp{bootstrap-native}
>> +Optimize the compiler code for the build host, if supported by the
>> +architecture. Note this only affects the compiler, not the targeted
>> +code. If you want the later, choose options suitable to the target
>> you
>> +are looking for. For example @samp{--with-cpu} would be a good
>> starting point.
>> +
>> @item @samp{bootstrap-lto}
>> Enables Link-Time Optimization for host tools during bootstrapping.
>> @samp{BUILD_CONFIG=bootstrap-lto} is equivalent to adding
>> --
>> 2.47.1
>>
