On Fri, Apr 25, 2025 at 3:06 PM Andi Kleen <a...@firstfloor.org> wrote:
>
> 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.
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
> >> >>
