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.
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
> >>
