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DateSat, 29 Dec 2007 11:52:53 +0200
FromAdrian Bunk <>
SubjectRe: [PATCH] x86: unify x86 Makefile(s)
On Sat, Dec 29, 2007 at 10:39:04AM +0100, Sam Ravnborg wrote:
> On Sat, Dec 29, 2007 at 12:13:24AM +0200, Adrian Bunk wrote:
> > On Fri, Dec 28, 2007 at 10:23:41PM +0100, Sam Ravnborg wrote:
> > >...> > > Noteworthy remarks on the unification:> > >...> > > - -funit-at-a-time should be easy to unify but it looks like we have a bug
> > >   in 32 bit. We only enable -funit-at-a-time for gcc less than 0400 if they
> > >   support it> > > > No, we _dis_able it on 32bit if a gcc < 4.0 supports it.> I have:> $ gcc --version> gcc (GCC) 4.1.2 20070925 (Red Hat 4.1.2-33)> > And with the current code in arch/x86/Makefile_32 I do not
> have -funit-at-a-time.>...

You do not have this option, but you do not need it since it's enabled 
with -O in all gcc versions that support it except for some vendor 
backports to gcc 3.3.

>...> This is the relevant snippet from the Makefile:> KBUILD_CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then echo $(call cc-option,-fno-unit-at-a-time); fi ;)
> > It reads:> If gcc version is less than 4.00 then enable -funit-at-a-time only for gcc that supports it.
> -funit-at-a-time is NOT enabled for gcc >= 4.00

It is not _explicitely_ enabled for gcc >= 4.0 since it's anyway enabled.

> So it will enable -funit-at-a-time for gcc 3.4 as it is now.
> Which was what we wanted to avoid..> So I see no reason not to enable it uncondintionally (if gcc supports it) as we have
> used it for 3.4 for as long as we have introduced -funit-at-a-time.

We have never used it with gcc 3.4 on i386.

> 	Sam

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed



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