Re: [PATCH] Define HAS_CPUID/HAS_I586/HAS_I686 from -march=

[Mike Frysinger <vapier at gentoo dot org>]

On 18 Aug 2015 09:08, H.J. Lu wrote:
> On Tue, Aug 18, 2015 at 9:02 AM, Mike Frysinger wrote:
> > On 18 Aug 2015 07:56, H.J. Lu wrote:
> >> On Tue, Aug 18, 2015 at 7:32 AM, Mike Frysinger wrote:
> >> > On 17 Aug 2015 16:10, H.J. Lu wrote:
> >> >> +#ifdef __x86_64__
> >> >> +# define HAS_CPUID 1
> >> >> +#elif defined __pentium__
> >> >> +# define HAS_CPUID 1
> >> >> +# define HAS_I586 1
> >> >> +# define HAS_I686 0
> >> >> +#elif (defined __pentiumpro__ || defined __pentium4__                \
> >> >> +       || defined __nocona__ || defined __atom__             \
> >> >> +       || defined __core2__ || defined __corei7__            \
> >> >> +       || defined __corei7_avx__ || defined __core_avx2__    \
> >> >> +       || defined __nehalem__ || defined __sandybridge__     \
> >> >> +       || defined __haswell__  || defined __knl__            \
> >> >> +       || defined __bonnell__ || defined __silvermont__      \
> >> >> +       || defined __k6__ || defined __k8__                   \
> >> >> +       || defined __athlon__ || defined __amdfam10__         \
> >> >> +       || defined __bdver1__ || defined __bdver2__           \
> >> >> +       || defined __bdver3__ || defined __bdver4__           \
> >> >> +       || defined __btver1__ || defined __btver2__)
> >> >> +# define HAS_CPUID 1
> >> >> +# define HAS_I586 1
> >> >> +# define HAS_I686 1
> >> >> +#else
> >> >> +# define HAS_CPUID 0
> >> >> +# define HAS_I586 0
> >> >> +# define HAS_I686 0
> >> >> +#endif
> >> >
> >> > why is testing for __i686__ & __i586__ unacceptable ?
> >>
> >> -march=haswell doesn't define __i686__ since __i686__ is
> >> mapped to -mach=i686.
> >
> > that's not entirely accurate.  i did check before posting, but it looks like
> > the first two entries do set up i586 and i686 correctly (and i stopped after
> > spot checking the first two).  so i guess change __pentium__ to __i586__ and
> > __pentiumpro__ to __i686__ ?
> 
> My change is based on sysdeps/x86/bits/string.h and
> sysdeps/x86/bits/byteswap.h.  None of them check
> __i586__ nor __i686__.

i'm aware of the provenance.  that's not a reason to not improve things :).
-mike

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