[rfc] nopl should not be output on -mtune=i686

Jan Kratochvil jan.kratochvil@redhat.com
Tue Feb 8 19:01:00 GMT 2011


On Tue, 08 Feb 2011 18:23:35 +0100, H.J. Lu wrote:
> On Tue, Feb 8, 2011 at 9:10 AM, Jan Kratochvil
> <jan.kratochvil@redhat.com> wrote:
> > Current binutils HEAD:
> > -march | -mtune  | nopl used?  | after the attached patch: nopl used?
> >  -    |   -     |    no       | no
> >  i686  | -/i686  |    no       | no
> >  -    |   i686  |   yes = BUG | no
> >  core2 | -/core2 |   yes       | yes
> >  -    |   core2 |   yes = BUG | no
> >
> > => Currently suppressing -march now produces more advanced code output, this
> >   does not seem correct to me.
> 
> By default, x86 assembler assumes that the target processor accepts
> any instructions.  You can restrict ISA sets by -march and .arch directive.

Aha, in such case the system build should use some specific -march anyway and
not just to disable `nopl'.

Andreas Schwab has reopened now this one, it should be NOTABUG:
http://sourceware.org/bugzilla/show_bug.cgi?id=6957


> > The flag `+nop' (such as `-march=i686+nop') does not work for me as expected
> > with HEAD and neither works with the patched code.
> 
> Please file a bug report.

I see your fix, thanks.


Thanks,
Jan



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