Re: [PATCH v8 2/2] x86/AT&T: don't default to byte source for ambiguous for MOVSX/MOVZX

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Feb 14, 2020 at 6:23 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 14.02.2020 15:16, H.J. Lu wrote:
> > On Fri, Feb 14, 2020 at 5:54 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>
> >> On 14.02.2020 13:28, H.J. Lu wrote:
> >>> On Fri, Feb 14, 2020 at 4:26 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>>>
> >>>> As pointed out in "x86: replace adhoc (partly wrong) ambiguous operand
> >>>> checking for MOVSX/MOVZX" silently guessing what the programmer may have
> >>>> meant is not helpful, the more that we don't do so elsewhere anymore
> >>>> (except in cases where it is overwhelmingly likely that the other case
> >>>> isn't meant, like here for it meant to be a "sign/zero extension" from
> >>>> 16 bits to 16 bits).
> >>>>
> >>>> gas/
> >>>> 2020-02-XX  Jan Beulich  <jbeulich@suse.com>
> >>>>
> >>>>         PR gas/25438
> >>>>         * config/tc-i386.c (process_suffix): Default movsx/movzx to byte
> >>>>         suffix only when destination is a word reg.
> >>>>         testsuite/gas/i386/noreg16.l, testsuite/gas/i386/noreg32.l,
> >>>>         testsuite/gas/i386/noreg64.l: Adjust expectations.
> >>>
> >>> No need for this since this is documented behavior of AT&T syntax.
> >>
> >> I've just looked at the documentation again: As said in the
> >> other reply to your doc change, these mnemonics aren't
> >> mentioned as legal in Solaris'es AT&T spec. And I also
> >> can't find gas doc saying so. Would you please point me at
> >> where this is being documented?
> >
> > Solaris spec doesn't mention movsx[bwl] nor movsx.
>
> Right, so where did you take from that "this is documented behavior"?
>

Documented in gas manual.

-- 
H.J.