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

[H.J. Lu]

On Fri, Feb 14, 2020 at 7:52 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 14.02.2020 15:37, H.J. Lu wrote:
> > On Fri, Feb 14, 2020 at 6:32 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>
> >> On 14.02.2020 15:25, H.J. Lu wrote:
> >>> 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.
> >>
> >> Where? As said, I did look there without finding anything to this effect.
> >
> > It is there now.
>
> Hmm, even worse: It's not there. Neither of the two doc changes of
> yours today say anything like this. Did you forget to both post a
> patch _and_ push it, or am I blind, or are you simply lying to me?
> I'm sorry for being blunt, but I'm getting really annoyed.
>

info as.info on master branch shows


 The Intel-syntax extension instructions

   * 'movsx' -- sign-extend 'reg8/mem8' to 'reg16'.

   * 'movsx' -- sign-extend 'reg8/mem8' to 'reg32'.

   * 'movsx' -- sign-extend 'reg8/mem8' to 'reg64' (x86-64 only).

   * 'movsx' -- sign-extend 'reg16/mem16' to 'reg32'

   * 'movsx' -- sign-extend 'reg16/mem16' to 'reg64' (x86-64 only).

   * 'movsxd' -- sign-extend 'reg32/mem32' to 'reg64' (x86-64 only).

   * 'movzx' -- zero-extend 'reg8/mem8' to 'reg16'.

   * 'movzx' -- zero-extend 'reg8/mem8' to 'reg32'.

   * 'movzx' -- zero-extend 'reg8/mem8' to 'reg64' (x86-64 only).

   * 'movzx' -- zero-extend 'reg16/mem16' to 'reg32'

   * 'movzx' -- zero-extend 'reg16/mem16' to 'reg64' (x86-64 only).

are called 'movsbw/movsxb/movsx', 'movsbl/movsxb/movsx',
'movsbq/movsb/movsx', 'movswl/movsxw', 'movswq/movsxw', 'movslq/movsxl',
'movzbw/movzxb/movzx', 'movzbl/movzxb/movzx', 'movzbq/movzxb/movzx',
'movzwl/movzxw' and 'movzwq/movzxw' in AT&T syntax.


-- 
H.J.