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Re: [PATCH 2/5] x86: improve SIMD to‑scalar‑int conversion insn handling
>>> On 22.03.18 at 13:18, <hjl.tools@gmail.com> wrote:
> On Thu, Mar 22, 2018 at 5:06 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>> On 22.03.18 at 12:54, <hjl.tools@gmail.com> wrote:
>>> On Thu, Mar 22, 2018 at 4:42 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>>> On 22.03.18 at 12:23, <hjl.tools@gmail.com> wrote:
>>>>> On Thu, Mar 22, 2018 at 12:42 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>>>>> On 21.03.18 at 20:17, <hjl.tools@gmail.com> wrote:
>>>>>>> On Wed, Mar 21, 2018 at 7:20 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>>>>>> In the course of folding their patterns (possible now that the pointless
>>>>>>>> and partly even bogus VecESize are no longer in the way) I've noticed
>>>>>>>> that vcvt*2usi, other than their vcvt*2si counterparts, didn't allow for
>>>>>>>> any suffixes. As with all insns touching GPRs, these should be permitted
>>>>>>>> even if they're not required for determining operand sizes. In turn I've
>>>>>>>> noticed that only a very limited set of cases had a suffix added in
>>>>>>>> disassembly with -Msuffix, while all suffixes should be output in that
>>>>>>>> mode.
>>>>>>>>
>>>>>>>> gas/
>>>>>>>> 2018-03-21 Jan Beulich <jbeulich@suse.com>
>>>>>>>>
>>>>>>>> * testsuite/gas/i386/cvt-2si.d, testsuite/gas/i386/cvt-2si.s:
>>>>>>>> New.
>>>>>>>> * testsuite/gas/i386/i386.exp: Run new test.
>>>>>>>> * testsuite/gas/i386/ilp32/x86-64-simd-suffix.d,
>>>>>>>> testsuite/gas/i386/simd-suffix.d,
>>>>>>>> testsuite/gas/i386/x86-64-simd-suffix.d: Adjust expectations.
>>>>>>>>
>>>>>>>> opcodes/
>>>>>>>> 2018-03-21 Jan Beulich <jbeulich@suse.com>
>>>>>>>>
>>>>>>>> * i386-dis.c (prefix_table): Replace Y by S for cvt*2si.
>>>>>>>> (vex_len_table): Replace Y by S for vcvt*2si.
>>>>>>>> (putop): Replace plain 'Y' handling by abort().
>>>>>>>> * i386-dis-evex.h (evex_table): Replace Y by S for vcvt*2si.
>>>>>>>> * i386-opc.tbl (vcvt*d2si): Fold AVX512 forms. Add ToDword.
>>>>>>>> (vcvt*s2si): Fold AVX512 forms. Add ToQword.
>>>>>>>> * i386-tlb.h: Re-generate.
>>>>>>>
>>>>>>> I prefer not to add suffixes to vector instructions with GPRs unless it
>>>>>>> is required.
>>>>>>
>>>>>> I'm afraid I don't follow - suffixes (in particular in suffix-always
>>>>>> mode) aren't an optional thing. I actually consider it a mistake
>>>>>> for the compiler to omit them, and the compiler _has to_ omit
>>>>>> them right now because we don't accept them. Furthermore -
>>>>>> did you look at the state things are currently in? If you didn't
>>>>>> want suffixes when not needed, why is there the Y format in
>>>>>> the first place? And why said inconsistency between 2usi and
>>>>>> 2si conversions in the assembler? And more fundamentally -
>>>>>> why are vector insns different from others touching GPRs?
>[...]
> If we exclude integer instructions from this discussion, vector
> instructions are quite consistent without suffix. Yes, some vector
> instructions do need suffixes, but only a few.
Some _need_ suffixes, yes. Various other _allow_ for suffixes.
Once again, would you mind actually reading what I've said in the
patch description as well as answering the questions I've raised?
_I did point out_ the inconsistencies I'm seeing, yet you continue
to talk in general terms.
Jan