[PATCH] x86: imply all No_*Suf when none is set in a template

[Jan Beulich]

On 15.11.2019 19:05,  H.J. Lu  wrote:
> On Fri, Nov 15, 2019 at 12:35 AM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> On 14.11.2019 20:26, H.J. Lu wrote:
>>> On Thu, Nov 14, 2019 at 12:51 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>>
>>>> Since no template would ever allow for none of them to be set, reduce
>>>> table size and improve readability and hence maintainability by implying
>>>> all of them to be set when a template specifies none.
>>>>
>>>> opcodes/
>>>> 2019-11-XX  Jan Beulich  <jbeulich@suse.com>
>>>>
>>>>         * i386-gen.c (process_i386_opcode_modifier): Widen scope of
>>>>         bwlq_suf. New local variable other_suf. Emit warning when all
>>>>         No_*Suf are set. Set all No_*Suf when none are set.
>>>>         * i386-opc.tbl: Drop No_bSuf, No_wSuf, No_lSuf, No_sSuf,
>>>>         No_qSuf, and No_ldSuf when they're all specified at the same
>>>>         time.
>>>
>>> I don't think it may the table more readable.   Why not simply add
>>>
>>> #define  No_Suf  No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf
>>>
>>> and use it?
>>
>> Because this would require yet another global change once we switch
>> to positive identification of the permitted suffixes (which should
>> have been done from the beginning imo). Since the set of suffixes
>> that can go together is pretty limited (i.e. a fair subset of the
>> combinations currently possible to specify do never occur), my plan
>> is to switch to an enumeration here, containing enumerators like
>> bwlqSuf or wlqSuf.
> 
> Replace or remove No_Suf should be very easy.

"easy" is not a category of my thinking here. It's the huge amount
of code churn and the resulting unless-ness of e.g. "git blame" that
I'd like to avoid. Dropping the code again that this patch adds to
i386-gen.c is also "easy" enough.

Jan