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Re: [PATCH, libcpp]: Use x86 __builtin_ia32_pcmpestri128 instead of asm.
On Tue, Jun 19, 2012 at 8:38 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Tue, Jun 19, 2012 at 12:07 AM, Richard Henderson <rth@redhat.com> wrote:
>> On 2012-06-18 13:19, Uros Bizjak wrote:
>>> ? ? ? ?/* ??? The builtin doesn't understand that the PCMPESTRI read from
>>> ? ? ? ?memory need not be aligned. ?*/
>>> - ? ? ?__asm ("%vpcmpestri $0, (%1), %2"
>>> - ? ? ? ? ?: "=c"(index) : "r"(s), "x"(search), "a"(4), "d"(16));
>>> + ? ? ?sv = __builtin_ia32_loaddqu ((const char *) s);
>>> + ? ? ?index = __builtin_ia32_pcmpestri128 (search, 4, sv, 16, 0);
>>> +
>>
>>
>> Surely the comment can be removed too then?
>
> I'm not sure there. The builtin, as defined, expects V16QI operand
> with xm constraint. Using:
>
> int test (const char *s1)
> {
> ?const v16qi *p = (const v16qi *)(unsigned long) s1;
> ?return __builtin_ia32_pcmpistri128 (*p, ...);
> }
>
> will generate movdqa before pcmpistri.
Pedantic correction: __builtin_ia32_pcmpistri128 (v16qi_arg, *p, N);
movdqa in front of this builtin will be generated with -O0.
Uros.