On Mon, Mar 17, 2014 at 10:11 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Mon, Mar 17, 2014 at 9:52 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>> On Mon, Mar 17, 2014 at 4:12 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>
>>>> Patch in the bottom allows to use ymmXX and zmmXX
>>>> register names in inline asm statements as well as
>>>> in `register` variables definitions.
>>>>
>>>> New tests pass.
>>>> Bootstrap pass.
>>>>
>>>> Is it ok for trunk?
>>>> Do we need to backport it to 4.8?
>>>>
>>>> gcc/
>>>> * config/i386/i386.h (ADDITIONAL_REGISTER_NAMES): Add
>>>> ymm and zmm register names.
>>>>
>>>> testsuite/
>>>> * gcc.target/i386/avx-additional-reg-names.c: New.
>>>> * gcc.target/i386/avx512f-additional-reg-names.c: Ditto.
>>
>>> Doesn't GCC generate the same code with xmm?
>>>
>>>> diff --git a/gcc/testsuite/gcc.target/i386/avx512f-additional-reg-names.c
>>>> b/gcc/testsuite/gcc.target/i386/avx512f-additional-reg-names.c
>>>> new file mode 100644
>>>> index 0000000..1bd428a
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.target/i386/avx512f-additional-reg-names.c
>>>> @@ -0,0 +1,9 @@
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-mavx512f" } */
>>>> +
>>>> +void foo ()
>>>> +{
>>>> + register int zmm_var asm ("zmm9");
>>>> +
>>>> + __asm__ __volatile__("vxorpd %%zmm0, %%zmm0, %%zmm7\n" : : : "zmm7" );
>>>> +}
>>>
>>> Doesn't GCC generate the same code with xmm?
>>
>> It does, but the situation is the same as with %eax vs. %rax names.
>> So, I think the patch is OK for mainline, and similar patch involving
>> only %ymm names for AVX-enabled branches.
>>
>
> If I want to write codes with asm statements which can
> be compiled with GCC 4.6 and above, I will use xmm
> instead of ymm. It makes ymm less attractive.
>
BTW, in glibc, there are
asm volatile ("vmovdqa64 %0, %%zmm0" : : "x" (zmm) : "xmm0" );
and
asm volatile ("vmovdqa %0, %%ymm0" : : "x" (ymm) : "xmm0" );
--
H.J.
