Re: [PATCH 2/4 v2][AArch64] Add support for FCCMP

[Evandro Menezes <e.menezes@samsung.com>]

Hi, James.

On 01/21/16 03:24, James Greenhalgh wrote:
> On Wed, Jan 06, 2016 at 02:44:47PM -0600, Evandro Menezes wrote:
>> On 01/06/2016 06:04 AM, Wilco Dijkstra wrote:
>>>> Here's what I had in mind when I inquired about distinguishing FCMP from
>>>> FCCMP.  As you can see in the patch, Exynos is the only target that
>>>> cares about it, but I wonder if ThunderX or Xgene would too.
>>>>
>>>> What do you think?
>>> The new attributes look fine (I've got a similar outstanding change), however
>>> please don't add them to non-AArch64 cores. We only need it for thunderx.md,
>>> cortex-a53.md, cortex-a57.md, xgene1.md and exynos-m1.md.
>>          Add support for the FCCMP insn types
>>
>>          2016-01-04  Evandro Menezes  <e.menezes@samsung.com>
>>
>>          gcc/
>>              * config/aarch64/aarch64.md (fccmp): Change insn type.
>>              (fccmpe): Likewise.
>>              * config/aarch64/thunderx.md (thunderx_fcmp): Add
>>     "fccmp{s,d}" types.
>>              * config/arm/cortex-a53.md (cortex_a53_fpalu): Likewise.
>>              * config/arm/cortex-a57.md (cortex_a57_fp_cmp): Likewise.
>>              * config/arm/xgene1.md (xgene1_fcmp): Likewise.
>>              * config/arm/exynos-m1.md (exynos_m1_fp_ccmp): New insn
>>     reservation.
>>              * config/arm/types.md (fccmps): Add new insn type.
>>              (fccmpd): Likewise.
>>
>> Got it.  Here's an updated patch.  Again, assuming that your
>> original patch is in place.  Perhaps you can build on it.
> If we don't have any targets which care about the fccmps/fccmpd split in
> the code base, do we really need it? Can we just follow the example of
> fcsel?

The Exynos M1 does care about the difference between FCMP and FCCMP, as 
can be seen in the patch.

>> diff --git a/gcc/config/arm/types.md b/gcc/config/arm/types.md
>> index 321ff89..daf7162 100644
>> --- a/gcc/config/arm/types.md
>> +++ b/gcc/config/arm/types.md
>> @@ -70,6 +70,7 @@
>>   ; f_rint[d,s]        double/single floating point rount to integral.
>>   ; f_store[d,s]       double/single store to memory.  Used for VFP unit.
>>   ; fadd[d,s]          double/single floating-point scalar addition.
>> +; fccmp[d,s]         double/single floating-point conditional compare.
> Can we follow the convention fcsel uses of calling out "From ARMv8-A:"
> for this type?
>

I'm not sure I follow.  Though I didn't refer to the ISA spec, I used 
the description from it for the *fccmp* type.

Please, advise.

-- 
Evandro Menezes