[PATCH][X86] Add ISel patterns to select SSE3/AVX ADDSUB instructions.

[Andrea Di Biagio]

Committed revision 211427.
Thanks.

On Fri, Jun 20, 2014 at 10:34 PM, Andrea Di Biagio
<andrea.dibiagio at gmail.com> wrote:
> Hi Jim,
> Thanks for the review!
>
> On Fri, Jun 20, 2014 at 9:35 PM, Jim Grosbach <grosbach at apple.com> wrote:
>> This is excellent!
>>
>> Can you add a brief comment to the patch explaining the i32 constants in the input patterns and how they map to the masks?
>>
>> LGTM w/ that addition.
>
> Good point. I will add extra comments to explain the meaning of each
> constant used as a shuffle mask.
>
> -Andrea
>
>>
>> -Jim
>>
>>
>>> On Jun 17, 2014, at 7:41 AM, Andrea Di Biagio <andrea.dibiagio at gmail.com> wrote:
>>>
>>> Hi,
>>>
>>> this patch adds ISel patterns to select SSE3/AVX ADDSUB instructions
>>> from a sequence of "vadd + vsub + blend".
>>>
>>> Example:
>>>
>>> ///
>>> typedef float float4 __attribute__((ext_vector_type(4)));
>>>
>>> float4 foo(float4 A, float4 B) {
>>>  float4 X = A - B;
>>>  float4 Y = A + B;
>>>  return (float4){X[0], Y[1], X[2], Y[3]};
>>> }
>>> ///
>>>
>>> Before this patch, (with flag -mcpu=corei7) we produced the following
>>> assembly sequence:
>>>  movaps  %xmm0, %xmm2
>>>  addps   %xmm1, %xmm2
>>>  subps   %xmm1, %xmm0
>>>  blendps $10, %xmm2, %xmm0
>>>
>>>
>>> With this patch, we now produce a single
>>>  addsubps  %xmm1, %xmm0
>>>
>>> Please let me know if ok to commit.
>>>
>>> Thanks,
>>> Andrea Di Biagio.
>>> <patch-addsub.diff>
>>