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Re: [i386] Scalar DImode instructions on XMM registers


2015-04-24 12:49 GMT+03:00 Uros Bizjak <ubizjak@gmail.com>:
> On Fri, Apr 24, 2015 at 11:45 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Fri, Apr 24, 2015 at 11:22 AM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
>>
>>> I was looking into PR65105 and tried to generate SSE computation for a
>>> simple 64bit  a + b + c sequence. Having no scalar integer instructions in
>>> SSE I have to use vector variants.
>>
>> Is this approach really better that having two add/addc instructions?
>
> FYI, V1DI mode was introduced because XMM shift insn were used to
> shift DImode values. The cost of moves from/to integer DImode reg pair
> was disastrous.
>
> Uros.

Does it mean I have to add V1DI instructions for all opcodes I want to
transform (add,sub,mul,or,and, etc.)?

Ilya


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