I386.md: *_mixed and *_sse

[Uros Bizjak]

Hello!

> From i386.md, alternative 1 of *fop_sf_comm_mixed is duplicated with
> *fop_sf_comm_sse. Why do we define a _mixed pattern here?
>
> (define_insn "*fop_sf_comm_mixed"
>   [(set (match_operand:SF 0 "register_operand" "=f,x")
> 	(match_operator:SF 3 "binary_fp_operator"

Register allocator is free to choose either x87 or SSE register in
_mixed case, where only SSE reg alternative is available in _sse
pattern.

Uros.