https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98856
--- Comment #28 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Uroš Bizjak from comment #27)
> (In reply to Richard Biener from comment #26)
> > but that doesn't seem to match for some unknown reason.
> Try this:
The latency problem with the original testcase is solved with:
(define_peephole2
[(match_scratch:DI 3 "Yv")
(set (match_operand:V2DI 0 "sse_reg_operand")
(vec_concat:V2DI (match_operand:DI 1 "sse_reg_operand")
(match_operand:DI 2 "nonimmediate_gr_operand")))]
""
[(set (match_dup 3) (match_dup 2))
(set (match_dup 0)
(vec_concat:V2DI (match_dup 1) (match_dup 3)))])
but I don't know if this transformation applies universally to all x86 targets.
