[Bug rtl-optimization/56766] Fails to combine (vec_select (vec_concat ...)) to (vec_merge ...)

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56766

--- Comment #19 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Segher Boessenkool from comment #18)
> (in reply to c#9)
> 
> Yes, this is a generic problem.  recog will not recognise patterns
> where regs are swapped in some places but not others.  This can of
> course be worked around in combine, but that will be expensive (and
> not solve the real problem).

So, do you think the patch in Comment #15 is the way to go at this time?