[Bug target/79914] New: VEC_SELECT bugs in mips patterns

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79914

            Bug ID: 79914
           Summary: VEC_SELECT bugs in mips patterns
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

I've recently posted http://gcc.gnu.org/ml/gcc-patches/2017-03/msg00183.html
with some extra verification of sanity of md patterns (based on assertions
simplify-rtx.c does for VEC_SELECT as well as documentation requiring it).
With this patch make s-recog fails on mips-linux:
../../gcc/config/mips/mips-msa.md:1219:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1219:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1219:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1219:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1307:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1307:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1307:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1307:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1401:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1401:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1401:1: vec_select parallel with 2 elements,
expected 4                                                      
../../gcc/config/mips/mips-msa.md:1401:1: vec_select parallel with 2 elements,
expected 4