[Bug target/70329] New: wrong code with -mavx512bw and 64byte vectors

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70329

            Bug ID: 70329
           Summary: wrong code with -mavx512bw and 64byte vectors
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
            Target: x86_64-pc-linux-gnu

Created attachment 38041
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38041&action=edit
reduced testcase

Output (using emulator):
$ gcc -mavx512bw testcase.c
$ sde64 -- ./a.out 
2
Aborted

$ gcc -v                    
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-234350-checking-yes-rtl-df-nographite/bin/../libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-checking=yes,rtl,df --without-cloog --without-ppl --without-isl
--disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-234350-checking-yes-rtl-df-nographite
Thread model: posix
gcc version 6.0.0 20160319 (experimental) (GCC) 

Tested revisions:
trunk r234350 - FAIL
5-branch r234210 - FAIL
4_9-branch - -mavx512bw is not recognised