[Bug tree-optimization/69820] [6 Regression] Test miscompiled with -O3 option

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69820

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 37694
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37694&action=edit
gcc6-pr69820.patch

As for the ICE, the following patch works for me.  VI_512 iterator is only used
in the vcond* patterns, therefore it is desirable to change them all this way.