[Bug c++/69797] [4.9/5/6 Regression] ICE on invalid code on x86_64-linux-gnu in operator[], at vec.h:714

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69797

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 37693
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37693&action=edit
gcc6-pr69797.patch

Untested fix.