[Bug c++/71372] [6/7 Regression] C++ FE drops TREE_THIS_VOLATILE in cp_fold on all tcc_reference trees

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71372

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 38623
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38623&action=edit
gcc7-pr71372.patch

Patch I'm going to bootstrap/regtest.