[Bug c++/83553] [6/7/8 Regression] compiler removes body of the for-loop, although there is a case label inside

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83553

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 42957
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42957&action=edit
gcc8-pr83553.patch

Untested fix.