[Bug rtl-optimization/78546] [6/7 Regression] wrong code at -O2 and above

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78546

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 40174
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40174&action=edit
gcc7-pr78546.patch

Untested fix for 2), i.e. the wrong-code bug.  For 1), i.e. the optimization
regression, I think it should be tracked in a separate PR.