[Bug tree-optimization/121279] [14/15/16 Regression] wrong code due to load of a bool from an union being pulled out of loop

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121279

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 62127
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62127&action=edit
untested patch

Needs the testcase added, a full bootstrap and some extra comments.
BUT it looks like it is doing the correct thing.