[Bug tree-optimization/125641] `a>>signbit | a` is just `max`

[kaelfandrew at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125641

--- Comment #3 from Kael Franco <kaelfandrew at gmail dot com> ---
Created attachment 64663
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=64663&action=edit
Untested patch