[Bug middle-end/106819] [13 Regression] NaN != NaN comparisons return false at -O2 since r13-2338

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106819

--- Comment #8 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Created attachment 53534
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53534&action=edit
Do not clobber signbit when unioning a NAN.

Untested patch to maintain signbit when unioning a NAN with another range.