[Bug middle-end/88784] Middle end is missing some optimizations about unsigned

[ffengqi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88784

--- Comment #22 from Qi Feng <ffengqi at gcc dot gnu.org> ---
Two more similar ones:

x <= y  &&  x == ( 0 or XXX_MIN )         -->  x == ( 0 or XXX_MIN )
x >= y  &&  x == ( UXXX_MAX or XXX_MAX )  -->  x == ( UXXX_MAX or XXX_MAX )