[Bug target/97042] powerpc64 UINT_MAX constant

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97042

--- Comment #8 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Alan Modra from comment #7)
> and of course, li 0xffff is li -1 which sets all bits.

Erm, yes.  Duh.

So that g:5d3ae76af13 splitter should not fire for numbers that fit in
32 bits but that have the high bit of both 16-bit halfs set.