[Bug target/93178] PPC: inefficient 64-bit constant generation if msb is off in low 16 bit

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93178

--- Comment #3 from Segher Boessenkool <segher at gcc dot gnu.org> ---
The code at
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/rs6000/rs6000.c;h=fc36bb6714b2a4c922e903e2ebe333c6bdaeefcd;hb=HEAD#l9229
does not treat this case specially, but it should.