[Bug other/70078] gccint: define_split "not" allowed to create pseudos

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70078

--- Comment #2 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
(I'll make a patch with these and some more corrections once it's clear how the
wording should be.)