https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114801
--- Comment #3 from Christophe Lyon <clyon at gcc dot gnu.org> --- lowpart_subreg does not work either. If we put the predicates in a variable in the testcase, then in function_expander::add_input_operand() x is already a (subreg/s/v:HI (reg:SI 116 [ _3 ]) 0) so taking gen_lowpart of that is OK (we just want HImode to get the 16 bits of predicates). But when predicates are passed as a constant as in the testcase, we have x = (const_int -13108 [0xffffffffffffcccc]) and gen_lowpart (HImode, x) fails on that. I'm trying an approach to convert the constant into a vector of constants whose mode will V4BImode in this case.
