[Bug target/120722] [16 Regression][gcn] ICE in gen_highpart, at emit-rtl.cc:1674 since r16-1565-g2dcc6dbd8a00ca when building libgcc/strub.c for gfx1036

[ams at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120722

--- Comment #2 from Andrew Stubbs <ams at gcc dot gnu.org> ---
Previously simplify_gen_subreg worked with this pattern:

(reg:DI 106 vcc_lo [orig:693 loop_mask_26 ] [693])

gave

(subreg:SI (reg:DI 106 vcc_lo [orig:693 loop_mask_26 ] [693]) 4)

Now it fails.