[Bug middle-end/120721] [16 regression] ICE when building llvm-20.1.7 on arm64 (instantiate_virtual_regs_in_insn, at function.cc:1737)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120721

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
aarch64_expand_vector_init_fallback seems to be creating a V2DImode subreg from
DImode 24626                  rtx x = force_reg (inner_mode, XVECEXP (vals, 0,
maxelement));
24627                 aarch64_emit_move (target, lowpart_subreg (mode, x,
inner_mode));
where vals is
(parallel:V2DI [
        (reg/f:DI 95 virtual-incoming-args [ _30 ])
        (reg:DI 118 [ _43 ])
    ])