[Bug target/99808] [8/9/10/11 Regression] ICE in as_a, at machmode.h:365

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99808

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The bug is clearly on the aarch64 backend side,
(insn 7 6 8 (set (reg/v:V2DF 73 [ arg2 ])
        (vec_concat:V2DF (reg:DF 75)
            (const_int 0 [0]))) "pr99808.c":9 -1
     (nil))

(insn 8 7 0 (set (reg/v:V2DF 73 [ arg2 ])
        (vec_concat:V2DF (vec_select:DF (reg/v:V2DF 73 [ arg2 ])
                (parallel:V2DF [
                        (const_int 0 [0])
                    ]))
            (reg:DF 76))) "pr99808.c":9 -1
     (nil))
is IMNSHO invalid RTL in both cases.  const0_rtx is not valid constant for
DFmode.