[Bug rtl-optimization/123822] [15/16 Regression] ICE: in gen_rtx_SUBREG, at emit-rtl.cc:1032 at -Ofast with _Decimal64 vector

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123822

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2026-01-26

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So we go from:
Trying 50, 51 -> 56:
   50: r139:V2DI=const_vector
   51: r139:V2DI=vec_merge(vec_duplicate(r145:DI),r139:V2DI,0x2)
      REG_DEAD r145:DI
   56: v1:DD=r139:V2DI#0
To:
(subreg:DD (vec_concat:V2DI (const_int -1 [0xffffffffffffffff])
        (reg:DI 145 [ _22 ])) 0)

And then try to simplify that but that causes an ICE.