[Bug target/117205] RISC-V: Redundant vector memcpy loop

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117205

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2024-10-18

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
We handle the initializer as

     arr = *.LC0;
      D.129142 = __riscv_vle8_v_u8m1 (&arr, 32);
      return D.129142;

and since __riscv_vle8_v_u8m1 is a black box to GIMPLE constant folding
cannot see through this initializer.  The init loop is produced by
RTL expansion then and too difficult to elide later.

Intrinsics like this are bad for optimization.