[Bug target/117953] [15 Regression] GCC miscompile rvv intrinsics at `-O2` and `-O3`, missing `csrwi` to modify `vxrm`

[rvismith1115 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117953

--- Comment #1 from rvismith <rvismith1115 at gmail dot com> ---
Here are results of array b I get (by gcc 15 + qemu 9.1.0):
at -O0 (correct)
>>> 0 2 5 7 10 12 15 17 20 22 
at -O3 (rounding error)
>>> 0 3 5 8 10 13 15 18 20 23