The implementation in `riscv64/dot.c` fails the `test_dsdot` test, and the generic kernel seems to have better precision. Tested on SiFive FU740 (HiFive Unmatched) and QEMU. Also see #1469.
e.g. make CC=riscv64-unknown-linux-gnu-gcc FC=riscv64-unknown-linux-gnu-gfortran TARGET=RISCV64_GENERIC HOSTCC=gcc