Hi：

I implemented vectorization of the strlen function in the riscv64 architecture, which is controlled by __riscv_vector definition.Due to lack of support for risc-v V expansion in hardware, I conducted performance tests on a simulator, which was more than 10 times the performance achieved in C language. In terms of functionality, I tested the string length from 1 byte to 64 Mb, and the alignment of different addresses at the beginning of the string.

Please review it.I'm Looking forward to your reply,thanks.

Fei Zhang