For H8/300 size_t is 32 bits wide, but (unsigned char)buf[2] << 16
promotes to int which is only 16 bits wide. The shift is then undefined.
This fixes it by converting to size_t before shifting.
libstdc++-v3/ChangeLog:
PR libstdc++/107885
* libsupc++/hash_bytes.cc (_Hash_bytes): Convert to size_t
instead of implicit integer promotion to 16 bits.
Jonathan Wakely
7b79fa9309