I theory the compiler could always statically inline a memcpy to a (possibly nop-padded) rep mov. Then the dynamic linker could dynamically patch the instructio

I theory the compiler could always statically inline a memcpy to a (possibly nop-padded) rep mov. Then the dynamic linker could dynamically patch the instructions to a call to an out of line function if rep mov is known not to be optimal to the actual CPU the code is running. The reverse (patching a call to memmove with a rep mov) is also possible.