On 1/11/19 4:03 AM, Cao jin wrote: > Now the questions is: from code-reading, it is kind of non-intuitive, is > there any explicit way to control the optimization behavior accurately? Hi. Please take a look here: https://gcc.gnu.org/onlinedocs/gcc.pdf you are searching for: -mmemcpy -mno-memcpy Force (do not force) the use of memcpy for non-trivial block moves. The default is ‘-mno-memcpy’, which allows GCC to inline most constant-sized copies and possibly for: -mmemcpy-strategy and -mstringop-strategy=alg Martin
