We have additional compiler options for optimization. These may include procedure inlining where performance may be improved, moving constants inside loops outside the loop, identify potential parallelism, include automatic vectorization or replace a division with a reciprocal and a multiplication if this speeds up the code.

c++  -O3 -c  mycode.cpp
c++  -O3 -o  mycode.exe  mycode.o

This (other options are -O2 or -Ofast) is the recommended option.