소스코드 부분 최적

https://twitter.com/MittringMartin/status/912817354827907073

Visual studio :
#pragma optimize( "", off )
 ..code..
#pragma optimize( "", on )


GCC 44.4 and up:
https://news.ycombinator.com/item?id=4711571

#pragma GCC push_options
#pragma GCC optimize ("O0")

memset(a, 0, 3); // .. code ..

#pragma GCC pop_options