C++: Set bool value only if not set

Question

I have code in my C++ application that generally does this:

bool myFlag = false;
while (/*some finite condition unrelated to myFlag*/) {
    if (...) {
               


        

Answer 1

It is architecture specific whether if (!myFlag) myFlag = true; will take more time to execute than the simple myFlag = true; even without any optimization. There are architectures (e.g., https://developer.qualcomm.com/hexagon-processor) where both statements will take only one cycle each to execute.

The only way to figure out on your machine would be by measurement.

In any case myFlag = true will always be faster or have same execution time as if (!myFlag) myFlag = true;