Thread: Do C compliers make "frequently called function" an inline function automatically?

So the question is -

Code:

//will this code runs slower-
for (int i = 0; i < strlen(str); i++)
{......}

//compare to this-

int length = strlen(str);
for (int i = 0; i < length; i++)
{.......}

Or our "MODERN & SMART" compliers will automatically make strlen() inline as it is inside loop?

I think this is the case with c++ compilers,isnt it ?

Why not put your code to the test, in your compiler? Enter a nice long string, and time it with clock()?

That's one of the best things about programming a computer, imo. You can test your idea's, ON YOUR SYSTEM, and with your own compiler, and answer the question authoritatively, in many cases.

I'm a big fan of using the second version. Why rely on the compiler to do simple things?

Or you could compile and check the assembly output to compare.