[Dev-C++] loop optimization

[<or...@vp...>]

Hi!

Now, I have a question.
I need to do heavy optimizations in the project I am working on, and I 
am asking you, whether will I gain any speedup by optimizing loops. I am 
interested in the for loop exactly. Let's take this example:

for(i=0;i<getint();i++){
/* ... */
}

Would it worth it to take that getint() into an outer variable, and only 
use that in the conditional, like this:

int c = getint();
for(i=0;i<c;i++){
/* ... */
}

Will this give me any speedup? I am interested in particular, is for 
going to call getint() EVERY time in the first case (on top), or will it 
do it only once? I think the second case is better, am I right?

Allright, that was my first question, here is the second:
What is the case, if the conditional is a KNOWN value. Something, like a 
macro. Here is the example:

#define GETINT (10*5)

for(i=0;i<GETINT;i++){
/* ... */
}

I suppose, this will be optimised by the compiler, and this can even be 
unrolled, am I right?

Thanks in advance.
--
Greetings,
   Balázs