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  Forcing Functions To Be Called Non-inlined
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Occasionaly, one needs to call a function (usually small one) and make sure that it'll not be inlined. Often such little functions are auto-inlined by the optimizer, when compiling in release/optimized mode. Although there is a way to prevent function from inlining by prototyping it with the _cdecl keyword, sometimes all you need just specific calls to be non-inlined.

Here is the macro:

#define NON_INLINED_CALL(a) (((int)(a)+1)?(a):(0)) 



Now, by forcing some fake calculation (int(a)+1) we stop the compiler from optimzing given line, also by using v ? (a) : (0), we are forcing the compiler to use the _cdecl way of calling the function.

Example:

static int test(int a, int b, int c)
{
  return a*b*c;
}

#define NON_INLINED_CALL(a) (((int)(a)+1)?(a):(0))

extern int results[2]; extern int a, b, c; extern int d, e, f;

void test2( void ) { results[0] = test(a,b,c); // Eventually with good optimizations this will be inlined results[1] = NON_INLINED_CALL(test)(d,e,f); // No inlining here }



Under MSVC we can construct simple and faster macro

#define NON_INLINED_CALL_MSVC(a) ((a) ? (a) : 0) 

but the latter will not stop GCC optimizer, and we'll not get the results we wanted to.

P.S. I didn't test any other compilers - only GCC 2.99(ps2-ee one), and MSVC6.00


The zip file viewer built into the Developer Toolbox made use of the zlib library, as well as the zlibdll source additions.

 

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