compilation - if 0 is compiled in c program -

i'm trying removed unused code program - can't delete code now, want disable start.

let's have following code:

if (cond){   dosomething() } 

and cond false dosomething never called.

i want like:

#define remove_unused_code 0 if (cond && remove_unused_code){   dosomething() } 

now obvious (and compiler) code unused.

will compiler remove if condition or leave , never in?

p.s.: can't use #if 0 purpose

gcc explicitly remove conditional blocks have constant expression controlling them, , the gnu coding standards explicitly recommend take advantage of this, instead of using cruder methods such relying on preprocessor. although using preprocessor #if may seem more efficient because removes code @ earlier stage, in practice modern optimizers work best when give them information possible (and of course makes program cleaner , more consistent if can avoid adding phase-separation dependency @ point isn't necessary).

decisions very, very easy modern compiler make - simplistic tcc perform amount of dead-code elimination; powerful systems llvm , gcc spot this, , more complex cases you, human reader, might miss (by tracing lifetime , modification of variables beyond looking @ single points).

this in addition other advantages of full compilation, fact code within if checked errors (whereas #if more useful removing code would be erroneous on current system, references nonexistent platform functions).