TCC on DOSBox

gistfile1.c

//
//  main.c
//  optimize
//
//  Created by Rodrigo Basa on 2014-05-29.
//  Copyright (c) 2014 Rodrigo Basa. All rights reserved.
//

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(int argc, const char * argv[]) {
	 const int samples = 30000;
	 clock_t lessifs = 0;
    clock_t orig = 0;
    clock_t moreifs = 0;
    clock_t start, end;
	 int i, w, x, f;
	 char z;

	 srand( (unsigned) time( NULL ) );


	 for ( i = 0; i < samples; i++ ) {
		  // Common set of data
		  w = rand() % 2;  // 0 or 1
		  x = rand() % 80;  // 0 to 80
		  f = rand() % 2;  // 0 or 1 converted to 'F' and 'M' below

		  if ( f == 1 )
				z = 'M';
		  else
				z = 'F';

		  //Original
		  start = clock();
		  if ( w == 1 ) {
				if ( z == 'M' ) {
					 if ( x >= 20 && x <= 65 ) {
						  // statements 1
					 } else if ( x < 20 ) {
						  // statements 3
					 }
				} else {
					 if ( x >= 20 ) {
						  if ( x <= 65 ) {
								// statements 1
								// statements 2
						  } else {
								// statements 2
						  }
					 }
				}
		  } else {
				if ( z == 'M' ) {
					 if ( x < 20 ) {
						  // statements 3
					 }
				} else {
					 if ( x >= 20 ) {
						  // statements 2
					 }
				}
		  }
		  end = clock();
		  orig += ( end - start );

		  // Less ifs, no nesting
		  // measure only the time spent in the conditional blocks
		  start = clock();
				if ( (w == 1) && (x >= 20) && (x <= 65) ) {
					 // no statements to isolate execution time of the conditional and comparisons
				}

				if ( (x >= 20) && (z == 'F') ) {
					 //
				}

				if ( (x < 20) && (z == 'M') ) {
					 //
				}
		  end = clock();
		  lessifs += ( end - start );

		  // More ifs, with nesting
		  // measure only the time spent in the conditional blocks
		  start = clock();
				if ( x < 20 ) {
					 if ( z == 'M' ) {
						  //
					 }
				} else {
					 if ( x <= 65 && w == 1 ) {
						  //
					 }
					 if ( z == 'F' ) {
						  //
					 }
				}
		  end = clock();
		  moreifs += ( end - start );
	 }
	 printf( "Original               : %f \n", orig/CLK_TCK );
	 printf( "Less ifs, no nesting   : %f \n" , lessifs/CLK_TCK );
	 printf( "More ifs, with nesting : %f \n" , moreifs/CLK_TCK );

	 return 0;
}