SingleSource/Regression/C/DuffsDevice.c

/* This silly testcase is here to check that "Duff's Device" works properly
 * in LLVM.  Guess what, it does.  :)
 *
 * For more info, see: http://www.lysator.liu.se/c/duffs-device.html
 */

#include <stdio.h>

	sum(to, from, count)
	register short *to, *from;
	register count;
	{
		register n=(count+7)/8;
		switch(count%8){
		case 0:	do{	*to += *from++;
		case 7:		*to += *from++;
		case 6:		*to += *from++;
		case 5:		*to += *from++;
		case 4:		*to += *from++;
		case 3:		*to += *from++;
		case 2:		*to += *from++;
		case 1:		*to += *from++;
			}while(--n>0);
		}
	}

int main() {
	short Array[100];
	short Sum = 0;
	int i;

	for (i = 0; i != 100; ++i)
		Array[i] = i;

	sum(&Sum, Array, 100);

	printf("Sum is %d\n", Sum);
        return 0;
}