Just a silly short list sum script to provide as a baseline for benchmarking Swift code.

sumlist.c

// clang -O3 -march=native deleteme.c -o del_c

#include <stdio.h>
#include <time.h>
 
int main () {

	clock_t start, end;
	double cpu_time_used;
    int n[ 3000 ];
 
    for (int tests = 0; tests < 15; tests++) {
        start = clock();
		int sum = 0;
        for (int i = 0; i < 3000; i++) {
     	  n[i] = tests;
        }

		for(int i=0; i<3000; i++) {
			sum = sum + n[i];
		}

	    end = clock();
        cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
		printf("%.6f", cpu_time_used);
		printf(" %d", sum);
		printf("\n");
	}
    return 0;
}