Variable Length Arrays in C

Makefile

all: var_len_arrays.c
	gcc -O1 var_len_arrays.c -S

var_len_arrays.c

#include <stdio.h>

void __attribute__ ((noinline)) exercise(int *arr, int n) {
    int i;
    for (i = 1; i < n; ++i) {
        arr[i] = arr[i - 1] ^ arr[i];
    }
}

void foo() {
    int arr[10];
    arr[3] = 1234;
    exercise(arr, 10);
}

void bar() {
    int arr[10];
    int brr[12];
    arr[3] = 1234;
    brr[3] = 5678;
    exercise(arr, 10);
    exercise(brr, 12);
}

void baz(int n) {
    int arr[n];
    arr[3] = 1234;
    exercise(arr, n);
}

void bam(int n) {
    int arr[n];
    int brr[n];
    int crr[n];
    int drr[n];
    int err[n];
    int frr[n];
    int grr[n];
    int hrr[n];
    int irr[n];
    int jrr[n];
    int krr[n];
    int rrr[n];
    arr[3] = 1234;
    brr[3] = 1234;
    crr[3] = 1234;
    drr[3] = 1234;
    err[3] = 1234;
    frr[3] = 1234;
    grr[3] = 1234;
    hrr[3] = 1234;
    irr[3] = 1234;
    jrr[3] = 1234;
    krr[3] = 1234;
    rrr[3] = 1234;
    exercise(arr, n);
    exercise(brr, n);
    exercise(crr, n);
    exercise(drr, n);
    exercise(err, n);
    exercise(frr, n);
    exercise(grr, n);
    exercise(hrr, n);
    exercise(irr, n);
    exercise(jrr, n);
    exercise(krr, n);
    exercise(rrr, n);
}

int main(int argc, char *argv[]) {
    printf("Ok!\n");
    return 0;
}

Blog post explaining this code: https://scvalex.net/posts/40/