C - huge arrays - Segmentation fault (core dumped)

I'm getting the error "Segmentation fault (core dumped)

Either of these approaches work if loops = 207500 or smaller. However if I increase this (e.g. 2100000) I get the error

#include 

void main()
{

  long i;
  long loops;

  loops = 2075000; // works
  loops = 2100000; // Segmentation fault (core dumped)

  if (1) {       
    int arr[loops]; // stack array
    for (i = 0; i < loops; i++) {
      arr[i] = 3;

    }
  }

  if (1) {
    int *arr = (int *) malloc(sizeof(int) * loops); // heap array
    for (i = 0; i < loops; i++) {
      arr[i] = 3;
    }
  }


}

I'm using Ubuntu 12.04 LTS via Virtual box with 8gb ram allocated