gcc/testsuite/gcc.dg/pr49120.c

/* PR c/49120 */
/* { dg-do compile } */
/* { dg-options "-Wall" } */
/* { dg-require-effective-target alloca } */

int
main ()
{
  int a = 1;
  int c = ({ char b[a + 1]; b[0] = 0; b[0]; });
  return c;
}