gcc/testsuite/gcc.dg/ubsan/pr81505.c

/* { dg-do compile } */
/* { dg-options "-O3 -fsanitize=signed-integer-overflow" } */

int a, b, c, h;

int i[5][5];

void
fn1 ()
{
  int l = 0;

  for (a = 0; a <= 3; a++)
    for (b = 1; b >= 0; b -= 1)
      l |= i[0][b];
  c = l;
}