gcc/testsuite/gcc.dg/pr80788.c

/* PR tree-optimization/80788 */
/* { dg-do compile } */
/* { dg-options "-O2 -fwrapv" } */

void
foo (signed char x)
{
  signed char a = (x + 1) ^ 128;
  x &= !!a;
  if (x != 0)
    for (;;)
      ;
}