llvm-gcc-4.2/gcc/testsuite/gcc.c-torture/execute/builtins/lib/stpcpy.c

extern void abort (void);
extern int inside_main;

char *
stpcpy (char *dst, const char *src)
{
#ifdef __OPTIMIZE__
  if (inside_main)
    abort ();
#endif

  while (*src != 0)
    *dst++ = *src++;

  *dst = 0;
  return dst;
}