gcc/testsuite/gcc.dg/auto-init-uninit-26.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O -Wmaybe-uninitialized -ftrivial-auto-var-init=zero" } */
   3
   4 extern unsigned bar (void);
   5 extern void quux (void);
   6
   7 unsigned foo (unsigned v)
   8 {
   9   unsigned u;
  10   if (v != 100)
  11     u = bar ();
  12
  13   // Prevent the "dom" pass from changing the CFG layout based on the inference
  14   // 'if (v != 100) is false then (v < 105) is true'.  (Now it would have to
  15   // duplicate the loop in order to do so, which is deemed expensive.)
  16   for (int i = 0; i < 10; i++)
  17     quux ();
  18
  19   if (v < 105) /* v == 100 falls into this range.  */
  20     return u;       /* { dg-warning "may be used uninitialized" }  */
  21
  22   return 0;
  23 }