gcc/testsuite/gcc.dg/uninit-29-gimple.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-fgimple -O -Wmaybe-uninitialized" } */
   3
   4 unsigned int __GIMPLE (ssa,startwith("uninit1"))
   5 foo (unsigned int v)
   6 {
   7   unsigned int undef;        /* { dg-warning "may be used uninitialized" } */
   8   unsigned int _2;
   9   unsigned int _9;
  10   unsigned int _10;
  11   unsigned pred;
  12
  13   __BB(2):
  14   pred = v_4(D) & 3u;
  15   if (pred != 0u)
  16     goto __BB3;
  17   else
  18     goto __BB4;
  19
  20   /* 'undef' is defined conditionally (under 'v & 3' predicate)  */
  21   __BB(3):
  22   undef_8 = 8u;
  23   goto __BB4;
  24
  25   /* An undef value flows into a phi.  */
  26   __BB(4):
  27   undef_1 = __PHI (__BB2: undef_5(D), __BB3: undef_8);
  28   if (v_4(D) != 16u)
  29     goto __BB5;
  30   else
  31     goto __BB6;
  32
  33   /* The phi value is used here (under 'v != 16' predicate).  */
  34   __BB(5):
  35   _9 = undef_1;
  36   goto __BB7;
  37
  38   __BB(6):
  39   _10 = v_4(D);
  40   goto __BB7;
  41
  42   __BB(7):
  43   _2 = __PHI (__BB5: _9, __BB6: _10);
  44   return _2;
  45 }