gcc/testsuite/gcc.dg/uninit-pr90394-1-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   /* The warning is not bogus, because (5 & 3) != 0 and therefore if v == 5,
   8      the value of undef is used without being initialized.  */
   9   unsigned int undef;        /* { dg-warning "may be used uninitialized" } */
  10   unsigned int _2;
  11   unsigned int _9;
  12   unsigned int _10;
  13   unsigned pred;
  14
  15   __BB(2):
  16   if (v_4(D) != 5u)
  17     goto __BB3;
  18   else
  19     goto __BB4;
  20
  21   /* 'undef' is defined conditionally (under 'v != 5' predicate)  */
  22   __BB(3):
  23   undef_8 = 8u;
  24   goto __BB4;
  25
  26   /* An undef value flows into a phi.  */
  27   __BB(4):
  28   undef_1 = __PHI (__BB2: undef_5(D), __BB3: undef_8);
  29   pred = v_4(D) & 3u;
  30   if (pred != 0u)
  31     goto __BB5;
  32   else
  33     goto __BB6;
  34
  35   /* The phi value is used here (under 'v & 3' predicate).  */
  36   __BB(5):
  37   _9 = undef_1;
  38   goto __BB7;
  39
  40   __BB(6):
  41   _10 = v_4(D);
  42   goto __BB7;
  43
  44   __BB(7):
  45   _2 = __PHI (__BB5: _9, __BB6: _10);
  46   return _2;
  47 }