gcc/testsuite/gcc.dg/uninit-pred-12.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O -Wmaybe-uninitialized -fdump-tree-uninit1" } */
   3
   4 extern unsigned bar (void);
   5 extern void quux (void);
   6 int z;
   7 unsigned foo (unsigned v, int y, int w)
   8 {
   9   unsigned u;
  10   if (v != 1)
  11     u = bar ();
  12
  13   // Prevent the "dom" pass from changing the CFG layout based on the inference
  14   // 'if (v != 1) is false then (v != 2) 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   // This variantion from uninit-pred-11.c caused compute_control_dep_chain
  20   // to run into a defect, producing z != 0 && v != 1, omitting !(i<10)
  21   // from the path predicate
  22   if (w)
  23     {
  24       if (y)
  25         z = 1;
  26       if (v != 1)
  27         return u;       /* { dg-bogus "may be used uninitialized" } */
  28     }
  29
  30   return 0;
  31 }
  32
  33 /* Make sure predicate analysis picked up the loop exit condition.  */
  34 /* { dg-final { scan-tree-dump "AND \\(NOT \\((ivtmp|doloop)" "uninit1" } } */