gcc/testsuite/gcc.dg/m-un-1.c

   1 /* m-un-1.c: "un" for "uninitialized" */
   2
   3 /*
   4 From: Jim Wilson <wilson@cygnus.com>
   5 Date: Wed, 6 Jul 1994 13:11:47 -0700
   6 To: dje@cygnus.com
   7 Subject: Re: devo/gcc ChangeLog.fsf stmt.c
   8 Cc: cvs-gcc@cygnus.com, tege@cygnus.com
   9
  10         How about a test case?  :-)
  11
  12 Compile with -O -Wall and the broken compiler gives you:
  13 tmp.c:6: warning: `k' might be used uninitialized in this function
  14 The fixed compiler (and gcc 2.5.8) gives no warning.
  15
  16 This happens to fix a performance regression in the code generated for
  17 while loops, but that is presumably much much harder to test for.
  18 */
  19
  20 /* { dg-do compile } */
  21 /* { dg-options "-O -Wall" } */
  22
  23 int
  24 sub ()
  25 {
  26   int i = 0;
  27   int j = 0;
  28   int k;        /* { dg-bogus "`k' might be used uninitialized" "uninitialized warning regression" } */
  29
  30   while (i == 0 && j == 0)
  31     {
  32       k = 10;
  33       i = sub ();
  34     }
  35
  36   return k;
  37 }