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  }