gcc/testsuite/gcc.dg/compare4.c

   1 /* Test for a bogus warning on comparison between signed and unsigned.
   2    Origin: Kaveh R. Ghazi <ghazi@caip.rutgers.edu> 5/13/2001.  */
   3
   4 /* { dg-do compile } */
   5 /* { dg-options "-Wsign-compare" } */
   6
   7 extern void bar(void);
   8
   9 int foo(int x, int y, unsigned u)
  10 {
  11   /* A COMPOUND_EXPR is non-negative if the last element is known to
  12      be non-negative.  */
  13   if (u < (bar(), -1)) /*{ dg-warning "signed and unsigned" "COMPOUND_EXPR" }*/
  14     return x;
  15   if (u < (bar(), 10))
  16     return x;
  17   if ((bar(), 10) < u)
  18     return x;
  19   if (u < (x ? (bar(),bar(),bar(),bar(),x==y) : 10))
  20     return x;
  21   if ((x ? 10 : (bar(),bar(),bar(),bar(),x==y)) < u)
  22     return x;
  23
  24   /* Test an ABS_EXPR, which is by definition non-negative.  */
  25   if (u < __builtin_abs(x))
  26     return x;
  27   if (__builtin_abs(x) < u)
  28     return x;
  29   if (u < (x ? __builtin_abs(x) : 10))
  30     return x;
  31   if ((x ? 10: __builtin_abs(x)) < u)
  32     return x;
  33
  34   /* A MODIFY_EXPR is non-negative if the new value is known to be
  35      non-negative.  */
  36   if (u < (x = -1)) /* { dg-warning "signed and unsigned" "MODIFY_EXPR" } */
  37     return x;
  38   if (u < (x = 10))
  39     return x;
  40   if ((x = 10) < u)
  41     return x;
  42   if (u < (x = (y ? (x==y) : 10)))
  43     return x;
  44   if ((x = (y ? 10 : (x==y))) < u)
  45     return x;
  46
  47   return 0;
  48 }