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 "-fshow-column -Wsign-compare -fstrict-overflow" } */
   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 "9:different signedness" "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 when
  25      -fstrict-overflow is used.  */
  26   if (u < __builtin_abs(x))
  27     return x;
  28   if (__builtin_abs(x) < u)
  29     return x;
  30   if (u < (x ? __builtin_abs(x) : 10))
  31     return x;
  32   if ((x ? 10: __builtin_abs(x)) < u)
  33     return x;
  34
  35   /* A MODIFY_EXPR is non-negative if the new value is known to be
  36      non-negative.  */
  37   if (u < (x = -1)) /* { dg-warning "9:different signedness" "MODIFY_EXPR" } */
  38     return x;
  39   if (u < (x = 10))
  40     return x;
  41   if ((x = 10) < u)
  42     return x;
  43   if (u < (x = (y ? (x==y) : 10)))
  44     return x;
  45   if ((x = (y ? 10 : (x==y))) < u)
  46     return x;
  47
  48   return 0;
  49 }