gcc/testsuite/gcc.dg/tree-ssa/vrp77.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -fdump-tree-optimized" } */
   3
   4 #ifdef __SIZEOF_INT128__
   5 #define T __int128
   6 #else
   7 #define T long long
   8 #endif
   9
  10 extern void impossible (void);
  11
  12 void f(T x)
  13 {
  14   unsigned T y;
  15   unsigned T z;
  16   if (x < -7)
  17     return;
  18   if (x > 2)
  19     return;
  20   y = x;
  21   z = y * y;
  22   if (z == 666)
  23     impossible ();
  24 }
  25
  26 void g(unsigned T x)
  27 {
  28   unsigned T y;
  29   unsigned T z;
  30   unsigned T m = -1;
  31   m = m / 2;
  32   if (x < m-2)
  33     return;
  34   if (x > m-1)
  35     return;
  36   y = x;
  37   z = y * y;
  38   /* The product (ignoring it is a square) has only 3 possible values:
  39      4, 9 and 2^127+6.  At least one of the values 7, 666 and -666 is
  40      known to be impossible.  7 is the most logical in the current
  41      implementation.  */
  42   if (z == 7)
  43     impossible ();
  44 }
  45
  46 /* { dg-final { scan-tree-dump-not "impossible" "optimized" } } */
  47 /* { dg-final { cleanup-tree-dump "optimized" } } */