gcc/testsuite/gcc.dg/builtin-arith-overflow-1.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2 -fdump-tree-optimized -g" } */
   3
   4 /* SUB_OVERFLOW should be folded into unsigned subtraction,
   5    because ovf is never used.  */
   6 __attribute__((noinline, noclone)) int
   7 fn1 (int x, unsigned int y)
   8 {
   9   int res;
  10   int ovf = __builtin_sub_overflow (x, y, &res);
  11   int res2 = res;
  12   int res3 = res2 - 2;
  13   (void) ovf;
  14   return res;
  15 }
  16
  17 /* MUL_OVERFLOW should be folded into unsigned multiplication,
  18    because ovf is never used.  */
  19 __attribute__((noinline, noclone)) int
  20 fn2 (signed char x, long int y)
  21 {
  22   short int res;
  23   int ovf = __builtin_mul_overflow (x, y, &res);
  24   int res2 = res;
  25   int res3 = res2 - 2;
  26   (void) ovf;
  27   return res;
  28 }
  29
  30 #if __SIZEOF_INT__ > __SIZEOF_SHORT__ && __SIZEOF_INT__ > 1
  31 /* ADD_OVERFLOW should be folded into unsigned addition,
  32    because it never overflows.  */
  33 __attribute__((noinline, noclone)) int
  34 fn3 (signed char x, unsigned short y, int *ovf)
  35 {
  36   int res;
  37   *ovf = __builtin_add_overflow (x, y, &res);
  38   return res;
  39 }
  40 #endif
  41
  42 /* MUL_OVERFLOW should be folded into unsigned multiplication,
  43    because it never overflows.  */
  44 __attribute__((noinline, noclone)) long int
  45 fn4 (long int x, long int y, int *ovf)
  46 {
  47   long int res;
  48   x &= 65535;
  49   y = (y & 65535) - 32768;
  50   *ovf = __builtin_mul_overflow (x, y, &res);
  51   return res;
  52 }
  53
  54 #if __SIZEOF_INT__ > 1
  55 /* MUL_OVERFLOW should be folded into unsigned multiplication,
  56    because it always overflows.  */
  57 __attribute__((noinline, noclone)) signed char
  58 fn5 (long int x, long int y, int *ovf)
  59 {
  60   signed char res;
  61   x = (x & 63) + (__SCHAR_MAX__ / 4);
  62   y = (y & 3) + 5;
  63   *ovf = __builtin_mul_overflow (x, y, &res);
  64   return res;
  65 }
  66 #endif
  67
  68 /* ADD_OVERFLOW should be folded into unsigned additrion,
  69    because it never overflows.  */
  70 __attribute__((noinline, noclone)) unsigned char
  71 fn6 (unsigned char x, unsigned char y, int *ovf)
  72 {
  73   unsigned char res;
  74   x = (x & 63) + ((unsigned char) ~0 - 66);
  75   y = (y & 3);
  76   *ovf = __builtin_add_overflow (x, y, &res);
  77   return res;
  78 }
  79
  80 /* ADD_OVERFLOW should be folded into unsigned additrion,
  81    because it always overflows.  */
  82 __attribute__((noinline, noclone)) unsigned char
  83 fn7 (unsigned char x, unsigned char y, int *ovf)
  84 {
  85   unsigned char res;
  86   x = (x & 15) + ((unsigned char) ~0 - 15);
  87   y = (y & 3) + 16;
  88   *ovf = __builtin_add_overflow (x, y, &res);
  89   return res;
  90 }
  91
  92 int
  93 main ()
  94 {
  95   int ovf;
  96   if (fn1 (-10, __INT_MAX__) != (int) (-10U - __INT_MAX__)
  97       || fn2 (0, 0) != 0
  98       || fn2 (32, 16383) != (short int) 524256ULL)
  99     __builtin_abort ();
 100 #if __SIZEOF_INT__ > __SIZEOF_SHORT__ && __SIZEOF_INT__ > 1
 101   if (fn3 (__SCHAR_MAX__, (unsigned short) ~0, &ovf) != (int) (__SCHAR_MAX__ + (unsigned short) ~0)
 102       || ovf
 103       || fn3 (-__SCHAR_MAX__ - 1, 0, &ovf) != (int) (-__SCHAR_MAX__ - 1)
 104       || ovf)
 105     __builtin_abort ();
 106 #endif
 107   if (fn4 (65535, 0, &ovf) != 65535L * -32768 || ovf)
 108     __builtin_abort ();
 109 #if __SIZEOF_INT__ > 1
 110   if (fn5 (0, 0, &ovf) != (signed char) (__SCHAR_MAX__ / 4 * 5)
 111       || !ovf
 112       || fn5 (63, 3, &ovf) != (signed char) ((__SCHAR_MAX__ / 4 + 63) * 8)
 113       || !ovf)
 114     __builtin_abort ();
 115 #endif
 116   if (fn6 (0, 0, &ovf) != (unsigned char) ~0 - 66
 117       || ovf
 118       || fn6 (63, 3, &ovf) != (unsigned char) ~0
 119       || ovf)
 120     __builtin_abort ();
 121   if (fn7 (0, 0, &ovf) != 0
 122       || !ovf
 123       || fn7 (63, 3, &ovf) != 18
 124       || !ovf)
 125     __builtin_abort ();
 126   return 0;
 127 }
 128
 129 /* { dg-final { scan-tree-dump-not "ADD_OVERFLOW" "optimized" } } */
 130 /* { dg-final { scan-tree-dump-not "SUB_OVERFLOW" "optimized" } } */
 131 /* { dg-final { scan-tree-dump-not "MUL_OVERFLOW" "optimized" } } */