gomp-20050608-branch/gcc/testsuite/gcc.c-torture/execute/20040703-1.c

   1 /* PR 16341 */
   2
   3 #define PART_PRECISION (sizeof (cpp_num_part) * 8)
   4
   5 typedef unsigned int cpp_num_part;
   6 typedef struct cpp_num cpp_num;
   7 struct cpp_num
   8 {
   9    cpp_num_part high;
  10    cpp_num_part low;
  11    int unsignedp;  /* True if value should be treated as unsigned.  */
  12    int overflow;   /* True if the most recent calculation overflowed.  */
  13 };
  14
  15 static  int
  16 num_positive (cpp_num num, unsigned int precision)
  17 {
  18    if (precision > PART_PRECISION)
  19      {
  20        precision -= PART_PRECISION;
  21        return (num.high & (cpp_num_part) 1 << (precision - 1)) == 0;
  22      }
  23
  24    return (num.low & (cpp_num_part) 1 << (precision - 1)) == 0;
  25 }
  26
  27 static cpp_num
  28 num_trim (cpp_num num, unsigned int precision)
  29 {
  30    if (precision > PART_PRECISION)
  31      {
  32        precision -= PART_PRECISION;
  33        if (precision < PART_PRECISION)
  34          num.high &= ((cpp_num_part) 1 << precision) - 1;
  35      }
  36    else
  37      {
  38        if (precision < PART_PRECISION)
  39          num.low &= ((cpp_num_part) 1 << precision) - 1;
  40        num.high = 0;
  41      }
  42
  43    return num;
  44 }
  45
  46 /* Shift NUM, of width PRECISION, right by N bits.  */
  47 static cpp_num
  48 num_rshift (cpp_num num, unsigned int precision, unsigned int n)
  49 {
  50    cpp_num_part sign_mask;
  51    int x = num_positive (num, precision);
  52
  53    if (num.unsignedp || x)
  54      sign_mask = 0;
  55    else
  56      sign_mask = ~(cpp_num_part) 0;
  57
  58    if (n >= precision)
  59      num.high = num.low = sign_mask;
  60    else
  61      {
  62        /* Sign-extend.  */
  63        if (precision < PART_PRECISION)
  64          num.high = sign_mask, num.low |= sign_mask << precision;
  65        else if (precision < 2 * PART_PRECISION)
  66          num.high |= sign_mask << (precision - PART_PRECISION);
  67
  68        if (n >= PART_PRECISION)
  69          {
  70            n -= PART_PRECISION;
  71            num.low = num.high;
  72            num.high = sign_mask;
  73          }
  74
  75        if (n)
  76          {
  77            num.low = (num.low >> n) | (num.high << (PART_PRECISION - n));
  78            num.high = (num.high >> n) | (sign_mask << (PART_PRECISION - n));
  79          }
  80      }
  81
  82    num = num_trim (num, precision);
  83    num.overflow = 0;
  84    return num;
  85 }
  86                               #define num_zerop(num) ((num.low | num.high) == 0)
  87 #define num_eq(num1, num2) (num1.low == num2.low && num1.high == num2.high)
  88
  89 cpp_num
  90 num_lshift (cpp_num num, unsigned int precision, unsigned int n)
  91 {
  92    if (n >= precision)
  93      {
  94        num.overflow = !num.unsignedp && !num_zerop (num);
  95        num.high = num.low = 0;
  96      }
  97    else
  98      {
  99        cpp_num orig;
 100        unsigned int m = n;
 101
 102        orig = num;
 103        if (m >= PART_PRECISION)
 104          {
 105            m -= PART_PRECISION;
 106            num.high = num.low;
 107            num.low = 0;
 108          }
 109        if (m)
 110          {
 111            num.high = (num.high << m) | (num.low >> (PART_PRECISION - m));
 112            num.low <<= m;
 113          }
 114        num = num_trim (num, precision);
 115
 116        if (num.unsignedp)
 117          num.overflow = 0;
 118        else
 119          {
 120            cpp_num maybe_orig = num_rshift (num, precision, n);
 121            num.overflow = !num_eq (orig, maybe_orig);
 122          }
 123      }
 124
 125    return num;
 126 }
 127
 128 unsigned int precision = 64;
 129 unsigned int n = 16;
 130
 131 cpp_num num = { 0, 3, 0, 0 };
 132
 133 int main()
 134 {
 135    cpp_num res = num_lshift (num, 64, n);
 136
 137    if (res.low != 0x30000)
 138      abort ();
 139
 140    if (res.high != 0)
 141      abort ();
 142
 143    if (res.overflow != 0)
 144      abort ();
 145
 146    exit (0);
 147 }