gcc/testsuite/gcc.c-torture/execute/20040703-1.c

   1 /* PR 16341 */
   2 /* { dg-require-effective-target int32plus } */
   3
   4 #define PART_PRECISION (sizeof (cpp_num_part) * 8)
   5
   6 typedef unsigned int cpp_num_part;
   7 typedef struct cpp_num cpp_num;
   8 struct cpp_num
   9 {
  10    cpp_num_part high;
  11    cpp_num_part low;
  12    int unsignedp;  /* True if value should be treated as unsigned.  */
  13    int overflow;   /* True if the most recent calculation overflowed.  */
  14 };
  15
  16 static  int
  17 num_positive (cpp_num num, unsigned int precision)
  18 {
  19    if (precision > PART_PRECISION)
  20      {
  21        precision -= PART_PRECISION;
  22        return (num.high & (cpp_num_part) 1 << (precision - 1)) == 0;
  23      }
  24
  25    return (num.low & (cpp_num_part) 1 << (precision - 1)) == 0;
  26 }
  27
  28 static cpp_num
  29 num_trim (cpp_num num, unsigned int precision)
  30 {
  31    if (precision > PART_PRECISION)
  32      {
  33        precision -= PART_PRECISION;
  34        if (precision < PART_PRECISION)
  35          num.high &= ((cpp_num_part) 1 << precision) - 1;
  36      }
  37    else
  38      {
  39        if (precision < PART_PRECISION)
  40          num.low &= ((cpp_num_part) 1 << precision) - 1;
  41        num.high = 0;
  42      }
  43
  44    return num;
  45 }
  46
  47 /* Shift NUM, of width PRECISION, right by N bits.  */
  48 static cpp_num
  49 num_rshift (cpp_num num, unsigned int precision, unsigned int n)
  50 {
  51    cpp_num_part sign_mask;
  52    int x = num_positive (num, precision);
  53
  54    if (num.unsignedp || x)
  55      sign_mask = 0;
  56    else
  57      sign_mask = ~(cpp_num_part) 0;
  58
  59    if (n >= precision)
  60      num.high = num.low = sign_mask;
  61    else
  62      {
  63        /* Sign-extend.  */
  64        if (precision < PART_PRECISION)
  65          num.high = sign_mask, num.low |= sign_mask << precision;
  66        else if (precision < 2 * PART_PRECISION)
  67          num.high |= sign_mask << (precision - PART_PRECISION);
  68
  69        if (n >= PART_PRECISION)
  70          {
  71            n -= PART_PRECISION;
  72            num.low = num.high;
  73            num.high = sign_mask;
  74          }
  75
  76        if (n)
  77          {
  78            num.low = (num.low >> n) | (num.high << (PART_PRECISION - n));
  79            num.high = (num.high >> n) | (sign_mask << (PART_PRECISION - n));
  80          }
  81      }
  82
  83    num = num_trim (num, precision);
  84    num.overflow = 0;
  85    return num;
  86 }
  87                               #define num_zerop(num) ((num.low | num.high) == 0)
  88 #define num_eq(num1, num2) (num1.low == num2.low && num1.high == num2.high)
  89
  90 cpp_num
  91 num_lshift (cpp_num num, unsigned int precision, unsigned int n)
  92 {
  93    if (n >= precision)
  94      {
  95        num.overflow = !num.unsignedp && !num_zerop (num);
  96        num.high = num.low = 0;
  97      }
  98    else
  99      {
 100        cpp_num orig;
 101        unsigned int m = n;
 102
 103        orig = num;
 104        if (m >= PART_PRECISION)
 105          {
 106            m -= PART_PRECISION;
 107            num.high = num.low;
 108            num.low = 0;
 109          }
 110        if (m)
 111          {
 112            num.high = (num.high << m) | (num.low >> (PART_PRECISION - m));
 113            num.low <<= m;
 114          }
 115        num = num_trim (num, precision);
 116
 117        if (num.unsignedp)
 118          num.overflow = 0;
 119        else
 120          {
 121            cpp_num maybe_orig = num_rshift (num, precision, n);
 122            num.overflow = !num_eq (orig, maybe_orig);
 123          }
 124      }
 125
 126    return num;
 127 }
 128
 129 unsigned int precision = 64;
 130 unsigned int n = 16;
 131
 132 cpp_num num = { 0, 3, 0, 0 };
 133
 134 int main()
 135 {
 136    cpp_num res = num_lshift (num, 64, n);
 137
 138    if (res.low != 0x30000)
 139      abort ();
 140
 141    if (res.high != 0)
 142      abort ();
 143
 144    if (res.overflow != 0)
 145      abort ();
 146
 147    exit (0);
 148 }