示例#1
0
static bool
do_mpc_ckconv (real_value *result_real, real_value *result_imag,
	       mpc_srcptr m, bool inexact, const real_format *format)
{
  /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
     overflow/underflow occurred.  If -frounding-math, proceed iff the
     result of calling FUNC was exact.  */
  if (!mpfr_number_p (mpc_realref (m))
      || !mpfr_number_p (mpc_imagref (m))
      || mpfr_overflow_p ()
      || mpfr_underflow_p ()
      || (flag_rounding_math && inexact))
    return false;

  REAL_VALUE_TYPE tmp_real, tmp_imag;
  real_from_mpfr (&tmp_real, mpc_realref (m), format, GMP_RNDN);
  real_from_mpfr (&tmp_imag, mpc_imagref (m), format, GMP_RNDN);

  /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
     If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
     underflowed in the conversion.  */
  if (!real_isfinite (&tmp_real)
      || !real_isfinite (&tmp_imag)
      || (tmp_real.cl == rvc_zero) != (mpfr_zero_p (mpc_realref (m)) != 0)
      || (tmp_imag.cl == rvc_zero) != (mpfr_zero_p (mpc_imagref (m)) != 0))
    return false;

  real_convert (result_real, format, &tmp_real);
  real_convert (result_imag, format, &tmp_imag);

  return (real_identical (result_real, &tmp_real)
	  && real_identical (result_imag, &tmp_imag));
}
示例#2
0
/* Interpret TOKEN, a floating point number with FLAGS as classified
   by cpplib.  */
static tree
interpret_float (const cpp_token *token, unsigned int flags)
{
  tree type;
  tree value;
  REAL_VALUE_TYPE real;
  char *copy;
  size_t copylen;
  const char *type_name;

  /* FIXME: make %T work in error/warning, then we don't need type_name.  */
  if ((flags & CPP_N_WIDTH) == CPP_N_LARGE)
    {
      type = long_double_type_node;
      type_name = "long double";
    }
  else if ((flags & CPP_N_WIDTH) == CPP_N_SMALL
	   || flag_single_precision_constant)
    {
      type = float_type_node;
      type_name = "float";
    }
  else
    {
      type = double_type_node;
      type_name = "double";
    }

  /* Copy the constant to a nul-terminated buffer.  If the constant
     has any suffixes, cut them off; REAL_VALUE_ATOF/ REAL_VALUE_HTOF
     can't handle them.  */
  copylen = token->val.str.len;
  if ((flags & CPP_N_WIDTH) != CPP_N_MEDIUM)
    /* Must be an F or L suffix.  */
    copylen--;
  if (flags & CPP_N_IMAGINARY)
    /* I or J suffix.  */
    copylen--;

  copy = (char *) alloca (copylen + 1);
  memcpy (copy, token->val.str.text, copylen);
  copy[copylen] = '\0';

  real_from_string (&real, copy);
  real_convert (&real, TYPE_MODE (type), &real);

  /* Both C and C++ require a diagnostic for a floating constant
     outside the range of representable values of its type.  Since we
     have __builtin_inf* to produce an infinity, it might now be
     appropriate for this to be a mandatory pedwarn rather than
     conditioned on -pedantic.  */
  if (REAL_VALUE_ISINF (real) && pedantic)
    pedwarn ("floating constant exceeds range of %<%s%>", type_name);

  /* Create a node with determined type and value.  */
  value = build_real (type, real);
  if (flags & CPP_N_IMAGINARY)
    value = build_complex (NULL_TREE, convert (type, integer_zero_node), value);

  return value;
}
示例#3
0
文件: ubsan.c 项目: acoxepochlabs/gcc
tree
ubsan_instrument_float_cast (location_t loc, tree type, tree expr)
{
  tree expr_type = TREE_TYPE (expr);
  tree t, tt, fn, min, max;
  enum machine_mode mode = TYPE_MODE (expr_type);
  int prec = TYPE_PRECISION (type);
  bool uns_p = TYPE_UNSIGNED (type);

  /* Float to integer conversion first truncates toward zero, so
     even signed char c = 127.875f; is not problematic.
     Therefore, we should complain only if EXPR is unordered or smaller
     or equal than TYPE_MIN_VALUE - 1.0 or greater or equal than
     TYPE_MAX_VALUE + 1.0.  */
  if (REAL_MODE_FORMAT (mode)->b == 2)
    {
      /* For maximum, TYPE_MAX_VALUE might not be representable
	 in EXPR_TYPE, e.g. if TYPE is 64-bit long long and
	 EXPR_TYPE is IEEE single float, but TYPE_MAX_VALUE + 1.0 is
	 either representable or infinity.  */
      REAL_VALUE_TYPE maxval = dconst1;
      SET_REAL_EXP (&maxval, REAL_EXP (&maxval) + prec - !uns_p);
      real_convert (&maxval, mode, &maxval);
      max = build_real (expr_type, maxval);

      /* For unsigned, assume -1.0 is always representable.  */
      if (uns_p)
	min = build_minus_one_cst (expr_type);
      else
	{
	  /* TYPE_MIN_VALUE is generally representable (or -inf),
	     but TYPE_MIN_VALUE - 1.0 might not be.  */
	  REAL_VALUE_TYPE minval = dconstm1, minval2;
	  SET_REAL_EXP (&minval, REAL_EXP (&minval) + prec - 1);
	  real_convert (&minval, mode, &minval);
	  real_arithmetic (&minval2, MINUS_EXPR, &minval, &dconst1);
	  real_convert (&minval2, mode, &minval2);
	  if (real_compare (EQ_EXPR, &minval, &minval2)
	      && !real_isinf (&minval))
	    {
	      /* If TYPE_MIN_VALUE - 1.0 is not representable and
		 rounds to TYPE_MIN_VALUE, we need to subtract
		 more.  As REAL_MODE_FORMAT (mode)->p is the number
		 of base digits, we want to subtract a number that
		 will be 1 << (REAL_MODE_FORMAT (mode)->p - 1)
		 times smaller than minval.  */
	      minval2 = dconst1;
	      gcc_assert (prec > REAL_MODE_FORMAT (mode)->p);
	      SET_REAL_EXP (&minval2,
			    REAL_EXP (&minval2) + prec - 1
			    - REAL_MODE_FORMAT (mode)->p + 1);
	      real_arithmetic (&minval2, MINUS_EXPR, &minval, &minval2);
	      real_convert (&minval2, mode, &minval2);
	    }
	  min = build_real (expr_type, minval2);
	}
    }
  else if (REAL_MODE_FORMAT (mode)->b == 10)
    {
      /* For _Decimal128 up to 34 decimal digits, - sign,
	 dot, e, exponent.  */
      char buf[64];
      mpfr_t m;
      int p = REAL_MODE_FORMAT (mode)->p;
      REAL_VALUE_TYPE maxval, minval;

      /* Use mpfr_snprintf rounding to compute the smallest
	 representable decimal number greater or equal than
	 1 << (prec - !uns_p).  */
      mpfr_init2 (m, prec + 2);
      mpfr_set_ui_2exp (m, 1, prec - !uns_p, GMP_RNDN);
      mpfr_snprintf (buf, sizeof buf, "%.*RUe", p - 1, m);
      decimal_real_from_string (&maxval, buf);
      max = build_real (expr_type, maxval);

      /* For unsigned, assume -1.0 is always representable.  */
      if (uns_p)
	min = build_minus_one_cst (expr_type);
      else
	{
	  /* Use mpfr_snprintf rounding to compute the largest
	     representable decimal number less or equal than
	     (-1 << (prec - 1)) - 1.  */
	  mpfr_set_si_2exp (m, -1, prec - 1, GMP_RNDN);
	  mpfr_sub_ui (m, m, 1, GMP_RNDN);
	  mpfr_snprintf (buf, sizeof buf, "%.*RDe", p - 1, m);
	  decimal_real_from_string (&minval, buf);
	  min = build_real (expr_type, minval);
	}
      mpfr_clear (m);
    }
  else
    return NULL_TREE;

  if (flag_sanitize_undefined_trap_on_error)
    fn = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
  else
    {
      /* Create the __ubsan_handle_float_cast_overflow fn call.  */
      tree data = ubsan_create_data ("__ubsan_float_cast_overflow_data", NULL,
				     NULL, ubsan_type_descriptor (expr_type),
				     ubsan_type_descriptor (type), NULL_TREE);
      enum built_in_function bcode
	= flag_sanitize_recover
	  ? BUILT_IN_UBSAN_HANDLE_FLOAT_CAST_OVERFLOW
	  : BUILT_IN_UBSAN_HANDLE_FLOAT_CAST_OVERFLOW_ABORT;
      fn = builtin_decl_explicit (bcode);
      fn = build_call_expr_loc (loc, fn, 2,
				build_fold_addr_expr_loc (loc, data),
				ubsan_encode_value (expr, false));
    }

  t = fold_build2 (UNLE_EXPR, boolean_type_node, expr, min);
  tt = fold_build2 (UNGE_EXPR, boolean_type_node, expr, max);
  return fold_build3 (COND_EXPR, void_type_node,
		      fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, tt),
		      fn, integer_zero_node);
}