1/* Narrow floating-point values to their semantic type.
2 Copyright (C) 2015-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _MATH_NARROW_EVAL_H
20#define _MATH_NARROW_EVAL_H 1
21
22#include <float.h>
23
24/* math_narrow_eval reduces its floating-point argument to the range
25 and precision of its semantic type. (The original evaluation may
26 still occur with excess range and precision, so the result may be
27 affected by double rounding.) */
28#if FLT_EVAL_METHOD == 0
29# define math_narrow_eval(x) (x)
30#else
31# if FLT_EVAL_METHOD == 1
32# define excess_precision(type) __builtin_types_compatible_p (type, float)
33# else
34# define excess_precision(type) (__builtin_types_compatible_p (type, float) \
35 || __builtin_types_compatible_p (type, \
36 double))
37# endif
38# define math_narrow_eval(x) \
39 ({ \
40 __typeof (x) math_narrow_eval_tmp = (x); \
41 if (excess_precision (__typeof (math_narrow_eval_tmp))) \
42 __asm__ ("" : "+m" (math_narrow_eval_tmp)); \
43 math_narrow_eval_tmp; \
44 })
45#endif
46
47#endif /* math-narrow-eval.h */
48