1 /* Narrow floating-point values to their semantic type. 2 Copyright (C) 2015-2022 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