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glibc/math/math-underflow.h
Adhemerval Zanella 39bf95c1ba math: Suppress clang -Wabsolute-value warning on math_check_force_underflow
clang warns:

  ../sysdeps/x86/fpu/powl_helper.c:233:3: error: absolute value function
  '__builtin_fabsf' given an argument of type 'typeof (res)' (aka 'long
  double') but has parameter of type 'float' which may cause truncation of
  value [-Werror,-Wabsolute-value]
    math_check_force_underflow (res);
    ^
  ./math-underflow.h:45:11: note: expanded from macro
  'math_check_force_underflow'
        if (fabs_tg (force_underflow_tmp)                         \
            ^
  ./math-underflow.h:27:20: note: expanded from macro 'fabs_tg'
  #define fabs_tg(x) __MATH_TG ((x), (__typeof (x)) __builtin_fabs, (x))
                     ^
  ../math/math.h:899:16: note: expanded from macro '__MATH_TG'
                 float: FUNC ## f ARGS,           \
                        ^
  <scratch space>:73:1: note: expanded from here
  __builtin_fabsf
  ^

Due the use of _Generic from TG_MATH.

Reviewed-by: Sam James <sam@gentoo.org>
2025-10-21 09:24:21 -03:00

89 lines
3.1 KiB
C

/* Check for underflow and force underflow exceptions.
Copyright (C) 2015-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _MATH_UNDERFLOW_H
#define _MATH_UNDERFLOW_H 1
#include <float.h>
#include <math.h>
#include <math-barriers.h>
#include <libc-diag.h>
#define fabs_tg(x) __MATH_TG ((x), (__typeof (x)) __builtin_fabs, (x))
/* These must be function-like macros because some __MATH_TG
implementations macro-expand the function-name argument before
concatenating a suffix to it. */
#define min_of_type_f() FLT_MIN
#define min_of_type_() DBL_MIN
#define min_of_type_l() LDBL_MIN
#define min_of_type_f128() FLT128_MIN
#define min_of_type(x) __MATH_TG ((x), (__typeof (x)) min_of_type_, ())
/* If X (which is not a NaN) is subnormal, force an underflow
exception.
clang issues a warning where _Generic is using a non expected
builtin which may cause truncation of value.
clang warns the value might be truncated due the use of _Generics. */
#define math_check_force_underflow(x) \
do \
{ \
DIAG_PUSH_NEEDS_COMMENT_CLANG; \
DIAG_IGNORE_NEEDS_COMMENT_CLANG (18, "-Wabsolute-value"); \
__typeof (x) force_underflow_tmp = (x); \
if (fabs_tg (force_underflow_tmp) \
< min_of_type (force_underflow_tmp)) \
{ \
__typeof (force_underflow_tmp) force_underflow_tmp2 \
= force_underflow_tmp * force_underflow_tmp; \
math_force_eval (force_underflow_tmp2); \
} \
DIAG_POP_NEEDS_COMMENT_CLANG; \
} \
while (0)
/* Likewise, but X is also known to be nonnegative. */
#define math_check_force_underflow_nonneg(x) \
do \
{ \
__typeof (x) force_underflow_tmp = (x); \
if (force_underflow_tmp \
< min_of_type (force_underflow_tmp)) \
{ \
__typeof (force_underflow_tmp) force_underflow_tmp2 \
= force_underflow_tmp * force_underflow_tmp; \
math_force_eval (force_underflow_tmp2); \
} \
} \
while (0)
/* Likewise, for both real and imaginary parts of a complex
result. */
#define math_check_force_underflow_complex(x) \
do \
{ \
__typeof (x) force_underflow_complex_tmp = (x); \
math_check_force_underflow (__real__ force_underflow_complex_tmp); \
math_check_force_underflow (__imag__ force_underflow_complex_tmp); \
} \
while (0)
#endif /* math-underflow.h */