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347a5b592c
Converting double precision constants to float is now affected by the runtime dynamic rounding mode instead of being evaluated at compile time with default rounding mode (except static object initializers). This can change the computed result and cause performance regression. The known correctness issues (increased ulp errors) are already fixed, this patch fixes remaining cases of unnecessary runtime conversions. Add float M_* macros to math.h as new GNU extension API. To avoid conversions the new M_* macros are used and instead of casting double literals to float, use float literals (only required if the conversion is inexact). The patch was tested on aarch64 where the following symbols had new spurious conversion instructions that got fixed: __clog10f __gammaf_r_finite@GLIBC_2.17 __j0f_finite@GLIBC_2.17 __j1f_finite@GLIBC_2.17 __jnf_finite@GLIBC_2.17 __kernel_casinhf __lgamma_negf __log1pf __y0f_finite@GLIBC_2.17 __y1f_finite@GLIBC_2.17 cacosf cacoshf casinhf catanf catanhf clogf gammaf_positive Fixes bug 28713. Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
/* Return arc tangent of complex float type.
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Copyright (C) 1997-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <complex.h>
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#include <math.h>
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#include <math_private.h>
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#include <math-underflow.h>
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#include <float.h>
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CFLOAT
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M_DECL_FUNC (__catan) (CFLOAT x)
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{
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CFLOAT res;
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int rcls = fpclassify (__real__ x);
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int icls = fpclassify (__imag__ x);
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if (__glibc_unlikely (rcls <= FP_INFINITE || icls <= FP_INFINITE))
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{
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if (rcls == FP_INFINITE)
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{
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__real__ res = M_COPYSIGN (M_MLIT (M_PI_2), __real__ x);
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__imag__ res = M_COPYSIGN (0, __imag__ x);
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}
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else if (icls == FP_INFINITE)
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{
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if (rcls >= FP_ZERO)
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__real__ res = M_COPYSIGN (M_MLIT (M_PI_2), __real__ x);
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else
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__real__ res = M_NAN;
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__imag__ res = M_COPYSIGN (0, __imag__ x);
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}
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else if (icls == FP_ZERO || icls == FP_INFINITE)
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{
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__real__ res = M_NAN;
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__imag__ res = M_COPYSIGN (0, __imag__ x);
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}
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else
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{
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__real__ res = M_NAN;
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__imag__ res = M_NAN;
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}
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}
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else if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
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{
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res = x;
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}
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else
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{
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if (M_FABS (__real__ x) >= 16 / M_EPSILON
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|| M_FABS (__imag__ x) >= 16 / M_EPSILON)
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{
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__real__ res = M_COPYSIGN (M_MLIT (M_PI_2), __real__ x);
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if (M_FABS (__real__ x) <= 1)
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__imag__ res = 1 / __imag__ x;
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else if (M_FABS (__imag__ x) <= 1)
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__imag__ res = __imag__ x / __real__ x / __real__ x;
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else
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{
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FLOAT h = M_HYPOT (__real__ x / 2, __imag__ x / 2);
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__imag__ res = __imag__ x / h / h / 4;
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}
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}
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else
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{
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FLOAT den, absx, absy;
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absx = M_FABS (__real__ x);
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absy = M_FABS (__imag__ x);
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if (absx < absy)
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{
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FLOAT t = absx;
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absx = absy;
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absy = t;
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}
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if (absy < M_EPSILON / 2)
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{
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den = (1 - absx) * (1 + absx);
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if (den == 0)
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den = 0;
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}
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else if (absx >= 1)
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den = (1 - absx) * (1 + absx) - absy * absy;
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else if (absx >= M_LIT (0.75) || absy >= M_LIT (0.5))
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den = -M_SUF (__x2y2m1) (absx, absy);
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else
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den = (1 - absx) * (1 + absx) - absy * absy;
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__real__ res = M_LIT (0.5) * M_ATAN2 (2 * __real__ x, den);
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if (M_FABS (__imag__ x) == 1
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&& M_FABS (__real__ x) < M_EPSILON * M_EPSILON)
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__imag__ res = (M_COPYSIGN (M_LIT (0.5), __imag__ x)
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* (M_MLIT (M_LN2)
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- M_LOG (M_FABS (__real__ x))));
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else
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{
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FLOAT r2 = 0, num, f;
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if (M_FABS (__real__ x) >= M_EPSILON * M_EPSILON)
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r2 = __real__ x * __real__ x;
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num = __imag__ x + 1;
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num = r2 + num * num;
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den = __imag__ x - 1;
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den = r2 + den * den;
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f = num / den;
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if (f < M_LIT (0.5))
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__imag__ res = M_LIT (0.25) * M_LOG (f);
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else
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{
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num = 4 * __imag__ x;
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__imag__ res = M_LIT (0.25) * M_LOG1P (num / den);
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}
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}
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}
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math_check_force_underflow_complex (res);
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}
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return res;
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}
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declare_mgen_alias (__catan, catan)
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