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math: Simplify hypotf implementation 

Use a more optimized comparison for check for NaN and infinite and
add an inlined issignaling implementation for float.  With gcc it
results in 2 FP comparisons.

The file Copyright is also changed to use  GPL, the implementation was
completely changed by 7c10fd3515 to use double precision instead of
scaling and this change removes all the GET_FLOAT_WORD usage.

Checked on x86_64-linux-gnu.
This commit is contained in:
Adhemerval Zanella 2021-04-05 14:49:47 -03:00
parent 5afe4c0d69
commit 7fe0ace3e2
2 changed files with 38 additions and 36 deletions
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65
sysdeps/ieee754/flt-32/e_hypotf.c
View File

@ -1,46 +1,39 @@
/* e_hypotf.c -- float version of e_hypot.c. /* Euclidean distance function. Float/Binary32 version.
*/ Copyright (C) 2012-2021 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
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this The GNU C Library is distributed in the hope that it will be useful,
* software is freely granted, provided that this notice but WITHOUT ANY WARRANTY; without even the implied warranty of
* is preserved. 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/>. */
#include <math.h>
#include <math_private.h>
#include <libm-alias-finite.h> #include <libm-alias-finite.h>
#include <math.h>
#include <math-narrow-eval.h>
#include <math_private.h>
float float
__ieee754_hypotf(float x, float y) __ieee754_hypotf (float x, float y)
{ {
double d_x, d_y; if (!isfinite (x) || !isfinite (y))
int32_t ha, hb; {
if ((isinf (x) || isinf (y))
&& !issignaling (x) && !issignaling (y))
return INFINITY;
return x + y;
}
GET_FLOAT_WORD(ha,x); return math_narrow_eval ((float) sqrt ((double) x * (double) x
ha &= 0x7fffffff; + (double) y * (double) y));
GET_FLOAT_WORD(hb,y);
hb &= 0x7fffffff;
if (ha == 0x7f800000 && !issignaling (y))
return fabsf(x);
else if (hb == 0x7f800000 && !issignaling (x))
return fabsf(y);
else if (ha > 0x7f800000 || hb > 0x7f800000)
return fabsf(x) * fabsf(y);
else if (ha == 0)
return fabsf(y);
else if (hb == 0)
return fabsf(x);
d_x = (double) x;
d_y = (double) y;
return (float) sqrt(d_x * d_x + d_y * d_y);
} }
#ifndef __ieee754_hypotf #ifndef __ieee754_hypotf
libm_alias_finite (__ieee754_hypotf, __hypotf) libm_alias_finite (__ieee754_hypotf, __hypotf)

9
sysdeps/ieee754/flt-32/math_config.h
View File

@ -101,6 +101,15 @@ asdouble (uint64_t i)
return u.f; return u.f;
} }
static inline int
issignalingf_inline (float x)
{
uint32_t ix = asuint (x);
if (HIGH_ORDER_BIT_IS_SET_FOR_SNAN)
return (ix & 0x7fc00000) == 0x7fc00000;
return 2 * (ix ^ 0x00400000) > 2 * 0x7fc00000UL;
}
#define NOINLINE __attribute__ ((noinline)) #define NOINLINE __attribute__ ((noinline))
attribute_hidden float __math_oflowf (uint32_t); attribute_hidden float __math_oflowf (uint32_t);