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Fix exp10 spurious overflows (bug 13924).

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This commit is contained in:
Joseph Myers 2012-04-30 09:37:01 +00:00
parent 6c1ff08cf8
commit 9568c0c225
6 changed files with 43 additions and 18 deletions
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15
ChangeLog
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@ -1,3 +1,18 @@
2012-04-30 Joseph Myers <joseph@codesourcery.com>
[BZ #13884]
[BZ #13924]
* math/e_exp10.c: Include <float.h>.
(__ieee754_exp10): Handle underflow here rather than multiplying
large negative argument by M_LN10.
* math/e_exp10f.c (__ieee754_exp10f): Call __ieee754_exp instead
of __ieee754_expf.
* math/e_exp10l.c: Include <float.h>.
(__ieee754_exp10l): Handle underflow here rather than multiplying
large negative argument by M_LN10l.
* math/libm-test.inc (exp10_test): Add another test. Do not allow
spurious overflow exception on underflow.
2012-04-29 Marek Polacek <polacek@redhat.com>
* misc/sys/cdefs.h (__attribute_artificial__): New macro.

4
NEWS
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@ -21,8 +21,8 @@ Version 2.16
13739, 13758, 13760, 13761, 13786, 13792, 13806, 13824, 13840, 13841,
13844, 13846, 13851, 13852, 13854, 13871, 13872, 13873, 13879, 13883,
13886, 13892, 13895, 13908, 13910, 13911, 13912, 13913, 13915, 13916,
13917, 13918, 13919, 13920, 13921, 13926, 13927, 13928, 13938, 13941,
13963, 13967, 13970, 13973, 14027, 14033
13917, 13918, 13919, 13920, 13921, 13924, 13926, 13927, 13928, 13938,
13941, 13963, 13967, 13970, 13973, 14027, 14033
* ISO C11 support:

13
math/e_exp10.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1998, 2011 Free Software Foundation, Inc.
/* Copyright (C) 1998-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
@ -18,13 +18,16 @@
#include <math.h>
#include <math_private.h>
#include <float.h>
double
__ieee754_exp10 (double arg)
{
/* This is a very stupid and inprecise implementation. It'll get
replaced sometime (soon?). */
return __ieee754_exp (M_LN10 * arg);
if (__finite (arg) && arg < DBL_MIN_10_EXP - DBL_DIG - 10)
return DBL_MIN * DBL_MIN;
else
/* This is a very stupid and inprecise implementation. It'll get
replaced sometime (soon?). */
return __ieee754_exp (M_LN10 * arg);
}
strong_alias (__ieee754_exp10, __exp10_finite)

10
math/e_exp10f.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1998, 2011 Free Software Foundation, Inc.
/* Copyright (C) 1998-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
@ -23,8 +23,10 @@
float
__ieee754_exp10f (float arg)
{
/* This is a very stupid and inprecise implementation. It'll get
replaced sometime (soon?). */
return __ieee754_expf (M_LN10 * arg);
/* The argument to exp needs to be calculated in enough precision
that the fractional part has as much precision as float, in
addition to the bits in the integer part; using double ensures
this. */
return __ieee754_exp (M_LN10 * arg);
}
strong_alias (__ieee754_exp10f, __exp10f_finite)

13
math/e_exp10l.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1998, 2011 Free Software Foundation, Inc.
/* Copyright (C) 1998-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
@ -18,13 +18,16 @@
#include <math.h>
#include <math_private.h>
#include <float.h>
long double
__ieee754_exp10l (long double arg)
{
/* This is a very stupid and inprecise implementation. It'll get
replaced sometime (soon?). */
return __ieee754_expl (M_LN10l * arg);
if (__finitel (arg) && arg < LDBL_MIN_10_EXP - LDBL_DIG - 10)
return LDBL_MIN * LDBL_MIN;
else
/* This is a very stupid and inprecise implementation. It'll get
replaced sometime (soon?). */
return __ieee754_expl (M_LN10l * arg);
}
strong_alias (__ieee754_exp10l, __exp10l_finite)

6
math/libm-test.inc
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@ -3196,12 +3196,14 @@ exp10_test (void)
TEST_f_f (exp10, nan_value, nan_value);
TEST_f_f (exp10, 3, 1000);
TEST_f_f (exp10, -1, 0.1L);
#ifdef TEST_FLOAT /* Bug 13884: inaccurate results except for float. */
TEST_f_f (exp10, 36, 1.0e36L);
#endif
TEST_f_f (exp10, 1e6, plus_infty, OVERFLOW_EXCEPTION);
TEST_f_f (exp10, -1e6, 0);
#ifndef TEST_LDOUBLE /* Bug 13914: spurious exceptions. */
TEST_f_f (exp10, max_value, plus_infty, OVERFLOW_EXCEPTION);
/* Bug 13924: spurious OVERFLOW exception may be present. */
TEST_f_f (exp10, -max_value, 0, OVERFLOW_EXCEPTION_OK);
TEST_f_f (exp10, -max_value, 0);
#endif
TEST_f_f (exp10, 0.75L, 5.62341325190349080394951039776481231L);