mirror/glibc
2
0
Fork 0
mirror of git://sourceware.org/git/glibc.git synced 2025-03-31 14:01:18 +08:00
Code Issues Packages Projects Releases Wiki Activity

Fix sign of exact zero return from fma (bug 14638).

Browse Source
This commit is contained in:
Joseph Myers 2012-09-29 18:31:54 +00:00
parent b1fa802e1a
commit 8ec5b01346
9 changed files with 227 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
ChangeLog
View File

@ -1,3 +1,21 @@
2012-09-29 Joseph Myers <joseph@codesourcery.com>
[BZ #14638]
* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Use x * y + z for exact
0 + 0.
* sysdeps/ieee754/dbl-64/s_fmaf.c (__fmaf): Use original rounding
mode for addition resulting in exact zero.
* sysdeps/ieee754/ldbl-128/s_fma.c (__fma): Likewise.
* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Use x * y + z for
exact 0 + 0.
* sysdeps/ieee754/ldbl-96/s_fma.c (__fma): Likewise.
* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.
* math/libm-test.inc (fma_test): Add more tests.
(fma_test_towardzero): New function.
(fma_test_downward): Likewise.
(fma_test_upward): Likewise.
(main): Call the new functions.
2012-09-28 David S. Miller <davem@davemloft.net>
* sysdeps/sparc/fpu/libm-test-ulps: Fix garbage in file.

2
NEWS
View File

@ -15,7 +15,7 @@ Version 2.17
14195, 14237, 14252, 14283, 14298, 14303, 14307, 14328, 14331, 14336,
14337, 14347, 14349, 14376, 14459, 14476, 14505, 14510, 14516, 14518,
14519, 14530, 14532, 14538, 14543, 14544, 14545, 14562, 14576, 14579,
14583, 14587, 14621.
14583, 14587, 14621, 14638.
* Support for STT_GNU_IFUNC symbols added for s390 and s390x.
Optimized versions of memcpy, memset, and memcmp added for System z10 and

174
math/libm-test.inc
View File

@ -4546,6 +4546,36 @@ fma_test (void)
TEST_fff_f (fma, minus_infty, minus_infty, plus_infty, plus_infty);
TEST_fff_f (fma, plus_infty, minus_infty, minus_infty, minus_infty);
TEST_fff_f (fma, plus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, 1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, -1.0, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, 1.0, -1.0, plus_zero);
TEST_fff_f (fma, 1.0, -1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, 1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, -1.0, -1.0, plus_zero);
#if defined (TEST_FLOAT) && FLT_MANT_DIG == 24
TEST_fff_f (fma, 0x1.7ff8p+13, 0x1.000002p+0, 0x1.ffffp-24, 0x1.7ff802p+13);
TEST_fff_f (fma, 0x1.fffp+0, 0x1.00001p+0, -0x1.fffp+0, 0x1.fffp-20);
@ -4607,6 +4637,147 @@ fma_test (void)
}
static void
fma_test_towardzero (void)
{
int save_round_mode;
START (fma_towardzero);
save_round_mode = fegetround ();
if (!fesetround (FE_TOWARDZERO))
{
TEST_fff_f (fma, plus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, 1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, -1.0, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, 1.0, -1.0, plus_zero);
TEST_fff_f (fma, 1.0, -1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, 1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, -1.0, -1.0, plus_zero);
}
fesetround (save_round_mode);
END (fma_towardzero);
}
static void
fma_test_downward (void)
{
int save_round_mode;
START (fma_downward);
save_round_mode = fegetround ();
if (!fesetround (FE_DOWNWARD))
{
TEST_fff_f (fma, plus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, plus_zero, minus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, plus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, 1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, 1.0, minus_zero, plus_zero, minus_zero);
TEST_fff_f (fma, 1.0, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, plus_zero, plus_zero, minus_zero);
TEST_fff_f (fma, -1.0, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, plus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, minus_zero, minus_zero);
TEST_fff_f (fma, plus_zero, -1.0, plus_zero, minus_zero);
TEST_fff_f (fma, plus_zero, -1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, 1.0, plus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, 1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, -1.0, minus_zero, minus_zero);
TEST_fff_f (fma, 1.0, 1.0, -1.0, minus_zero);
TEST_fff_f (fma, 1.0, -1.0, 1.0, minus_zero);
TEST_fff_f (fma, -1.0, 1.0, 1.0, minus_zero);
TEST_fff_f (fma, -1.0, -1.0, -1.0, minus_zero);
}
fesetround (save_round_mode);
END (fma_downward);
}
static void
fma_test_upward (void)
{
int save_round_mode;
START (fma_upward);
save_round_mode = fegetround ();
if (!fesetround (FE_UPWARD))
{
TEST_fff_f (fma, plus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, plus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, 1.0, minus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, plus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, plus_zero, minus_zero, minus_zero);
TEST_fff_f (fma, -1.0, minus_zero, plus_zero, plus_zero);
TEST_fff_f (fma, -1.0, minus_zero, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, 1.0, minus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, plus_zero, -1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, 1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, 1.0, minus_zero, minus_zero);
TEST_fff_f (fma, minus_zero, -1.0, plus_zero, plus_zero);
TEST_fff_f (fma, minus_zero, -1.0, minus_zero, plus_zero);
TEST_fff_f (fma, 1.0, 1.0, -1.0, plus_zero);
TEST_fff_f (fma, 1.0, -1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, 1.0, 1.0, plus_zero);
TEST_fff_f (fma, -1.0, -1.0, -1.0, plus_zero);
}
fesetround (save_round_mode);
END (fma_upward);
}
static void
fmax_test (void)
{
@ -9539,6 +9710,9 @@ main (int argc, char **argv)
/* Multiply and add: */
fma_test ();
fma_test_towardzero ();
fma_test_downward ();
fma_test_upward ();
/* Complex functions: */
cabs_test ();

5
sysdeps/ieee754/dbl-64/s_fma.c
View File

@ -128,6 +128,11 @@ __fma (double x, double y, double z)
y = v.d;
z = w.d;
}
/* Ensure correct sign of exact 0 + 0. */
if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
return x * y + z;
/* Multiplication m1 + m2 = x * y using Dekker's algorithm. */
#define C ((1 << (DBL_MANT_DIG + 1) / 2) + 1)
double x1 = x * C;

7
sysdeps/ieee754/dbl-64/s_fmaf.c
View File

@ -32,8 +32,15 @@ float
__fmaf (float x, float y, float z)
{
fenv_t env;
/* Multiplication is always exact. */
double temp = (double) x * (double) y;
/* Ensure correct sign of an exact zero result by performing the
addition in the original rounding mode in that case. */
if (temp == -z)
return (float) temp + z;
union ieee754_double u;
libc_feholdexcept_setround (&env, FE_TOWARDZERO);

8
sysdeps/ieee754/ldbl-128/s_fma.c
View File

@ -1,5 +1,5 @@
/* Compute x * y + z as ternary operation.
Copyright (C) 2010 Free Software Foundation, Inc.
Copyright (C) 2010-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2010.
@ -33,6 +33,12 @@ __fma (double x, double y, double z)
fenv_t env;
/* Multiplication is always exact. */
long double temp = (long double) x * (long double) y;
/* Ensure correct sign of an exact zero result by performing the
addition in the original rounding mode in that case. */
if (temp == -z)
return (double) temp + z;
union ieee854_long_double u;
feholdexcept (&env);
fesetround (FE_TOWARDZERO);

5
sysdeps/ieee754/ldbl-128/s_fmal.c
View File

@ -129,6 +129,11 @@ __fmal (long double x, long double y, long double z)
y = v.d;
z = w.d;
}
/* Ensure correct sign of exact 0 + 0. */
if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
return x * y + z;
/* Multiplication m1 + m2 = x * y using Dekker's algorithm. */
#define C ((1LL << (LDBL_MANT_DIG + 1) / 2) + 1)
long double x1 = x * C;

6
sysdeps/ieee754/ldbl-96/s_fma.c
View File

@ -1,5 +1,5 @@
/* Compute x * y + z as ternary operation.
Copyright (C) 2010 Free Software Foundation, Inc.
Copyright (C) 2010-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2010.
@ -38,6 +38,10 @@ __fma (double x, double y, double z)
return (x * y) + z;
}
/* Ensure correct sign of exact 0 + 0. */
if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
return x * y + z;
/* Multiplication m1 + m2 = x * y using Dekker's algorithm. */
#define C ((1ULL << (LDBL_MANT_DIG + 1) / 2) + 1)
long double x1 = (long double) x * C;

5
sysdeps/ieee754/ldbl-96/s_fmal.c
View File

@ -129,6 +129,11 @@ __fmal (long double x, long double y, long double z)
y = v.d;
z = w.d;
}
/* Ensure correct sign of exact 0 + 0. */
if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
return x * y + z;
/* Multiplication m1 + m2 = x * y using Dekker's algorithm. */
#define C ((1LL << (LDBL_MANT_DIG + 1) / 2) + 1)
long double x1 = x * C;