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[PATCH] [BZ #17031][PowerPC64] Fix nearbyintl failure for few inputs
- From: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Cc: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- Date: Wed, 11 Jun 2014 06:12:15 -0500
- Subject: [PATCH] [BZ #17031][PowerPC64] Fix nearbyintl failure for few inputs
- Authentication-results: sourceware.org; auth=none
- References: <1402390928-37048-1-git-send-email-raji at linux dot vnet dot ibm dot com>
This patch fixes few failures in nearbyintl() where the fraction part is close
to 0.5.The new tests added report few extra failures in nearbyint_downward and
nearbyint_towardzero which is a known issue.
[BZ #17031]
* sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c: Consider the low
double, adjusted for any remainder from the high double.
* math/libm-test.inc (nearbyint): Add tests.
(rint): Likewise.
Signed-off-by: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
---
NEWS | 2 +-
math/libm-test.inc | 8 ++++++++
sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c | 5 +++++
3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/NEWS b/NEWS
index ca3ef63..066a2c8 100644
--- a/NEWS
+++ b/NEWS
@@ -19,7 +19,7 @@ Version 2.20
16791, 16796, 16799, 16800, 16815, 16823, 16824, 16831, 16838, 16849,
16854, 16876, 16877, 16878, 16882, 16885, 16888, 16890, 16912, 16915,
16916, 16917, 16922, 16927, 16928, 16932, 16943, 16958, 16965, 16966,
- 16967, 16977, 16978, 16984, 16990, 17009, 17042.
+ 16967, 16977, 16978, 16984, 16990, 17009, 17031, 17042.
* The minimum Linux kernel version that this version of the GNU C Library
can be used with is 2.6.32.
diff --git a/math/libm-test.inc b/math/libm-test.inc
index fa8e238..d98d85c 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -8188,6 +8188,10 @@ static const struct test_f_f_data nearbyint_test_data[] =
TEST_f_f (nearbyint, 4503599627370496.75L, 4503599627370496.0L, NO_INEXACT_EXCEPTION, 4503599627370497.0L, NO_INEXACT_EXCEPTION, 4503599627370496.0L, NO_INEXACT_EXCEPTION, 4503599627370497.0L, NO_INEXACT_EXCEPTION),
TEST_f_f (nearbyint, 4503599627370497.5L, 4503599627370497.0L, NO_INEXACT_EXCEPTION, 4503599627370498.0L, NO_INEXACT_EXCEPTION, 4503599627370497.0L, NO_INEXACT_EXCEPTION, 4503599627370498.0L, NO_INEXACT_EXCEPTION),
# if LDBL_MANT_DIG > 100
+ TEST_f_f (nearbyint, 1024.5000000000001L, 1024.0L, NO_INEXACT_EXCEPTION, 1025.0L, NO_INEXACT_EXCEPTION, 1024.0L, NO_INEXACT_EXCEPTION, 1025.0L, NO_INEXACT_EXCEPTION),
+ TEST_f_f (nearbyint, 1025.5000000000001L, 1025.0L, NO_INEXACT_EXCEPTION, 1026.0L, NO_INEXACT_EXCEPTION, 1025.0L, NO_INEXACT_EXCEPTION, 1026.0L, NO_INEXACT_EXCEPTION),
+ TEST_f_f (nearbyint, -1024.5000000000001L, -1025.0L, NO_INEXACT_EXCEPTION, -1025.0L, NO_INEXACT_EXCEPTION, -1024.0L, NO_INEXACT_EXCEPTION, -1024.0L, NO_INEXACT_EXCEPTION),
+ TEST_f_f (nearbyint, -1025.5000000000001L, -1026.0L, NO_INEXACT_EXCEPTION, -1026.0L, NO_INEXACT_EXCEPTION, -1025.0L, NO_INEXACT_EXCEPTION, -1025.0L, NO_INEXACT_EXCEPTION),
TEST_f_f (nearbyint, 4503599627370494.5000000000001L, 4503599627370494.0L, NO_INEXACT_EXCEPTION, 4503599627370495.0L, NO_INEXACT_EXCEPTION, 4503599627370494.0L, NO_INEXACT_EXCEPTION, 4503599627370495.0L, NO_INEXACT_EXCEPTION),
TEST_f_f (nearbyint, 4503599627370495.5000000000001L, 4503599627370495.0L, NO_INEXACT_EXCEPTION, 4503599627370496.0L, NO_INEXACT_EXCEPTION, 4503599627370495.0L, NO_INEXACT_EXCEPTION, 4503599627370496.0L, NO_INEXACT_EXCEPTION),
TEST_f_f (nearbyint, 4503599627370496.5000000000001L, 4503599627370496.0L, NO_INEXACT_EXCEPTION, 4503599627370497.0L, NO_INEXACT_EXCEPTION, 4503599627370496.0L, NO_INEXACT_EXCEPTION, 4503599627370497.0L, NO_INEXACT_EXCEPTION),
@@ -8890,6 +8894,10 @@ static const struct test_f_f_data rint_test_data[] =
TEST_f_f (rint, 4503599627370496.75L, 4503599627370496.0L, INEXACT_EXCEPTION, 4503599627370497.0L, INEXACT_EXCEPTION, 4503599627370496.0L, INEXACT_EXCEPTION, 4503599627370497.0L, INEXACT_EXCEPTION),
TEST_f_f (rint, 4503599627370497.5L, 4503599627370497.0L, INEXACT_EXCEPTION, 4503599627370498.0L, INEXACT_EXCEPTION, 4503599627370497.0L, INEXACT_EXCEPTION, 4503599627370498.0L, INEXACT_EXCEPTION),
# if LDBL_MANT_DIG > 100
+ TEST_f_f (rint, 1024.5000000000001L, 1024.0L, INEXACT_EXCEPTION, 1025.0L, INEXACT_EXCEPTION, 1024.0L, INEXACT_EXCEPTION, 1025.0L, INEXACT_EXCEPTION),
+ TEST_f_f (rint, 1025.5000000000001L, 1025.0L, INEXACT_EXCEPTION, 1026.0L, INEXACT_EXCEPTION, 1025.0L, INEXACT_EXCEPTION, 1026.0L, INEXACT_EXCEPTION),
+ TEST_f_f (rint, -1024.5000000000001L, -1025.0L, INEXACT_EXCEPTION, -1025.0L, INEXACT_EXCEPTION, -1024.0L, INEXACT_EXCEPTION, -1024.0L, INEXACT_EXCEPTION),
+ TEST_f_f (rint, -1025.5000000000001L, -1026.0L, INEXACT_EXCEPTION, -1026.0L, INEXACT_EXCEPTION, -1025.0L, INEXACT_EXCEPTION, -1025.0L, INEXACT_EXCEPTION),
TEST_f_f (rint, 4503599627370494.5000000000001L, 4503599627370494.0L, INEXACT_EXCEPTION, 4503599627370495.0L, INEXACT_EXCEPTION, 4503599627370494.0L, INEXACT_EXCEPTION, 4503599627370495.0L, INEXACT_EXCEPTION),
TEST_f_f (rint, 4503599627370495.5000000000001L, 4503599627370495.0L, INEXACT_EXCEPTION, 4503599627370496.0L, INEXACT_EXCEPTION, 4503599627370495.0L, INEXACT_EXCEPTION, 4503599627370496.0L, INEXACT_EXCEPTION),
TEST_f_f (rint, 4503599627370496.5000000000001L, 4503599627370496.0L, INEXACT_EXCEPTION, 4503599627370497.0L, INEXACT_EXCEPTION, 4503599627370496.0L, INEXACT_EXCEPTION, 4503599627370497.0L, INEXACT_EXCEPTION),
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c b/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c
index 4e997a6..8f34604 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c
@@ -38,6 +38,7 @@ __nearbyintl (long double x)
if (fabs (u.d[0].d) < TWO52)
{
+ double xh = u.d[0].d;
double high = u.d[0].d;
feholdexcept (&env);
if (high > 0.0)
@@ -52,6 +53,10 @@ __nearbyintl (long double x)
high += TWO52;
if (high == 0.0) high = -0.0;
}
+ if (u.d[1].d > 0.0 && (xh - high == 0.5))
+ high += 1.0;
+ else if (u.d[1].d < 0.0 && (-(xh - high) == 0.5))
+ high -= 1.0;
u.d[0].d = high;
u.d[1].d = 0.0;
math_force_eval (u.d[0]);
--
1.8.4.2