From: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
Date: Tue, 17 Jun 2014 13:46:25 +0000 (-0500)
Subject: PowerPC: Fix nearbyintl failure for few inputs
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e986751f5c05f3363c01c717972f87a681da0d0;p=thirdparty%2Fglibc.git

PowerPC: Fix nearbyintl failure for few inputs

This patch fixes few failures in nearbyintl() where the fraction part is
close to 0.5.i  The new tests added report few extra failures in
nearbyint_downward and nearbyint_towardzero which is a known issue.

Fixes #17031.

This is a backport of 754c5a08aacb44895d1ab97c553ce424eb43f761.
---

diff --git a/ChangeLog b/ChangeLog
index a8a24b51278..95dcce84ac7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-16-17  Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
+
+	[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.
+
 2014-06-11  Vidya Ranganathan  <vidya@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/powerpc64/power7/strcmp.S: New file: Optimization.
diff --git a/NEWS b/NEWS
index 99bda3c9b89..96b7621c0f2 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,8 @@ Version 2.19.1
 
 * The following bugs are resolved with this release:
 
-  16545, 16683, 16689, 16701, 16706, 16707, 16739, 16815, 16619, 16740.
+  16545, 16683, 16689, 16701, 16706, 16707, 16739, 16815, 16619, 16740,
+  17031.
 
 Version 2.19
 
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 1c5c022f4f6..848b89ee7b8 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -10519,6 +10519,10 @@ static const struct test_f_f_data nearbyint_test_data[] =
     TEST_f_f (nearbyint,  34503599627370498.515625L, 34503599627370499.0L),
     TEST_f_f (nearbyint, -34503599627370498.515625L, -34503599627370499.0L),
 # if LDBL_MANT_DIG >= 106
+    TEST_f_f (nearbyint, 1024.5000000000001L, 1025.0L, NO_INEXACT_EXCEPTION),
+    TEST_f_f (nearbyint, 1025.5000000000001L, 1026.0L, NO_INEXACT_EXCEPTION),
+    TEST_f_f (nearbyint, -1024.5000000000001L, -1025.0L, NO_INEXACT_EXCEPTION),
+    TEST_f_f (nearbyint, -1025.5000000000001L, -1026.0L, NO_INEXACT_EXCEPTION),
     TEST_f_f (nearbyint,  1192568192774434123539907640624.484375L, 1192568192774434123539907640624.0L),
     TEST_f_f (nearbyint, -1192568192774434123539907640624.484375L, -1192568192774434123539907640624.0L),
 # endif
@@ -11335,6 +11339,10 @@ static const struct test_f_f_data rint_test_data[] =
     TEST_f_f (rint, 4503599627370497.5L, 4503599627370498.0L, INEXACT_EXCEPTION),
 
 # if LDBL_MANT_DIG > 100
+    TEST_f_f (rint, 1024.5000000000001L, 1025.0L, INEXACT_EXCEPTION),
+    TEST_f_f (rint, 1025.5000000000001L, 1026.0L, INEXACT_EXCEPTION),
+    TEST_f_f (rint, -1024.5000000000001L, -1025.0L, INEXACT_EXCEPTION),
+    TEST_f_f (rint, -1025.5000000000001L, -1026.0L, INEXACT_EXCEPTION),
     TEST_f_f (rint, 4503599627370494.5000000000001L, 4503599627370495.0L, INEXACT_EXCEPTION),
     TEST_f_f (rint, 4503599627370495.5000000000001L, 4503599627370496.0L, INEXACT_EXCEPTION),
     TEST_f_f (rint, 4503599627370496.5000000000001L, 4503599627370497.0L, INEXACT_EXCEPTION),
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c b/sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c
index 4e997a68f9a..8f34604f54c 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]);