From: Joseph Myers <joseph@codesourcery.com>
Date: Mon, 6 Jun 2016 22:10:11 +0000 (+0000)
Subject: Fix dbl-64 acos (sNaN) (bug 20212).
X-Git-Tag: glibc-2.24~159
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=af0cfbaf1df1549ca0bc70bd6b4bc54004d11680;p=glibc.git

Fix dbl-64 acos (sNaN) (bug 20212).

The dbl-64 version of acos returns sNaN for sNaN arguments.  This
patch fixes it to add NaN arguments to themselves so that qNaN is
returned in this case.

Tested for x86_64 and x86.

	[BZ #20212]
	* sysdeps/ieee754/dbl-64/e_asin.c (__ieee754_acos): Add NaN
	argument to itself.
	* math/libm-test.inc (acos_test_data): Add sNaN tests.
---

diff --git a/ChangeLog b/ChangeLog
index 6c1c36a090..9930b5e5c2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-06-06  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #20212]
+	* sysdeps/ieee754/dbl-64/e_asin.c (__ieee754_acos): Add NaN
+	argument to itself.
+	* math/libm-test.inc (acos_test_data): Add sNaN tests.
+
 2016-06-06  Tulio Magno Quites Machado Filho  <tuliom@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/powerpc64/power8/strcasestr.S (__strcasestr):
diff --git a/math/libm-test.inc b/math/libm-test.inc
index aaa01488ec..698172080c 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -1799,6 +1799,8 @@ static const struct test_f_f_data acos_test_data[] =
     TEST_f_f (acos, minus_infty, qnan_value, INVALID_EXCEPTION|ERRNO_EDOM),
     TEST_f_f (acos, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_f_f (acos, -qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_f (acos, snan_value, qnan_value, INVALID_EXCEPTION),
+    TEST_f_f (acos, -snan_value, qnan_value, INVALID_EXCEPTION),
 
     /* |x| > 1: */
     TEST_f_f (acos, 1.125L, qnan_value, INVALID_EXCEPTION|ERRNO_EDOM),
diff --git a/sysdeps/ieee754/dbl-64/e_asin.c b/sysdeps/ieee754/dbl-64/e_asin.c
index d8c012d1d3..5d5fb01132 100644
--- a/sysdeps/ieee754/dbl-64/e_asin.c
+++ b/sysdeps/ieee754/dbl-64/e_asin.c
@@ -633,7 +633,7 @@ __ieee754_acos(double x)
   else
   if (k==0x3ff00000 && u.i[LOW_HALF]==0) return (m>0)?0:2.0*hp0.x;
   else
-  if (k>0x7ff00000 || (k == 0x7ff00000 && u.i[LOW_HALF] != 0)) return x;
+  if (k>0x7ff00000 || (k == 0x7ff00000 && u.i[LOW_HALF] != 0)) return x + x;
   else {
     u.i[HIGH_HALF]=0x7ff00000;
     v.i[HIGH_HALF]=0x7ff00000;