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Fix dbl-64 asin (sNaN) (bug 20213) [committed]

The dbl-64 version of asin 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.  Committed.

2016-06-06  Joseph Myers  <>

	[BZ #20213]
	* sysdeps/ieee754/dbl-64/e_asin.c (__ieee754_asin): Add NaN
	argument to itself.
	* math/ (asin_test_data): Add sNaN tests.

diff --git a/math/ b/math/
index 6981720..f9b2c8a 100644
--- a/math/
+++ b/math/
@@ -1853,6 +1853,8 @@ static const struct test_f_f_data asin_test_data[] =
     TEST_f_f (asin, minus_infty, qnan_value, INVALID_EXCEPTION|ERRNO_EDOM),
     TEST_f_f (asin, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_f_f (asin, -qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_f (asin, snan_value, qnan_value, INVALID_EXCEPTION),
+    TEST_f_f (asin, -snan_value, qnan_value, INVALID_EXCEPTION),
     /* asin x == qNaN plus invalid exception for |x| > 1.  */
     TEST_f_f (asin, 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 5d5fb01..23e9e7e 100644
--- a/sysdeps/ieee754/dbl-64/e_asin.c
+++ b/sysdeps/ieee754/dbl-64/e_asin.c
@@ -323,7 +323,7 @@ __ieee754_asin(double x){
   /*---------------------------- |x|>=1 -------------------------------*/
   else if (k==0x3ff00000 && u.i[LOW_HALF]==0) return (m>0)?hp0.x:-hp0.x;
-  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 {

Joseph S. Myers

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