svn commit: r226600 - head/lib/msun/src

[David Schultz]

Author: das
Date: Fri Oct 21 06:30:16 2011
New Revision: 226600
URL: http://svn.freebsd.org/changeset/base/226600

Log:
  Fix a corner case: tan(large + Inf i) == NaN + NaN i.

Modified:
  head/lib/msun/src/s_ctanh.c
  head/lib/msun/src/s_ctanhf.c

Modified: head/lib/msun/src/s_ctanh.c
==============================================================================
--- head/lib/msun/src/s_ctanh.c	Fri Oct 21 06:29:32 2011	(r226599)
+++ head/lib/msun/src/s_ctanh.c	Fri Oct 21 06:30:16 2011	(r226600)
@@ -108,6 +108,13 @@ ctanh(double complex z)
 	}
 
 	/*
+	 * ctanh(x + i NAN) = NaN + i NaN
+	 * ctanh(x +- i Inf) = NaN + i NaN
+	 */
+	if (!isfinite(y))
+		return (cpack(y - y, y - y));
+
+	/*
 	 * ctanh(+-huge + i +-y) ~= +-1 +- i 2sin(2y)/exp(2x), using the
 	 * approximation sinh^2(huge) ~= exp(2*huge) / 4.
 	 * We use a modified formula to avoid spurious overflow.

Modified: head/lib/msun/src/s_ctanhf.c
==============================================================================
--- head/lib/msun/src/s_ctanhf.c	Fri Oct 21 06:29:32 2011	(r226599)
+++ head/lib/msun/src/s_ctanhf.c	Fri Oct 21 06:30:16 2011	(r226600)
@@ -57,6 +57,9 @@ ctanhf(float complex z)
 		    copysignf(0, isinf(y) ? y : sinf(y) * cosf(y))));
 	}
 
+	if (!isfinite(y))
+		return (cpackf(y - y, y - y));
+
 	if (ix >= 0x41300000) {	/* x >= 11 */
 		float exp_mx = expf(-fabsf(x));
 		return (cpackf(copysignf(1, x),