Fix csin, csinh overflow in directed rounding modes (bug 18593).

csin and csinh can produce bad results when overflowing in directed
rounding modes, because a multiplication that can overflow is followed
by a possible negation.  This patch fixes this by negating one of the
arguments of the multiplication before the multiplication instead of
negating the result.

The new tests for this issue are added to auto-libm-test-in, starting
use of that file for csin and csinh.  The issue was found in the
course of moving existing tests for csin and csinh (existing tests, by
being enabled in more cases than previously, showed the issue for
float and double but not for long double); that move will now be done
separately.

Tested for x86_64 and x86 and ulps updated accordingly.

	[BZ #18593]
	* math/s_csin.c (__csin): Negate before rather than after possibly
	overflowing multiplication.
	* math/s_csinf.c (__csinf): Likewise.
	* math/s_csinh.c (__csinh): Likewise.
	* math/s_csinhf.c (__csinhf): Likewise.
	* math/s_csinhl.c (__csinhl): Likewise.
	* math/s_csinl.c (__csinl): Likewise.
	* math/auto-libm-test-in: Add some tests of csin and csinh.
	* math/auto-libm-test-out: Regenerated.
	* math/libm-test.inc (csin_test_data): Use AUTO_TESTS_c_c.
	(csinh_test_data): Likewise.
	* sysdeps/x86_64/fpu/libm-test-ulps: Update.

1 files changed, 3 insertions, 3 deletions

diff --git a/math/s_csin.c b/math/s_csin.c
index f1ddb4e780..ceee25fdda 100644
--- a/math/s_csin.c
+++ b/math/s_csin.c
@@ -52,6 +52,9 @@ __csin (__complex__ double x)
 	      cosix = 1.0;
 	    }
 
+	  if (negate)
+	    sinix = -sinix;
+
 	  if (fabs (__imag__ x) > t)
 	    {
 	      double exp_t = __ieee754_exp (t);
@@ -86,9 +89,6 @@ __csin (__complex__ double x)
 	      __imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
 	    }
 
-	  if (negate)
-	    __real__ retval = -__real__ retval;
-
 	  if (fabs (__real__ retval) < DBL_MIN)
 	    {
 	      volatile double force_underflow