math: fix logb(-0.0) in downward rounding mode

[musl] / src / math / sinh.c

diff --git a/src/math/sinh.c b/src/math/sinh.c
index 47e36bf..00022c4 100644 (file)
--- a/src/math/sinh.c
+++ b/src/math/sinh.c
@@ -23,8 +23,8 @@ double sinh(double x)
                t = expm1(absx);
                if (w < 0x3ff00000) {
                        if (w < 0x3ff00000 - (26<<20))
-                               /* note: inexact is raised by expm1 */
-                               /* note: this branch avoids underflow */
+                               /* note: inexact and underflow are raised by expm1 */
+                               /* note: this branch avoids spurious underflow */
                                return x;
                        return h*(2*t - t*t/(t+1));
                }