Issue #9186: log1p(-1.0) should raise ValueError, not OverflowError.
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 7911251..b1d7a36 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -896,7 +896,7 @@
"gamma(x)\n\nGamma function at x.")
FUNC1A(lgamma, m_lgamma,
"lgamma(x)\n\nNatural logarithm of absolute value of Gamma function at x.")
-FUNC1(log1p, m_log1p, 1,
+FUNC1(log1p, m_log1p, 0,
"log1p(x)\n\nReturn the natural logarithm of 1+x (base e).\n"
"The result is computed in a way which is accurate for x near zero.")
FUNC1(sin, sin, 0,