diff --git a/src/math/all_test.go b/src/math/all_test.go
index 84061be264..6286584e0c 100644
--- a/src/math/all_test.go
+++ b/src/math/all_test.go
@@ -946,16 +946,20 @@ var expSC = []float64{
 
 var vfexpm1SC = []float64{
 	Inf(-1),
+	-710,
 	Copysign(0, -1),
 	0,
+	710,
 	Inf(1),
 	NaN(),
 }
 var expm1SC = []float64{
+	-1,
 	-1,
 	Copysign(0, -1),
 	0,
 	Inf(1),
+	Inf(1),
 	NaN(),
 }
 
diff --git a/src/math/expm1.go b/src/math/expm1.go
index 8f56e15cc4..064e131161 100644
--- a/src/math/expm1.go
+++ b/src/math/expm1.go
@@ -158,11 +158,11 @@ func expm1(x float64) float64 {
 
 	// filter out huge argument
 	if absx >= Ln2X56 { // if |x| >= 56 * ln2
-		if absx >= Othreshold { // if |x| >= 709.78...
-			return Inf(1) // overflow
-		}
 		if sign {
-			return -1 // x < -56*ln2, return -1.0
+			return -1 // x < -56*ln2, return -1
+		}
+		if absx >= Othreshold { // if |x| >= 709.78...
+			return Inf(1)
 		}
 	}