diff --git a/lib/msun/src/s_cospi.c b/lib/msun/src/s_cospi.c
index 860219efd3e..2e2f92733a8 100644
--- a/lib/msun/src/s_cospi.c
+++ b/lib/msun/src/s_cospi.c
@@ -138,7 +138,8 @@ cospi(double x)
 		return (j0 & 1 ? -c : c);
 	}
 
-	if (ix >= 0x7f800000)
+	/* x = +-inf or nan. */
+	if (ix >= 0x7ff00000)
 		return (vzero / vzero);
 
 	/*
diff --git a/lib/msun/src/s_sinpi.c b/lib/msun/src/s_sinpi.c
index 858459a5fcb..bc3759e567a 100644
--- a/lib/msun/src/s_sinpi.c
+++ b/lib/msun/src/s_sinpi.c
@@ -155,7 +155,8 @@ sinpi(double x)
 		return ((hx & 0x80000000) ? -s : s);
 	}
 
-	if (ix >= 0x7f800000)
+	/* x = +-inf or nan. */
+	if (ix >= 0x7ff00000)
 		return (vzero / vzero);
 
 	/*
diff --git a/lib/msun/src/s_tanpi.c b/lib/msun/src/s_tanpi.c
index 01d4c74367f..f911d56156b 100644
--- a/lib/msun/src/s_tanpi.c
+++ b/lib/msun/src/s_tanpi.c
@@ -163,7 +163,7 @@ tanpi(double x)
 	}
 
 	/* x = +-inf or nan. */
-	if (ix >= 0x7f800000)
+	if (ix >= 0x7ff00000)
 		return (vzero / vzero);
 
 	/*