diff --git a/lib/msun/ld80/s_expl.c b/lib/msun/ld80/s_expl.c
index dfd49e5f7cdb..2395abe92d93 100644
--- a/lib/msun/ld80/s_expl.c
+++ b/lib/msun/ld80/s_expl.c
@@ -60,9 +60,9 @@ static volatile const long double tiny = 0x1p-10000L;
 
 static const union IEEEl2bits
 /* log(2**16384 - 0.5) rounded towards zero: */
-o_threshold = LD80C(0xb17217f7d1cf79ab, 13, 0,  11356.5234062941439488L),
+o_threshold = LD80C(0xb17217f7d1cf79ab, 13,  11356.5234062941439488L),
 /* log(2**(-16381-64-1)) rounded towards zero: */
-u_threshold = LD80C(0xb21dfe7f09e2baa9, 13, 1, -11399.4985314888605581L);
+u_threshold = LD80C(0xb21dfe7f09e2baa9, 13, -11399.4985314888605581L);
 
 static const double __aligned(64)
 /*
diff --git a/lib/msun/src/math_private.h b/lib/msun/src/math_private.h
index fada0a79fc75..5662df01aaae 100644
--- a/lib/msun/src/math_private.h
+++ b/lib/msun/src/math_private.h
@@ -207,12 +207,16 @@ do {								\
   (d) = se_u.e;							\
 } while (0)
 
-/* Long double constants are broken on i386.  This workaround is OK always. */
-#define	LD80C(m, ex, s, v) {					\
-	/* .e = v, */		/* overwritten */		\
-	.xbits.man = __CONCAT(m, ULL),				\
-	.xbits.expsign = (0x3fff + (ex)) | ((s) ? 0x8000 : 0),	\
+#ifdef __i386__
+/* Long double constants are broken on i386. */
+#define	LD80C(m, ex, v) {						\
+	.xbits.man = __CONCAT(m, ULL),					\
+	.xbits.expsign = (0x3fff + (ex)) | ((v) < 0 ? 0x8000 : 0),	\
 }
+#else
+/* The above works on non-i386 too, but we use this to check v. */
+#define	LD80C(m, ex, v)	{ .e = (v), }
+#endif
 
 #ifdef FLT_EVAL_METHOD
 /*