diff --git a/meson.build b/meson.build
index 36cfcd77..dfb23213 100644
--- a/meson.build
+++ b/meson.build
@@ -164,8 +164,6 @@ endif
 
 math_exts = [
   'sincosf',
-  'isinff',
-  'isnanf',
 ]
 
 foreach mfunc: math_exts
diff --git a/src/graphene-box.c b/src/graphene-box.c
index 2099c60f..a9b3fbb8 100644
--- a/src/graphene-box.c
+++ b/src/graphene-box.c
@@ -427,14 +427,18 @@ graphene_box_get_depth (const graphene_box_t *box)
 static inline bool
 graphene_box_is_empty (const graphene_box_t *box)
 {
-#ifdef HAVE_ISINFF
+#if defined(isinf) && defined(signbit)
   float vmin[3], vmax[3];
 
   graphene_simd4f_dup_3f (box->min.value, vmin);
   graphene_simd4f_dup_3f (box->max.value, vmax);
 
-  return (isinff (vmin[0]) == 1 && isinff (vmin[1]) == 1 && isinff (vmin[2]) == 1) &&
-         (isinff (vmax[0]) == -1 && isinff (vmax[1]) == -1 && isinff (vmax[2]) == -1);
+  return ((isinf (vmin[0]) && !signbit (vmin[0])) &&
+          (isinf (vmin[1]) && !signbit (vmin[1])) &&
+          (isinf (vmin[2]) && !signbit (vmin[2]))) &&
+         ((isinf (vmax[0]) && signbit (vmax[0])) &&
+          (isinf (vmax[1]) && signbit (vmax[1])) &&
+          (isinf (vmax[2]) && signbit (vmax[2])));
 #else
   graphene_simd4f_t neg_inf = graphene_simd4f_init (-INFINITY, -INFINITY, -INFINITY, 0.f);
   graphene_simd4f_t pos_inf = graphene_simd4f_init (INFINITY, INFINITY, INFINITY, 0.f);
@@ -454,14 +458,18 @@ graphene_box_is_empty (const graphene_box_t *box)
 static inline bool
 graphene_box_is_infinity (const graphene_box_t *box)
 {
-#ifdef HAVE_ISINFF
+#if defined(isinf) && defined(signbit)
   float vmin[3], vmax[3];
 
   graphene_simd4f_dup_3f (box->min.value, vmin);
   graphene_simd4f_dup_3f (box->max.value, vmax);
 
-  return (isinff (vmin[0]) == -1 && isinff (vmin[1]) == -1 && isinff (vmin[2]) == -1) &&
-         (isinff (vmax[0]) == 1 && isinff (vmax[1]) == 1 && isinff (vmax[2]) == 1);
+  return ((isinf (vmin[0]) && signbit (vmin[0])) &&
+          (isinf (vmin[1]) && signbit (vmin[1])) &&
+          (isinf (vmin[2]) && signbit (vmin[2]))) &&
+         ((isinf (vmax[0]) && !signbit (vmax[0])) &&
+          (isinf (vmax[1]) && !signbit (vmax[1])) &&
+          (isinf (vmax[2]) && !signbit (vmax[2])));
 #else
   graphene_simd4f_t neg_inf = graphene_simd4f_init (-INFINITY, -INFINITY, -INFINITY, 0.f);
   graphene_simd4f_t pos_inf = graphene_simd4f_init (INFINITY, INFINITY, INFINITY, 0.f);
diff --git a/src/graphene-ray.c b/src/graphene-ray.c
index e850e0b4..2b258e17 100644
--- a/src/graphene-ray.c
+++ b/src/graphene-ray.c
@@ -526,10 +526,10 @@ graphene_ray_intersect_box (const graphene_ray_t *r,
   /* These lines also handle the case where tx_min or tx_max is NaN
    * (result of 0 * INFINITY): NaN != NaN
    */
-#ifdef HAVE_ISNANF
-  if (ty_min > tx_min || isnanf (tx_min))
+#ifdef isnan
+  if (ty_min > tx_min || isnan (tx_min))
     tx_min = ty_min;
-  if (ty_max < tx_max || isnanf (tx_max))
+  if (ty_max < tx_max || isnan (tx_max))
     tx_max = ty_max;
 #else
   if (ty_min > tx_min || fpclassify (tx_min) == FP_NAN)
@@ -553,10 +553,10 @@ graphene_ray_intersect_box (const graphene_ray_t *r,
   if ((tx_min > tz_max) || (tz_min > tx_max))
     return GRAPHENE_RAY_INTERSECTION_KIND_NONE;
 
-#ifdef HAVE_ISNANF
-  if (tz_min > tx_min || isnanf (tx_min))
+#ifdef isnan
+  if (tz_min > tx_min || isnan (tx_min))
     tx_min = tz_min;
-  if (tz_max < tx_max || isnanf (tx_max))
+  if (tz_max < tx_max || isnan (tx_max))
     tx_max = tz_max;
 #else
   if (tz_min > tx_min || fpclassify (tx_min) == FP_NAN)
diff --git a/src/graphene-simd4f.c b/src/graphene-simd4f.c
index f3e03c7d..b3cc186b 100644
--- a/src/graphene-simd4f.c
+++ b/src/graphene-simd4f.c
@@ -1374,8 +1374,8 @@ approx_equal (float a,
               float b,
               float epsilon)
 {
-#ifdef HAVE_ISINFF
-  if (isinff (a) && isinff (b))
+#ifdef isinf
+  if (isinf (a) && isinf (b))
     return true;
 #else
   if (fpclassify (a) == FP_INFINITE && fpclassify (b) == FP_INFINITE)