diff --git a/libs/libm/libm/lib_copysign.c b/libs/libm/libm/lib_copysign.c
index f0b6c8ad3b..171b476aaa 100644
--- a/libs/libm/libm/lib_copysign.c
+++ b/libs/libm/libm/lib_copysign.c
@@ -34,7 +34,7 @@
 #ifdef CONFIG_HAVE_DOUBLE
 double copysign(double x, double y)
 {
-  if (y < 0)
+  if (signbit(y))
     {
       return -fabs(x);
     }
diff --git a/libs/libm/libm/lib_copysignl.c b/libs/libm/libm/lib_copysignl.c
index 58d3a32067..824403904d 100644
--- a/libs/libm/libm/lib_copysignl.c
+++ b/libs/libm/libm/lib_copysignl.c
@@ -34,7 +34,7 @@
 #ifdef CONFIG_HAVE_LONG_DOUBLE
 long double copysignl(long double x, long double y)
 {
-  if (y < 0)
+  if (signbit(y))
     {
       return -fabsl(x);
     }