diff --git a/libs/pbd3/pbd/fastlog.h b/libs/pbd3/pbd/fastlog.h
index 4e9050cb8b..4269705a44 100644
--- a/libs/pbd3/pbd/fastlog.h
+++ b/libs/pbd3/pbd/fastlog.h
@@ -11,14 +11,16 @@ static inline float fast_log2 (float val)
 	/* don't use reinterpret_cast<> because that prevents this
 	   from being used by pure C code (for example, GnomeCanvasItems)
 	*/
-	int * const    exp_ptr = (int *)(&val);
+	union {float f; int i;} t;
+	t.f = val;
+	int * const    exp_ptr =  &t.i;
 	int            x = *exp_ptr;
 	const int      log_2 = ((x >> 23) & 255) - 128;
 	x &= ~(255 << 23);
 	x += 127 << 23;
 	*exp_ptr = x;
 	
-	val = ((-1.0f/3) * val + 2) * val - 2.0f/3;   // (1)
+	val = ((-1.0f/3) * t.f + 2) * t.f - 2.0f/3;
 	
 	return (val + log_2);
 }