+#if defined(__APPLE__)
+inline int
+FloorLog2(size_t x)
+{
+ assert(x > 0);
+ assert(sizeof(size_t) == 4 || sizeof(size_t) == 8);
+
+ // It's my hope that this is optimized away?
+ if (sizeof(size_t) == 4)
+ return FloorLog2((uint32_t)x);
+ else if (sizeof(size_t) == 8)
+ return FloorLog2((uint64_t)x);
+
+}
+#endif
+