fixup! Define HEAP_ALLOCED for CMM code

rts/include/rts/storage/HeapAlloc.h

@@ -69,6 +69,9 @@ struct mblock_address_range {
 } ATTRIBUTE_ALIGNED(64);
 extern struct mblock_address_range mblock_address_space;
 
+// This implementation is duplicated to `Cmm` because performing an `ccall` is relatively high
+// compared to the bounds check performed here. If this implementation changes the decisions should
+// be reevaluated.
 # define HEAP_ALLOCED(p)        ((W_)(p) >= mblock_address_space.begin && \
                                  (W_)(p) < (mblock_address_space.end))
 # define HEAP_ALLOCED_GC(p)     HEAP_ALLOCED(p)
@@ -79,6 +82,8 @@ extern struct mblock_address_range mblock_address_space;
 
 import mblock_address_space;
 
+// We explicitly duplicate the bound checking implementation of `HEAP_ALLOCED` for performance
+// reasons. It doesn't make sense to perform a `ccall` for such a simple implementation.
 # define HEAP_ALLOCED(p)        ((p) >= W_[mblock_address_space + WDS(0)] && \
                                  (p) <  W_[mblock_address_space + WDS(1)])