Mention the codegen improvements

changelog/2.069.0_pre.dd

@@ -9,6 +9,7 @@ $(LI $(RELATIVE_LINK2 self-hosted-dmd, DMD has been ported to D.))
 $(LI $(RELATIVE_LINK2 objective-c-support, Basic support for Objective-C.))
 $(LI $(RELATIVE_LINK2 property-switch-deprecated, The $(TT -property) switch has
     been deprecated.))
+$(LI $(RELATIVE_LINK2 backend-improvements, DMD's codegen has improved.))
 )
 
 $(BUGSTITLE Library Changes,
@@ -64,6 +65,15 @@ $(LI $(LNAME2 property-switch-deprecated, The $(TT -property) switch has
     )
 )
 
+$(LI $(LNAME2 backend-improvements, DMD's codegen has improved.)
+
+    $(P Several improvements have been made to the backend's codegen. Parameters
+        and stack frame set up are optimized to use `SUB`/`MOV` instead of `PUSH`,
+        resulting in 30% faster code in some cases. Also, functions marked as
+        `nothrow` no longer generate a BP stack frame on Windows and Linux.
+    )
+)
+
 )
 
 $(BUGSTITLE Library Changes,