Added intruction difference counter to peephole optimizer

phases/peephole.ml

@@ -1,3 +1,4 @@
+open Printf
 open Types
 open Util
 
@@ -54,12 +55,28 @@ let rec peephole = function
     | hd :: tl -> hd :: (peephole tl)
     | [] -> []
 
+(* Count actual instructions, ignoring comments and labels *)
+let count_instrs instrs =
+    let rec trav n = function
+    | [] -> n
+    | (Comment _ | Label _ | EmptyLine) :: tl -> trav n tl
+    | InlineComment (hd, _) :: tl -> trav (trav n [hd]) tl
+    | hd :: tl -> trav (n + 1) tl
+    in trav 0 instrs
+
 let phase input =
     match input with
     | Assembly instrs ->
         if args.optimize then (
             log_line 1 "- Peephole optimization";
-            Assembly (peephole (strip_comments instrs))
+            let oldcount = count_instrs instrs in
+            let instrs = peephole (strip_comments instrs) in
+            let newcount = count_instrs instrs in
+            log_line 1 (sprintf
+                "  Optimized %d to %d instructions (%d difference)"
+                oldcount newcount (newcount - oldcount)
+            );
+            Assembly instrs
         ) else
             input
     | _ -> raise (InvalidInput "peephole")