Alias less registers

1 files changed, 38 insertions, 5 deletions

diff --git a/scheduling/MyRTLpathScheduleraux.ml b/scheduling/MyRTLpathScheduleraux.ml
index 2fb72d78..23d5d339 100644
--- a/scheduling/MyRTLpathScheduleraux.ml
+++ b/scheduling/MyRTLpathScheduleraux.ml
@@ -372,7 +372,11 @@ let restoration_instructions live_renames =
   in
   to_insert
 
-let restoration_instructions' live_renames ~next_free_reg =
+type restoration_actions =
+  | Just_restore of renamed
+  | Restore_and_alias of renamed
+
+let restoration_instructions' sb code live_renames ~next_free_reg =
   let next_free_reg =
     let next_free_reg = ref next_free_reg in
     (fun () ->
@@ -381,9 +385,35 @@ let restoration_instructions' live_renames ~next_free_reg =
       r )
   in
 
+  let length = Array.length sb.instructions in
+  let pc_to_idx =
+    Duplicateaux.generate_fwmap
+      (Array.to_list sb.instructions)
+      (List.init length (fun i -> i))
+      PTree.empty
+  in
+
+  let live_renames = PTree.map
+    (fun pc renames ->
+      let offset = apply_map' pc_to_idx pc in
+      List.map
+        (fun rename ->
+          let {old_name; new_name} = rename in
+          if used_before_redefinition sb code ~offset ~reg:old_name then
+            Restore_and_alias rename
+          else
+            Just_restore rename)
+        renames)
+    live_renames
+  in
+
   let to_rename = PTree.map1
     (fun renames ->
-      let old_names = List.map (fun {old_name; new_name} -> old_name) renames in
+      let old_names = List.filter_map (fun rename ->
+        match rename with
+        | Just_restore _ -> None
+        | Restore_and_alias {old_name; new_name} -> Some old_name) renames
+      in
       let aliases = List.init (List.length old_names) (fun _ -> next_free_reg ()) in
       let fwmap = Duplicateaux.generate_fwmap old_names aliases PTree.empty in
       fwmap
@@ -396,9 +426,12 @@ let restoration_instructions' live_renames ~next_free_reg =
       (fun to_insert side_exit_pc renames ->
         let alias_map = get_some @@ PTree.get side_exit_pc to_rename in
         let insts = ListLabels.map renames
-        ~f:(fun {old_name; new_name} ->
-          [ Iop (Op.Omove, [old_name], (apply_map' alias_map old_name), Camlcoq.P.one)
-          ; Iop (Op.Omove, [new_name], old_name, Camlcoq.P.one)])
+        ~f:(fun rename ->
+          match rename with
+          | Just_restore {old_name; new_name} -> [Iop (Op.Omove, [new_name], old_name, Camlcoq.P.one)]
+          | Restore_and_alias {old_name; new_name} ->
+            [ Iop (Op.Omove, [old_name], apply_map' alias_map old_name, Camlcoq.P.one)
+            ; Iop (Op.Omove, [new_name], old_name, Camlcoq.P.one)] )
         in
         let insts = List.flatten insts in
         InsertPositionMap.add (InsertPosition.Above side_exit_pc) insts to_insert)