- No longer insert BlockStart markers into asmlists. The presence of these markers disrupts peephole optimizations and require additional checks all over the place, causing various workarounds/hacks (like TAsmList.Create_without_marker) to start building up.

A more radical approach is to remove them altogether. Tested with i386-win32 (the oldest peephole optimizer), mips-linux (the newest one) and arm-linux (the most complex one) targets. The fallout was limited to two minor issues fixed in r28629 and r28708, respectively.

git-svn-id: trunk@28711 -

compiler/aasmdata.pas

@@ -122,8 +122,6 @@ interface
     type
       TAsmList = class(tlinkedlist)
          constructor create;
-         constructor create_without_marker;
-         function  empty : boolean;
          function  getlasttaifilepos : pfileposinfo;
       end;
 
@@ -284,20 +282,6 @@ implementation
     constructor TAsmList.create;
       begin
         inherited create;
-        { make sure the optimizer won't remove the first tai of this list}
-        insert(tai_marker.create(mark_BlockStart));
-      end;
-
-    constructor TAsmList.create_without_marker;
-      begin
-        inherited create;
-      end;
-
-    function TAsmList.empty : boolean;
-      begin
-        { there is always a mark_BlockStart available,
-          see TAsmList.create }
-        result:=(count<=1);
       end;
 
 

compiler/arm/aoptcpu.pas

@@ -2418,7 +2418,7 @@ Implementation
     begin
       result:=true;
 
-      list:=TAsmList.create_without_marker;
+      list:=TAsmList.create;
       p:=BlockStart;
       while p<>BlockEnd Do
         begin