* patch by J. Gareth Moreton: EAX -> EDX:EAX sign extension shortcuts, and MOVSX shortcuts for AX register, part 2 of #36551

git-svn-id: trunk@43918 -

compiler/i386/aoptcpu.pas

@@ -324,6 +324,8 @@ unit aoptcpu;
                    end;
                 A_TEST, A_OR:
                   Result:=PostPeepholeOptTestOr(p);
+                A_MOVSX:
+                  Result:=PostPeepholeOptMOVSX(p);
                 else
                   ;
               end;

compiler/x86/aoptx86.pas

@@ -88,6 +88,7 @@ unit aoptx86;
         function PostPeepholeOptMovzx(var p : tai) : Boolean;
         function PostPeepholeOptXor(var p : tai) : Boolean;
 {$endif}
+        function PostPeepholeOptMOVSX(var p : tai) : boolean;
         function PostPeepholeOptCmp(var p : tai) : Boolean;
         function PostPeepholeOptTestOr(var p : tai) : Boolean;
         function PostPeepholeOptCall(var p : tai) : Boolean;
@@ -5033,6 +5034,50 @@ unit aoptx86;
       end;
 
 
+    function TX86AsmOptimizer.PostPeepholeOptMOVSX(var p : tai) : boolean;
+      begin
+        Result := False;
+        if not MatchOpType(taicpu(p), top_reg, top_reg) then
+          Exit;
+
+        { Convert:
+            movswl %ax,%eax  -> cwtl
+            movslq %eax,%rax -> cdqe
+
+            NOTE: Don't convert movswl %al,%ax to cbw, because cbw and cwde
+              refer to the same opcode and depends only on the assembler's
+              current operand-size attribute. [Kit]
+        }
+        with taicpu(p) do
+          case opsize of
+            S_WL:
+              if (oper[0]^.reg = NR_AX) and (oper[1]^.reg = NR_EAX) then
+                begin
+                  DebugMsg(SPeepholeOptimization + 'Converted movswl %ax,%eax to cwtl', p);
+                  opcode := A_CWDE;
+                  clearop(0);
+                  clearop(1);
+                  ops := 0;
+                  Result := True;
+                end;
+{$ifdef x86_64}
+            S_LQ:
+              if (oper[0]^.reg = NR_EAX) and (oper[1]^.reg = NR_RAX) then
+                begin
+                  DebugMsg(SPeepholeOptimization + 'Converted movslq %eax,%rax to cltq', p);
+                  opcode := A_CDQE;
+                  clearop(0);
+                  clearop(1);
+                  ops := 0;
+                  Result := True;
+                end;
+{$endif x86_64}
+            else
+              ;
+          end;
+      end;
+
+
     function TX86AsmOptimizer.PostPeepholeOptCmp(var p : tai) : Boolean;
       begin
         Result:=false;

compiler/x86_64/aoptcpu.pas

@@ -174,6 +174,8 @@ uses
               case taicpu(p).opcode of
                 A_MOV:
                   Result:=PostPeepholeOptMov(p);
+                A_MOVSX:
+                  Result:=PostPeepholeOptMOVSX(p);
                 A_MOVZX:
                   Result:=PostPeepholeOptMovzx(p);
                 A_CMP: