* when optimizing temp assignments by simply replacing one temp with

another, it's not enough that the temp sizes are the same, because
    the assignment may only apply to part of them. In such cases,
    perform a regular copy (mantis #13948)

git-svn-id: trunk@13255 -

.gitattributes

@@ -9158,6 +9158,7 @@ tests/webtbs/tw13763.pp svneol=native#text/plain
 tests/webtbs/tw13813.pp svneol=native#text/plain
 tests/webtbs/tw13820.pp svneol=native#text/plain
 tests/webtbs/tw13890.pp svneol=native#text/plain
+tests/webtbs/tw13948.pp svneol=native#text/plain
 tests/webtbs/tw1398.pp svneol=native#text/plain
 tests/webtbs/tw1401.pp svneol=native#text/plain
 tests/webtbs/tw1407.pp svneol=native#text/plain

compiler/ncgld.pas

@@ -116,6 +116,14 @@ implementation
                   result := fen_norecurse_true;
                 end;
             end;
+          { Subscriptn must be rejected, otherwise we may replace an
+            an entire record with a temp for its first field, mantis #13948)
+            Exception: the field's size is the same as the entire record
+          }
+          subscriptn:
+            if not(tsubscriptnode(n).left.resultdef.typ in [recorddef,objectdef]) or
+               (tsubscriptnode(n).left.resultdef.size <> tsubscriptnode(n).resultdef.size) then
+              result := fen_norecurse_false;
           { optimize the searching a bit }
           derefn,addrn,
           calln,inlinen,casen,

tests/webtbs/tw13948.pp

@@ -0,0 +1,31 @@
+{ %opt=-O2 }
+
+type
+  tr = record
+    a,b: longint;
+  end;
+
+function f: tr;
+begin
+  f.a:=5;
+  f.b:=6;
+end;
+
+procedure test;
+var
+  r: tr;
+begin
+  r.a:=1;
+  r.b:=2;
+  r.a:=f.a;
+  writeln(r.a);
+  writeln(r.b);
+  if (r.a<>5) then
+    halt(1);
+  if (r.b<>2) then
+    halt(2);
+end;
+
+begin
+  test;
+end.