diff --git a/.gitattributes b/.gitattributes
index 67493d0ead..6bf8a1c5fb 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -18408,6 +18408,7 @@ tests/webtbs/tw3742.pp svneol=native#text/plain
 tests/webtbs/tw37427.pp svneol=native#text/pascal
 tests/webtbs/tw37449.pp svneol=native#text/pascal
 tests/webtbs/tw37468.pp svneol=native#text/pascal
+tests/webtbs/tw37477.pp svneol=native#text/pascal
 tests/webtbs/tw37493.pp svneol=native#text/pascal
 tests/webtbs/tw3751.pp svneol=native#text/plain
 tests/webtbs/tw3758.pp svneol=native#text/plain
diff --git a/compiler/optcse.pas b/compiler/optcse.pas
index 8e5821413d..5337339171 100644
--- a/compiler/optcse.pas
+++ b/compiler/optcse.pas
@@ -307,7 +307,10 @@ unit optcse;
       begin
         result:=fen_false;
         nodes:=nil;
-        if n.nodetype in cseinvariant then
+        if (n.nodetype in cseinvariant) and
+          { a setelement node is cseinvariant, but it might not be replaced by a block so
+            it cannot be the root of the cse search }
+          (n.nodetype<>setelementn) then
           begin
             csedomain:=true;
             foreachnodestatic(pm_postprocess,n,@searchsubdomain,@csedomain);
diff --git a/tests/webtbs/tw37477.pp b/tests/webtbs/tw37477.pp
new file mode 100644
index 0000000000..714d91395c
--- /dev/null
+++ b/tests/webtbs/tw37477.pp
@@ -0,0 +1,6 @@
+{ %OPT=-O3 }
+{ %norun }
+var a : integer;
+begin
+    write(a = a in[a in[a], a / 0 > a])
+end.