elaboration avoid introducing illegal selects

src/Convert/Simplify.hs

@@ -34,13 +34,24 @@ convertDescription =
 traverseDeclM :: Decl -> State Info Decl
 traverseDeclM decl = do
     case decl of
-        Param Localparam _ x e -> modify $ Map.insert x e
+        Param Localparam _ x e ->
+            when (isSimpleExpr e) $ modify $ Map.insert x e
         _ -> return ()
     let mi = MIPackageItem $ Decl decl
     mi' <- traverseModuleItemM mi
     let MIPackageItem (Decl decl') = mi'
     return decl'
 
+isSimpleExpr :: Expr -> Bool
+isSimpleExpr Ident{}   = True
+isSimpleExpr PSIdent{} = True
+isSimpleExpr Number{}  = True
+isSimpleExpr String{}  = True
+isSimpleExpr (Dot   e _  ) = isSimpleExpr e
+isSimpleExpr (Bit   e _  ) = isSimpleExpr e
+isSimpleExpr (Range e _ _) = isSimpleExpr e
+isSimpleExpr _ = False
+
 traverseModuleItemM :: ModuleItem -> State Info ModuleItem
 traverseModuleItemM (Instance m p x rs l) = do
     p' <- mapM paramBindingMapper p

test/basic/simplify_func.sv

@@ -0,0 +1,15 @@
+package PKG;
+    typedef struct packed {
+        int F;
+    } S;
+    function automatic S f();
+        return '0;
+    endfunction
+endpackage
+
+module top;
+    localparam PKG::S L0 = PKG::f();
+    localparam int L1 = L0.F;
+    localparam int L2 = $clog2(L1);
+    initial $display("%b %b %b", L0, L1, L2);
+endmodule

test/basic/simplify_func.v

@@ -0,0 +1,6 @@
+module top;
+    localparam L0 = 0;
+    localparam L1 = L0;
+    localparam L2 = $clog2(L1);
+    initial $display("%b %b %b", L0, L1, L2);
+endmodule