Replace unreachable() with assert(false)

gcc/elna-tree.cc

@@ -249,4 +249,19 @@ namespace elna::gcc
 
         return label_decl;
     }
+
+    tree extract_constant(tree expression)
+    {
+        int code = TREE_CODE(expression);
+
+        if (code == CONST_DECL)
+        {
+            return DECL_INITIAL(expression);
+        }
+        else if (TREE_CODE_CLASS(code) == tcc_constant)
+        {
+            return expression;
+        }
+        return NULL_TREE;
+    }
 }