Merge pull request #594 from JuliaSymbolics/b/replace_get!_with_get_t…

…o_avoid_unnecessary_initialization_of_state_values

Replace `get!` with `get` to avoid unnecessary initialization of state values

src/code.jl

@@ -743,7 +743,7 @@ end
 
 function cse_state!(state, t)
     !iscall(t) && return t
-    state[t] = Base.get!(state, t, 0) + 1
+    state[t] = Base.get(state, t, 0) + 1
     foreach(x->cse_state!(state, x), unsorted_arguments(t))
 end