[Haskell-cafe] SpecConstr message while compiling

Hi, cafe! I wrote a program and had the following message while compiling (with -O2): SpecConstr Function `addOc{v s6RL} [lid]' has four call patterns, but the limit is 3 Use -fspec-constr-count=n to set the bound Use -dppr-debug to see specialisations What it means? Is it bad? It only happens when compiling with -O2. addOc is a local function (defined in a where clause). If it helps, here is the definition: addOc x [] = [(x,1)] addOc x ((y,n):ys) = if x == y then (y,n+1) : ys else (y,n) : addOc x ys I want to know if there is something wrong or a I don't need to take care about this. Thanks in advance, Daniel Díaz.