Hrvoje> Do the added automatic variables make a difference? Unless the compiler is very stupid, adding a new auto variable can only make the code faster, not slower. C is not Elisp. At run time, an auto variable no longer exists, since it has been turned into just a memory reference (or a register reference). Computing an intermediate result would require the same code, and the compiler has the extra job of doing common subexpression elimination. It's dynamically scoped variables that makes variable references so expensive in Elisp, and another reason why rewriting a function from elisp to C can make it up to 30 times faster. But don't believe me - benchmark it! Martin