Le vendredi 10 février 2012 à 09:32 +0000, David Laight a écrit : > The generated code is particularly horrid for boolean arithmetic. > IIRC: > bool_var &= bool_var_1; > typically requires a sequence of compare and branch instructions. > I suggest you try to upgrade your old compiler and/or always check your assertions before posting on netdev such claims. bool_var &= bool_var_1; generates a single AND instruction, no compare, no branch. It would be a failure from compiler optimizer if that was the case. And (bool_var ? 1 : 0) or (!!bool_var) are NOP for a compiler as well. (Only one movzbl instruction to convert a byte to a word if context requires this) Only difference for bool or unsigned int vars is type promotion, and fact that compiler knows that 'bool' only can be 0 or 1, so allows more optimisations than plain "unsigned int". Really, bools are not evil if well used. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
