Andy Reitz wrote: > So, clearly, something is optimizing the pow() function away when the > arguments are hard-coded lvalues, instead of varibles. > > Now, what that thing *is*, I don't know.
The C compiler precomputes constant expressions; your "pow(2,3)" is being rewritten to "8" by the compiler. Similarly, if you write "1 + 2 / 3 + 4 * 5 - 6", the C compiler will turn this into "15" rather than producing a series of instructions which computes the expression. When you reference variables, this optimization isn't possible, since those variables might be modified before you reach the line where they are used. (Obviously this doesn't happen in your program, but the compiler isn't smart enough to figure that out.) Colin Percival _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"