On Thu, 8 Jan 2009, H. Peter Anvin wrote: > > Right. gcc simply doesn't have any way to know how heavyweight an > asm() statement is I don't think that's relevant. First off, gcc _does_ have a perfectly fine notion of how heavy-weight an "asm" statement is: just count it as a single instruction (and count the argument setup cost that gcc _can_ estimate). That would be perfectly fine. If people use inline asms, they tend to use it for a reason. However, I doubt that it's the inline asm that was the biggest reason why gcc decided not to inline - it was probably the constant "switch()" statement. The inline function actually looks pretty large, if it wasn't for the fact that we have a constant argument, and that one makes the switch statement go away. I suspect gcc has some pre-inlining heuristics that don't take constant folding and simplifiation into account - if you look at just the raw tree of the function without taking the optimization into account, it will look big. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
