skaller wrote:
On Mon, 2007-10-29 at 21:03 +0100, Andi Kleen wrote:
On Mon, Oct 29, 2007 at 03:51:27PM -0400, Robert Dewar wrote:
Sure, well nearly every optimization has some case where it is a
pessimization (one interesting thing that happens is that if you
change the length of generated code in *any* way you may be unlucky
and cause a systematic instruction cache miss in a loop, inlining
icache misses are hard in general and agreed the compiler cannot
do too much about them (except for trying not to generate too bloated
code in general)
BTW: doesn't this suggest unrolling loops and recursions is
potentially expensive?
Yes, of course! unrolling loops is often an overall loss
