[Mono-bugs] [Bug 68723][Nor] Changed - Performance on long arith

bugzilla-daemon@bugzilla.ximian.com bugzilla-daemon@bugzilla.ximian.com
Sun, 24 Oct 2004 23:46:35 -0400 (EDT)

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Changed by bmaurer@users.sf.net.


--- shadow/68723	2004-10-24 23:12:36.000000000 -0400
+++ shadow/68723.tmp.15418	2004-10-24 23:46:35.000000000 -0400
@@ -118,6 +118,17 @@
 recursion->loop opts.
 ------- Additional Comments From writeonlymemory@gmail.com  2004-10-24 23:12 -------
 OK well I'll try to come up with a counter example when I have a
 minute (exam tomorrow) but if it was just floating point, wouldn't the
 O(n) one run slower? I mean, it's doing more floating point arithmetic...
+------- Additional Comments From bmaurer@users.sf.net  2004-10-24 23:46 -------
+Well, the recursive method does more complex ops per iteration than
+does the O(n). Mono is making the instructions more complex than they
+need to be, which may be why the O(n) method is faster.
+The problem here is that the long ops are an icall, so that we can use
+the gcc generated code. We could manually write the code for division
+and multiplication and have the jit know about it.
+Good luck on your exam.