On Fri, 2013-03-22 at 13:00 -0600, Jeff Law wrote: > As others have pointed out, this is jump threading. > > The reason you're not seeing jump threading in the CoreMark test is the > switch is inside a loop and threading a backedge is severely constrained. > > There's a BZ for this issue with a bit more state for this issue. > > jeff
It took me a minute to map BZ to bugzilla, but I assume you mean there is a bugzilla report with information on this issue, I'll look around to see what I can find. The example I gave was a simple case and ideally the duplicated code (codeX) could have other edges leading into or out of it without that preventing the jump threading. But it sounds like it does prevent it with the current implementation of jump threading. Maybe it is just the presence of a back edge that is preventing it. I will look more into the GCC implementation and what constraints there are and why they prevent its use in CoreMark. Steve Ellcey sell...@imgtec.com
