[PATCH] D41463: [CodeGen] Add a new pass to sink Copy instructions after RA

[Sean Fertile via Phabricator via llvm-commits]

sfertile added a comment.

In https://reviews.llvm.org/D41463#982337, @junbuml wrote:

> In my environment, Xalan is sensitive in code alignment. I open see some small change which is not even applied in hot functions could impact on score in range of 3~4%.  I'm not sure if this is also your case.  Can you please share how this change impact on hot functions (AFAIK, Xalan has two hot functions). It will be great if you can share any suspicious sinking or transformations caused by sinking copies.


I spent some more time profiling this. I think your right on the code alignment causing the degradation. I've seen this before with Xalan but never with this big of a difference. I can trace the slow down to 2 functions that didn't change with this patch.


https://reviews.llvm.org/D41463