[PATCH] D40308: [RegisterCoalescer] More fixes for subreg join failure in RegCoalescer

[Quentin Colombet via Phabricator via llvm-commits]

qcolombet added a comment.

Hi David,

> If not I'll land in the next few days.

Please don't do that. When a patch is up for review you're basically need someone to look at it before pushing it.

As for the patch itself, it looks reasonable, but before going further I'd like we understand why the .mir test doesn't reproduce it.
I am suspecting that what you're fixing is a somewhat invalid from of live-ranges that has been introduced by a bug in some previous updates of the liveness information.

Could you go to the bottom of this?

Cheers,
-Quentin



================
Comment at: lib/CodeGen/RegisterCoalescer.cpp:592
+    // Check for SubRange Segments of the form [1234r,1234d:0) which can be
+    // removed to prevent creating bogus SubRange Segments
+    LiveInterval::iterator SS = S.FindSegmentContaining(CopyIdx);
----------------
Period at the end of comments.


https://reviews.llvm.org/D40308