[PATCH] D48478: [RegisterCoalescer] Improve handling of COPY instructions with identical value numbers

[Krzysztof Parzyszek via Phabricator via llvm-commits]

kparzysz added a comment.

I don't want to be spending time reviewing more alternatives at this point.  I'm familiar with what I've started and I fixed all known problems.  I still need to analyze the problems in detail either way and reviewing additional patches is just more work for me.



================
Comment at: lib/CodeGen/RegisterCoalescer.cpp:1647
   }
+  if (CopyMI->isImplicitDef()) {
+    // Not coalesceable; eliminateUndefCopy turned it into implicit_def.
----------------
I have fixed this differently in the previous review.


================
Comment at: lib/CodeGen/RegisterCoalescer.cpp:2830
+    // liveness was extended as we expected.
+    SmallVector<std::pair<SlotIndex, SlotIndex>, 8> PrunedDefs;
+
----------------
This is an overkill.


Repository:
  rL LLVM

https://reviews.llvm.org/D48478