[PATCH] D158850: RegisterCoalescer: Correctly set valid lanes when keeping live out implicit defs

[Bjorn Pettersson via Phabricator via llvm-commits]

bjope added inline comments.


================
Comment at: llvm/lib/CodeGen/RegisterCoalescer.cpp:2455
+      ErasableImplicitDef = false;
+      ValidLanes = TRI.getSubRegIndexLaneMask(ImpDef.getOperand(0).getSubReg());
+    }
----------------
If I understand correctly (well I'm trying to understand things), this is needed since we now want to treat the IMPLICIT_DEF as an ordinary value. And some previously computed ValidLanes values would be incorrect as it has treated the IMPLICIT_DEF as producing undefined values so we originally did not care about those lanes?




CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D158850/new/

https://reviews.llvm.org/D158850