[PATCH] D30438: SplitKit: Correctly implement partial copies

[Krzysztof Parzyszek via Phabricator via llvm-commits]

kparzysz added inline comments.


================
Comment at: lib/CodeGen/SplitKit.cpp:572
+
+      if (BestIdx == 0)
+        report_fatal_error("Impossible to implement partial COPY");
----------------
MatzeB wrote:
> kparzysz wrote:
> > Would it make sense to add `|| BestCover <= 0`?
> `BestCover <= 0` can happen and is fine (it just means the best we could find is an index that covers more unnecessary lanes that we already covered anyway, than lanes we haven't covered yet).
Well, wasn't that the original problem, i.e. that we copied too much (which then ended up clobbering lanes marked as unused)?


Repository:
  rL LLVM

https://reviews.llvm.org/D30438