[PATCH] D23007: [DAGCombiner] Better support for shifting large value type by constants

[Simon Pilgrim via llvm-commits]

RKSimon added a comment.

In https://reviews.llvm.org/D23007#508614, @t.p.northover wrote:

> Isn't the IR already undefined whenever this triggers (unless you're working on an i18446744073709551616)?


If the offending IR originated during dag combine then this is what should be reducing it to UNDEF. And when we are combining repeated shifts with the outer shift being valid then the inner shift might not have been reduced to UNDEF yet.


Repository:
  rL LLVM

https://reviews.llvm.org/D23007