[PATCH] D47725: [SelectionDAG] Provide default expansion for rotates

Eli Friedman via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Jun 8 12:17:04 PDT 2018


efriedma added a comment.

Hmm... yes, I guess the AND isn't necessary if the shift produces either zero or the input, which is true for every target I can think of.  But `(SHL x, 32)` is defined to produce undef for a 32-bit input, not some target-specific result, so you can't depend on that.  Might make sense to add a dedicated target-independent opcode to represent it.


Repository:
  rL LLVM

https://reviews.llvm.org/D47725





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