[PATCH] D47681: [DAGCombiner] Bug 31275- Extract a shift from a constant mul or udiv if a rotate can be formed

[Sam Conrad via Phabricator via llvm-commits]

sameconrad created this revision.
sameconrad added reviewers: RKSimon, craig.topper.

Attempt to extract a shrl from a udiv or a shl from a mul if this allows a rotate to be formed.  This targets cases where the input to a rotate pattern was a mul or udiv by a constant and InstCombine merged one of the shifts with the op.


Repository:
  rL LLVM

https://reviews.llvm.org/D47681

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/X86/rotate-extract.ll

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