[PATCH] D118765: [DAGCombiner] Fold SSHLSAT/USHLSAT to SHL when no saturation will occur

[Bjorn Pettersson via Phabricator via llvm-commits]

bjope updated this revision to Diff 406248.
bjope added a comment.

Updated after review feedback:

- Now using APInt for comparisons.
- For USHLSAT we now compare minimum number of known leading zeroes to the shift amount when checking if all shifted out bits are zero. That is hopefully easier to read/understand compared to using MaskedValueIsZero.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118765/new/

https://reviews.llvm.org/D118765

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/test/CodeGen/AArch64/sshl_sat.ll
  llvm/test/CodeGen/AArch64/ushl_sat.ll

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