[PATCH] D135022: [GlobalISel] Implement undef combines for funnel shifts

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

Doesn't remove whatever was incorrectly folding this before



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Comment at: llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h:763-764
+  /// fshr (x, y, undef) -> y for scalars
+  /// fshl (x, y, undef) -> undef for vectors
+  /// fshr (x, y, undef) -> undef for vectors
+  void applyUndefFunnelShiftAmount(MachineInstr &MI);
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Different behavior for vector and scalar sounds really broken


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135022/new/

https://reviews.llvm.org/D135022