[PATCH] D100884: Generalize getInvertibleOperand to support mismatched phi operand order

[Philip Reames via Phabricator via llvm-commits]

reames created this revision.
reames added a reviewer: nikic.
Herald added subscribers: hiraditya, mcrosier.
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Follow up to D99912 <https://reviews.llvm.org/D99912>, specifically the revert, fix, and reapply thereof.

By allowing mismatching operand numbers of the phi, we can recurse through a pair of phi recurrences whose operand orders have not been canonicalized.

After writing this, I started questioning the value of it.  This is a non-canonical form, and other optimization passes will canonicalize towards equal order.  Is the extra power really worth it?  I can see arguments on both sides, so curious what reviewers think.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100884

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Analysis/ValueTracking/known-non-equal.ll

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