Issue 173033
Summary [VectorCombine] foldPermuteOfBinops - support multiple uses of shuffled binop
Labels good first issue, missed-optimization, llvm::vectorcombine
Assignees
Reporter RKSimon
    The "shuffle (binop (shuffle, shuffle)), undef" -->  "binop (shuffle), (shuffle)" fold is currently limited by mOneUse checks:

https://github.com/llvm/llvm-project/blob/ba55ef32ef9214804b421090767a27f14abd9439/llvm/lib/Transforms/Vectorize/VectorCombine.cpp#L2280-L2300

We should try to remove the m_OneUse limits (binop and the inner shuffles) and adjust the NewCost accordingly - similar to what happens in foldShuffleOfCastops

A large portion of this task will be creating test coverage.
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