[PATCH] D118459: [ISEL] Canonicalize STEP_VECTOR to LHS if RHS is a splat.

[Paul Walker via Phabricator via llvm-commits]

paulwalker-arm added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:5629
+                                              SDValue &N2) const {
+  // Canonicalize constant to RHS if commutative.
+  if (!TLI->isCommutativeBinOp(Opcode))
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This comment is now out of date. I'd just remove the comment given you've moved the code into a function with `CommutativeBinop` in the name.


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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:5643
+  // Canonicalize:
+  //  binop(splat(X), stepvector) -> binop(stepvector, splat(X))
+  //
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What about changing this to `binop(splat(x), not_splat(y))` -> `binop(not_splat(y), splat(x))`?  That would solve your problem and be truly canonical.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118459/new/

https://reviews.llvm.org/D118459