[PATCH] D154522: [DAG] Improve combineCarryDiamond to accept (uaddo_carry X, 0, Carry)

[Amaury SECHET via Phabricator via llvm-commits]

deadalnix created this revision.
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It turns out that `(uaddo X, Carry)` is tranformed into `(uaddo_carry X, 0, Carry)` whenever the carry is an actual carry. This defeats the pattern matched by `combineCarryDiamond` when the uaddo is combined before `combineCarryDiamond` had the chance to do its magic.

This is exhibited in D152928 <https://reviews.llvm.org/D152928> but I have not been able to reliably tirgger that error on main.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154522

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

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