[PATCH] D46505: [DAGcombine] Teach the combiner about -a = ~a + 1

[Amaury SECHET via Phabricator via llvm-commits]

deadalnix created this revision.
deadalnix added reviewers: efriedma, spatel, RKSimon, zvi, bkramer.
Herald added a subscriber: llvm-commits.

This include variant for add, uaddo and addcarry. usubo and subcarry require the carry to be flipped to preserve semantic, but we chose to do the transform anyway in that case as to push the transform down the carry chain.


Repository:
  rL LLVM

https://reviews.llvm.org/D46505

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/X86/subcarry.ll

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