llvm-project

15004214 - [GlobalISel] Add `sub(-1, x) -> (xor x, -1)` from SelectionDAG (#181014)

[GlobalISel] Add `sub(-1, x) -> (xor x, -1)` from SelectionDAG (#181014) This PR adds the pattern `// (sub -1, x) -> (xor x, -1)` to GlobalISel from SelectionDAG. Original SelectionDAG rewrite: https://github.com/llvm/llvm-project/blob/5b4811eddb28264ef1ccacc93c0f7d8cb0da31c8/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp#L4305 --------- Co-authored-by: Jay Foad <jay.foad@gmail.com>