[PATCH] D110662: [GlobalISel] Combine mulo x, 2 -> addo x, x

[Jessica Paquette via Phabricator via llvm-commits]

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Similar to what SDAG does when it sees a smulo/umulo against 2 (see: `DAGCombiner::visitMULO`)

This pattern is fairly common in Swift code AFAICT.

Here's an example extracted from a Swift testcase:

https://godbolt.org/z/6cT8Mesx7


https://reviews.llvm.org/D110662

Files:
  llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
  llvm/include/llvm/Target/GlobalISel/Combine.td
  llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/combine-mulo-with-2.mir

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