Erik Eckstein 0a71d0fbea SimplifyCFG: allow jump-threading for switch_enum_data_addr instructions. ...

If the branch-block injects a certain enum case and the destination switches on that enum, it's worth jump threading. E.g.

  inject_enum_addr %enum : $*Optional<T>, #Optional.some
  ... // no memory writes here
  br DestBB
DestBB:
  ... // no memory writes here
  switch_enum_addr %enum : $*Optional<T>, case #Optional.some ...

This enables removing all code with optionals in a loop, which iterates over an array of address-only elements, e.g.

  func test<T>(_ items: [T]) {
    for i in items {
      print(i)
    }
  }

2020-09-30 16:44:58 +02:00

2.8 KiB

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