[all-commits] [llvm/llvm-project] c75870: [LLVM][Casting.h] Add ForwardToPointerCast trait

[Aman LaChapelle via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c7587080188e1f46ddf8b8274e99d4481361d5dc
      https://github.com/llvm/llvm-project/commit/c7587080188e1f46ddf8b8274e99d4481361d5dc
  Author: bzcheeseman <aman.lachapelle at gmail.com>
  Date:   2022-05-13 (Fri, 13 May 2022)

  Changed paths:
    M llvm/include/llvm/Support/Casting.h

  Log Message:
  -----------
  [LLVM][Casting.h] Add ForwardToPointerCast trait

Addresses use cases in Clang/MLIR that need pointer-to-pointer, reference-to-reference, and value-to-value casts from/to the same types. This should reduce boilerplate by allowing the user to simply specify the pointer cast and forward the reference cast directly to the pointer cast.

This cast trait DOES NOT implement `castFailed` and `doCastIfPossible` because in the general case doing so could result in a nullptr dereference. Users can use `NullableValueCastFailed` and `DefaultDoCastIfPossible` as desired for those cases where `nullptr` is acceptable.

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D125576