[all-commits] [llvm/llvm-project] 28cb90: [NFC][CodeGen] Add comments for SDNode debug ID

[Daniil Kovalev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 28cb9081f8cb686c7a8171477b00afc344c3d10a
      https://github.com/llvm/llvm-project/commit/28cb9081f8cb686c7a8171477b00afc344c3d10a
  Author: Daniil Kovalev <daniil at kovalev.website>
  Date:   2022-04-06 (Wed, 06 Apr 2022)

  Changed paths:
    M llvm/include/llvm/CodeGen/SelectionDAG.h
    M llvm/include/llvm/CodeGen/SelectionDAGNodes.h

  Log Message:
  -----------
  [NFC][CodeGen] Add comments for SDNode debug ID

Normally, we place fields serving for debug purpose declarations
under `#if LLVM_ENABLE_ABI_BREAKING_CHECKS`. For `SDNode::PersistentId` and
`SelectionDAG::NextPersistentId`, we do not want to do so because it adds
unneeded complexity without noticeable benefits (see discussion with @thakis
in D120714). This patch adds comments describing why we don't place those
fields under `#if` not to confuse anyone more.

Differential Revision: https://reviews.llvm.org/D123238