[llvm] [NFC] add explanation to register flags doc (PR #91803)

[Florian Mayer via llvm-commits]

https://github.com/fmayer updated https://github.com/llvm/llvm-project/pull/91803

>From d000fdc6cc18421465b012326dbac2efba0e7c3d Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer at google.com>
Date: Fri, 10 May 2024 13:27:04 -0700
Subject: [PATCH 1/3] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
 =?UTF-8?q?itial=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.4
---
 llvm/docs/MIRLangRef.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/llvm/docs/MIRLangRef.rst b/llvm/docs/MIRLangRef.rst
index 52ff24daa7fba..c617e4661a5fb 100644
--- a/llvm/docs/MIRLangRef.rst
+++ b/llvm/docs/MIRLangRef.rst
@@ -545,36 +545,47 @@ corresponding internal ``llvm::RegState`` representation:
 
    * - Flag
      - Internal Value
+     - Meaning
 
    * - ``implicit``
      - ``RegState::Implicit``
+     - Not emitted register (e.g. carry, or temporary result).
 
    * - ``implicit-def``
      - ``RegState::ImplicitDefine``
+     - `implicit` and `def`
 
    * - ``def``
      - ``RegState::Define``
+     - Register definition.
 
    * - ``dead``
      - ``RegState::Dead``
+     - Unused definition.
 
    * - ``killed``
      - ``RegState::Kill``
+     - The last use of a register.
 
    * - ``undef``
      - ``RegState::Undef``
+     - Value of the register doesn't matter.
 
    * - ``internal``
      - ``RegState::InternalRead``
+     - Register reads a value that is defined inside the same instruction or bundle.
 
    * - ``early-clobber``
      - ``RegState::EarlyClobber``
+     - Register definition happens before uses.
 
    * - ``debug-use``
      - ``RegState::Debug``
+     - Register 'use' is for debugging purpose.
 
    * - ``renamable``
      - ``RegState::Renamable``
+     - Register that may be renamed.
 
 .. _subregister-indices:
 

>From ab45f63672c4e70ca01d129a1dc3e3347996903a Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer at google.com>
Date: Fri, 10 May 2024 13:29:35 -0700
Subject: [PATCH 2/3] vhsnh

Created using spr 1.3.4
---
 llvm/docs/MIRLangRef.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/docs/MIRLangRef.rst b/llvm/docs/MIRLangRef.rst
index c617e4661a5fb..41df88b629633 100644
--- a/llvm/docs/MIRLangRef.rst
+++ b/llvm/docs/MIRLangRef.rst
@@ -553,7 +553,7 @@ corresponding internal ``llvm::RegState`` representation:
 
    * - ``implicit-def``
      - ``RegState::ImplicitDefine``
-     - `implicit` and `def`
+     - ``implicit`` and ``def``
 
    * - ``def``
      - ``RegState::Define``

>From 6dab9ff72a1410989553285490f2a077c707c855 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer at google.com>
Date: Tue, 14 May 2024 11:15:03 -0700
Subject: [PATCH 3/3] add comment to keep in sync

---
 llvm/docs/MIRLangRef.rst | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/docs/MIRLangRef.rst b/llvm/docs/MIRLangRef.rst
index 41df88b629633..7309e7b68b86a 100644
--- a/llvm/docs/MIRLangRef.rst
+++ b/llvm/docs/MIRLangRef.rst
@@ -540,6 +540,9 @@ Register Flags
 The table below shows all of the possible register flags along with the
 corresponding internal ``llvm::RegState`` representation:
 
+..
+   Keep this in sync with MachineInstrBuilder.h
+
 .. list-table::
    :header-rows: 1