[llvm] SelectionDAG: Add missing AddNodeIDCustom case for MDNodeSDNode. (PR #136805)

[Peter Collingbourne via llvm-commits]

https://github.com/pcc created https://github.com/llvm/llvm-project/pull/136805

Without this we ended up never deduplicating MDNodeSDNodes.


>From 1e3181c7b7ec0c35cfd211a9540f96059b83e1ec Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter at pcc.me.uk>
Date: Tue, 22 Apr 2025 20:54:15 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.6-beta.1
---
 llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index a41efd58ce4e4..0a2687a16a80c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -967,6 +967,9 @@ static void AddNodeIDCustom(FoldingSetNodeID &ID, const SDNode *N) {
   case ISD::INTRINSIC_W_CHAIN:
     // Handled by MemIntrinsicSDNode check after the switch.
     break;
+  case ISD::MDNODE_SDNODE:
+    ID.AddPointer(cast<MDNodeSDNode>(N)->getMD());
+    break;
   } // end switch (N->getOpcode())
 
   // MemIntrinsic nodes could also have subclass data, address spaces, and flags