[llvm] [SandboxVec][DAG][NFC] Add comment about duplicate notes in deps() (PR #111915)

[via llvm-commits]

https://github.com/vporpo created https://github.com/llvm/llvm-project/pull/111915

None

>From dddebc61e888b105c2a52a13ed777efaa2252ccf Mon Sep 17 00:00:00 2001
From: Vasileios Porpodas <vporpodas at google.com>
Date: Thu, 10 Oct 2024 15:57:37 -0700
Subject: [PATCH] [SandboxVec][DAG][NFC] Add comment about duplicate notes in
 deps()

---
 .../Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h
index 7d300ea2b60d2d..5fa57efc1462e8 100644
--- a/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h
+++ b/llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/DependencyGraph.h
@@ -122,6 +122,10 @@ class DGNode {
   iterator preds_end(DependencyGraph &DAG) const {
     return const_cast<DGNode *>(this)->preds_end(DAG);
   }
+  /// \Returns a range of DAG predecessors nodes. If this is a MemDGNode then
+  /// this will also include the memory dependency predecessors.
+  /// Please note that this can include the same node more than once, if for
+  /// example it's both a use-def predecessor and a mem dep predecessor.
   iterator_range<iterator> preds(DependencyGraph &DAG) const {
     return make_range(preds_begin(DAG), preds_end(DAG));
   }