[polly] [Polly] Remove unused DenseMapInfo::getEmptyKey (PR #201992)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/201992

After #201281 DenseMapInfo<T>::getEmptyKey() is no longer used by
DenseMap. Remove the unused getEmptyKey definitions and dead sentinel
uses.


>From befbaf063c004cee04387a8812be1f3308f3cc6b Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Fri, 5 Jun 2026 19:08:16 -0700
Subject: [PATCH] [Polly] Remove unused DenseMapInfo::getEmptyKey

After #201281 DenseMapInfo<T>::getEmptyKey() is no longer used by
DenseMap. Remove the unused getEmptyKey definitions and dead sentinel
uses.
---
 polly/include/polly/Support/VirtualInstruction.h | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/polly/include/polly/Support/VirtualInstruction.h b/polly/include/polly/Support/VirtualInstruction.h
index a9792840bf4f7..23fd86bc73c58 100644
--- a/polly/include/polly/Support/VirtualInstruction.h
+++ b/polly/include/polly/Support/VirtualInstruction.h
@@ -322,13 +322,6 @@ template <> struct DenseMapInfo<polly::VirtualInstruction> {
                                                 RHS.getInstruction());
   }
 
-  static polly::VirtualInstruction getEmptyKey() {
-    polly::VirtualInstruction EmptyKey;
-    EmptyKey.Stmt = DenseMapInfo<polly::ScopStmt *>::getEmptyKey();
-    EmptyKey.Inst = DenseMapInfo<Instruction *>::getEmptyKey();
-    return EmptyKey;
-  }
-
   static unsigned getHashValue(polly::VirtualInstruction Val) {
     return DenseMapInfo<std::pair<polly::ScopStmt *, Instruction *>>::
         getHashValue(std::make_pair(Val.getStmt(), Val.getInstruction()));