[llvm] [Utils] Avoid repeated hash lookups (NFC) (PR #127171)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/127171

None

>From 2b00bf34ab9a05105bab35999a6dcfcaff1cf733 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Thu, 13 Feb 2025 09:19:09 -0800
Subject: [PATCH] [Utils] Avoid repeated hash lookups (NFC)

---
 llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
index 89cfee2acd82c..054b0ba2ba664 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
@@ -395,8 +395,9 @@ llvm::UnrollAndJamLoop(Loop *L, unsigned Count, unsigned TripCount,
       }
 
       // Update our running maps of newest clones
-      PrevItValueMap[New] = (It == 1 ? *BB : LastValueMap[*BB]);
-      LastValueMap[*BB] = New;
+      auto &Last = LastValueMap[*BB];
+      PrevItValueMap[New] = (It == 1 ? *BB : Last);
+      Last = New;
       for (ValueToValueMapTy::iterator VI = VMap.begin(), VE = VMap.end();
            VI != VE; ++VI) {
         PrevItValueMap[VI->second] =