[llvm] [Analysis] Avoid repeated hash lookups (NFC) (PR #126402)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/126402

>From 1fd503f0382c8e2087eff5d669a08f74a54038ab Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sat, 8 Feb 2025 14:36:20 -0800
Subject: [PATCH 1/2] [Analysis] Avoid repeated hash lookups (NFC)

---
 llvm/lib/Analysis/DependenceGraphBuilder.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Analysis/DependenceGraphBuilder.cpp b/llvm/lib/Analysis/DependenceGraphBuilder.cpp
index 7ee2adf49ebb410..82e9dcfbab23f3f 100644
--- a/llvm/lib/Analysis/DependenceGraphBuilder.cpp
+++ b/llvm/lib/Analysis/DependenceGraphBuilder.cpp
@@ -241,8 +241,8 @@ template <class G> void AbstractDependenceGraphBuilder<G>::createDefUseEdges() {
         if (!UI)
           continue;
         NodeType *DstNode = nullptr;
-        if (IMap.find(UI) != IMap.end())
-          DstNode = IMap.find(UI)->second;
+        if (auto It = IMap.find(UI); It != IMap.end())
+          DstNode = It->second;
 
         // In the case of loops, the scope of the subgraph is all the
         // basic blocks (and instructions within them) belonging to the loop. We

>From c3da5bbcecff01541ef4f6f027b3b12a59cd8972 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 9 Feb 2025 09:06:01 -0800
Subject: [PATCH 2/2] Address a comment.

---
 llvm/lib/Analysis/DependenceGraphBuilder.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/llvm/lib/Analysis/DependenceGraphBuilder.cpp b/llvm/lib/Analysis/DependenceGraphBuilder.cpp
index 82e9dcfbab23f3f..c076e52ce6e1451 100644
--- a/llvm/lib/Analysis/DependenceGraphBuilder.cpp
+++ b/llvm/lib/Analysis/DependenceGraphBuilder.cpp
@@ -240,9 +240,7 @@ template <class G> void AbstractDependenceGraphBuilder<G>::createDefUseEdges() {
         Instruction *UI = dyn_cast<Instruction>(U);
         if (!UI)
           continue;
-        NodeType *DstNode = nullptr;
-        if (auto It = IMap.find(UI); It != IMap.end())
-          DstNode = It->second;
+        NodeType *DstNode = IMap.lookup(UI);
 
         // In the case of loops, the scope of the subgraph is all the
         // basic blocks (and instructions within them) belonging to the loop. We