[llvm] [Coroutines] Avoid repeated hash lookups (NFC) (PR #126466)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/126466

None

>From a1dcb565347f7788d4e4a473a63e2a5ef3b6bf3d Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 9 Feb 2025 13:52:17 -0800
Subject: [PATCH] [Coroutines] Avoid repeated hash lookups (NFC)

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

diff --git a/llvm/lib/Transforms/Coroutines/MaterializationUtils.cpp b/llvm/lib/Transforms/Coroutines/MaterializationUtils.cpp
index 3686c7c153999cb..5021425152f6cc0 100644
--- a/llvm/lib/Transforms/Coroutines/MaterializationUtils.cpp
+++ b/llvm/lib/Transforms/Coroutines/MaterializationUtils.cpp
@@ -70,11 +70,12 @@ struct RematGraph {
                std::deque<std::unique_ptr<RematNode>> &WorkList,
                User *FirstUse) {
     RematNode *N = NUPtr.get();
-    if (Remats.count(N->Node))
+    auto [It, Inserted] = Remats.try_emplace(N->Node);
+    if (!Inserted)
       return;
 
     // We haven't see this node yet - add to the list
-    Remats[N->Node] = std::move(NUPtr);
+    It->second = std::move(NUPtr);
     for (auto &Def : N->Node->operands()) {
       Instruction *D = dyn_cast<Instruction>(Def.get());
       if (!D || !MaterializableCallback(*D) ||