[llvm] [SCEV] Avoid repeated hash lookups (NFC) (PR #112656)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/112656

None

>From 6bee188ed66dc79e09760f12be473a4668106394 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Wed, 16 Oct 2024 06:50:11 -0700
Subject: [PATCH] [SCEV] Avoid repeated hash lookups (NFC)

---
 llvm/lib/Analysis/ScalarEvolution.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index a3ba8e03781910..61ec336c8548cc 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -9662,14 +9662,14 @@ Constant *
 ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
                                                    const APInt &BEs,
                                                    const Loop *L) {
-  auto I = ConstantEvolutionLoopExitValue.find(PN);
-  if (I != ConstantEvolutionLoopExitValue.end())
+  auto [I, Inserted] = ConstantEvolutionLoopExitValue.try_emplace(PN);
+  if (!Inserted)
     return I->second;
 
   if (BEs.ugt(MaxBruteForceIterations))
-    return ConstantEvolutionLoopExitValue[PN] = nullptr;  // Not going to evaluate it.
+    return nullptr; // Not going to evaluate it.
 
-  Constant *&RetVal = ConstantEvolutionLoopExitValue[PN];
+  Constant *&RetVal = I->second;
 
   DenseMap<Instruction *, Constant *> CurrentIterVals;
   BasicBlock *Header = L->getHeader();