[llvm] [Vectorize] Avoid repeated hash lookups (NFC) (PR #132661)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/132661

None

>From 2be6684ad84b1cd77f706d333e805e47ab4b6972 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 23 Mar 2025 08:03:54 -0700
Subject: [PATCH] [Vectorize] Avoid repeated hash lookups (NFC)

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

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 92160a421e59c..ae55049c22338 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -5815,12 +5815,13 @@ LoopVectorizationCostModel::getReductionPatternCost(Instruction *I,
 
   // Test if the found instruction is a reduction, and if not return an invalid
   // cost specifying the parent to use the original cost modelling.
-  if (!InLoopReductionImmediateChains.count(RetI))
+  auto RetIIt = InLoopReductionImmediateChains.find(RetI);
+  if (RetIIt == InLoopReductionImmediateChains.end())
     return std::nullopt;
 
   // Find the reduction this chain is a part of and calculate the basic cost of
   // the reduction on its own.
-  Instruction *LastChain = InLoopReductionImmediateChains.at(RetI);
+  Instruction *LastChain = RetIIt->second;
   Instruction *ReductionPhi = LastChain;
   while (!isa<PHINode>(ReductionPhi))
     ReductionPhi = InLoopReductionImmediateChains.at(ReductionPhi);