[llvm] [LV] Prefer DenseMap::lookup over find (NFC) (PR #141809)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon updated https://github.com/llvm/llvm-project/pull/141809

>From 5a5ebddfefd0a0885052899010a738101f44c608 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <r at artagnon.com>
Date: Wed, 28 May 2025 19:30:36 +0200
Subject: [PATCH 1/2] [LV] Prefer DenseMap::lookup over find (NFC)

---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 05b5764ffcafc..4baa7907178c7 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2566,9 +2566,9 @@ static Value *getExpandedStep(const InductionDescriptor &ID,
     return C->getValue();
   if (auto *U = dyn_cast<SCEVUnknown>(Step))
     return U->getValue();
-  auto I = ExpandedSCEVs.find(Step);
-  assert(I != ExpandedSCEVs.end() && "SCEV must be expanded at this point");
-  return I->second;
+  auto *V = ExpandedSCEVs.lookup(Step);
+  assert(V && "SCEV must be expanded at this point");
+  return V;
 }
 
 /// Knowing that loop \p L executes a single vector iteration, add instructions
@@ -10160,7 +10160,7 @@ preparePlanForEpilogueVectorLoop(VPlan &Plan, Loop *L,
     if (!ExpandR)
       continue;
     auto *ExpandedVal =
-        Plan.getOrAddLiveIn(ExpandedSCEVs.find(ExpandR->getSCEV())->second);
+        Plan.getOrAddLiveIn(ExpandedSCEVs.lookup(ExpandR->getSCEV()));
     ExpandR->replaceAllUsesWith(ExpandedVal);
     if (Plan.getTripCount() == ExpandR)
       Plan.resetTripCount(ExpandedVal);

>From e79fd2e17b383e2614defb679b750c020539795a Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Mon, 2 Jun 2025 15:04:28 +0100
Subject: [PATCH 2/2] [LV] Refine a couple of autos

---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 4baa7907178c7..26df5fff59568 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2566,7 +2566,7 @@ static Value *getExpandedStep(const InductionDescriptor &ID,
     return C->getValue();
   if (auto *U = dyn_cast<SCEVUnknown>(Step))
     return U->getValue();
-  auto *V = ExpandedSCEVs.lookup(Step);
+  Value *V = ExpandedSCEVs.lookup(Step);
   assert(V && "SCEV must be expanded at this point");
   return V;
 }
@@ -10159,7 +10159,7 @@ preparePlanForEpilogueVectorLoop(VPlan &Plan, Loop *L,
     auto *ExpandR = dyn_cast<VPExpandSCEVRecipe>(&R);
     if (!ExpandR)
       continue;
-    auto *ExpandedVal =
+    VPValue *ExpandedVal =
         Plan.getOrAddLiveIn(ExpandedSCEVs.lookup(ExpandR->getSCEV()));
     ExpandR->replaceAllUsesWith(ExpandedVal);
     if (Plan.getTripCount() == ExpandR)