[llvm] [SCCP] Use Small Vector for struct (PR #226638)

[via llvm-commits]

https://github.com/aokblast created https://github.com/llvm/llvm-project/pull/226638

None

>From be7d200665e4b90b2e4d7977bef350202c62aa68 Mon Sep 17 00:00:00 2001
From: ShengYi Hung <aokblast at FreeBSD.org>
Date: Sat, 26 Sep 2026 00:17:07 -0500
Subject: [PATCH] [SCCP] Use Small Vector for struct

---
 llvm/include/llvm/Transforms/Utils/SCCPSolver.h |  2 +-
 llvm/lib/Transforms/Utils/SCCPSolver.cpp        | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Utils/SCCPSolver.h b/llvm/include/llvm/Transforms/Utils/SCCPSolver.h
index 88a4df83304f1a..2200c8c0ce51e6 100644
--- a/llvm/include/llvm/Transforms/Utils/SCCPSolver.h
+++ b/llvm/include/llvm/Transforms/Utils/SCCPSolver.h
@@ -137,7 +137,7 @@ class SCCPSolver {
   // block to the 'To' basic block is currently feasible.
   LLVM_ABI bool isEdgeFeasible(BasicBlock *From, BasicBlock *To) const;
 
-  LLVM_ABI std::vector<ValueLatticeElement>
+  LLVM_ABI SmallVector<ValueLatticeElement, 4>
   getStructLatticeValueFor(Value *V) const;
 
   LLVM_ABI void removeLatticeValueFor(Value *V);
diff --git a/llvm/lib/Transforms/Utils/SCCPSolver.cpp b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
index 114389ff057a7e..a570afb728c056 100644
--- a/llvm/lib/Transforms/Utils/SCCPSolver.cpp
+++ b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -972,8 +972,8 @@ class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
 
   bool isEdgeFeasible(BasicBlock *From, BasicBlock *To) const;
 
-  std::vector<ValueLatticeElement> getStructLatticeValueFor(Value *V) const {
-    std::vector<ValueLatticeElement> StructValues;
+  SmallVector<ValueLatticeElement, 4> getStructLatticeValueFor(Value *V) const {
+    SmallVector<ValueLatticeElement, 4> StructValues;
     auto *STy = dyn_cast<StructType>(V->getType());
     assert(STy && "getStructLatticeValueFor() can be called only on structs");
     for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
@@ -1209,10 +1209,10 @@ Constant *SCCPInstVisitor::getConstant(const ValueLatticeElement &LV,
 Constant *SCCPInstVisitor::getConstantOrNull(Value *V) const {
   Constant *Const = nullptr;
   if (V->getType()->isStructTy()) {
-    std::vector<ValueLatticeElement> LVs = getStructLatticeValueFor(V);
+    SmallVector<ValueLatticeElement, 4> LVs = getStructLatticeValueFor(V);
     if (any_of(LVs, SCCPSolver::isOverdefined))
       return nullptr;
-    std::vector<Constant *> ConstVals;
+    SmallVector<Constant *, 4> ConstVals;
     auto *ST = cast<StructType>(V->getType());
     for (unsigned I = 0, E = ST->getNumElements(); I != E; ++I) {
       const ValueLatticeElement &LV = LVs[I];
@@ -2448,7 +2448,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) const {
   return Visitor->isEdgeFeasible(From, To);
 }
 
-std::vector<ValueLatticeElement>
+SmallVector<ValueLatticeElement, 4>
 SCCPSolver::getStructLatticeValueFor(Value *V) const {
   return Visitor->getStructLatticeValueFor(V);
 }