From ec37ebf59be78665caa679d46607a2f054155c55 Mon Sep 17 00:00:00 2001
From: Jessica Paquette <jpaquette@apple.com>
Date: Fri, 3 Feb 2023 16:08:50 -0800
Subject: [PATCH] [NFC] Use SmallVector/ArrayRef in MachineOutliner/SuffixTree
 for small types

The MachineOutliner + SuffixTree both used `std::vector` everywhere because I
didn't know any better at the time.

At least for small types, such as `unsigned` and iterators, I can't see any
particular reason to use std::vector over `SmallVector` here.
---
 llvm/include/llvm/Support/SuffixTree.h |  8 ++++----
 llvm/lib/CodeGen/MachineOutliner.cpp   | 16 ++++++++--------
 llvm/lib/Support/SuffixTree.cpp        |  4 ++--
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/llvm/include/llvm/Support/SuffixTree.h b/llvm/include/llvm/Support/SuffixTree.h
index 162a1de72f1a..70a12efd4a10 100644
--- a/llvm/include/llvm/Support/SuffixTree.h
+++ b/llvm/include/llvm/Support/SuffixTree.h
@@ -145,7 +145,7 @@ public:
     unsigned Length;
 
     /// The start indices of each occurrence.
-    std::vector<unsigned> StartIndices;
+    SmallVector<unsigned> StartIndices;
   };
 
 private:
@@ -232,7 +232,7 @@ public:
   /// Construct a suffix tree from a sequence of unsigned integers.
   ///
   /// \param Str The string to construct the suffix tree for.
-  SuffixTree(const std::vector<unsigned> &Str);
+  SuffixTree(const ArrayRef<unsigned> &Str);
 
   /// Iterator for finding all repeated substrings in the suffix tree.
   struct RepeatedSubstringIterator {
@@ -244,7 +244,7 @@ public:
     RepeatedSubstring RS;
 
     /// The nodes left to visit.
-    std::vector<SuffixTreeNode *> ToVisit;
+    SmallVector<SuffixTreeNode *> ToVisit;
 
     /// The minimum length of a repeated substring to find.
     /// Since we're outlining, we want at least two instructions in the range.
@@ -260,7 +260,7 @@ public:
       N = nullptr;
 
       // Each leaf node represents a repeat of a string.
-      std::vector<SuffixTreeNode *> LeafChildren;
+      SmallVector<SuffixTreeNode *> LeafChildren;
 
       // Continue visiting nodes until we find one which repeats more than once.
       while (!ToVisit.empty()) {
diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index a7422f6f8d39..358a22f341eb 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -136,11 +136,11 @@ struct InstructionMapper {
   DenseMap<MachineBasicBlock *, unsigned> MBBFlagsMap;
 
   /// The vector of unsigned integers that the module is mapped to.
-  std::vector<unsigned> UnsignedVec;
+  SmallVector<unsigned> UnsignedVec;
 
   /// Stores the location of the instruction associated with the integer
   /// at index i in \p UnsignedVec for each index i.
-  std::vector<MachineBasicBlock::iterator> InstrList;
+  SmallVector<MachineBasicBlock::iterator> InstrList;
 
   // Set if we added an illegal number in the previous step.
   // Since each illegal number is unique, we only need one of them between
@@ -157,8 +157,8 @@ struct InstructionMapper {
   unsigned mapToLegalUnsigned(
       MachineBasicBlock::iterator &It, bool &CanOutlineWithPrevInstr,
       bool &HaveLegalRange, unsigned &NumLegalInBlock,
-      std::vector<unsigned> &UnsignedVecForMBB,
-      std::vector<MachineBasicBlock::iterator> &InstrListForMBB) {
+      SmallVector<unsigned> &UnsignedVecForMBB,
+      SmallVector<MachineBasicBlock::iterator> &InstrListForMBB) {
     // We added something legal, so we should unset the AddedLegalLastTime
     // flag.
     AddedIllegalLastTime = false;
@@ -211,8 +211,8 @@ struct InstructionMapper {
   /// \returns The integer that \p *It was mapped to.
   unsigned mapToIllegalUnsigned(
       MachineBasicBlock::iterator &It, bool &CanOutlineWithPrevInstr,
-      std::vector<unsigned> &UnsignedVecForMBB,
-      std::vector<MachineBasicBlock::iterator> &InstrListForMBB) {
+      SmallVector<unsigned> &UnsignedVecForMBB,
+      SmallVector<MachineBasicBlock::iterator> &InstrListForMBB) {
     // Can't outline an illegal instruction. Set the flag.
     CanOutlineWithPrevInstr = false;
 
@@ -287,8 +287,8 @@ struct InstructionMapper {
 
     // FIXME: Should this all just be handled in the target, rather than using
     // repeated calls to getOutliningType?
-    std::vector<unsigned> UnsignedVecForMBB;
-    std::vector<MachineBasicBlock::iterator> InstrListForMBB;
+    SmallVector<unsigned> UnsignedVecForMBB;
+    SmallVector<MachineBasicBlock::iterator> InstrListForMBB;
 
     LLVM_DEBUG(dbgs() << "*** Mapping outlinable ranges ***\n");
     for (auto &OutlinableRange : OutlinableRanges) {
diff --git a/llvm/lib/Support/SuffixTree.cpp b/llvm/lib/Support/SuffixTree.cpp
index 0d419f12cd1d..e2cd7b6073ac 100644
--- a/llvm/lib/Support/SuffixTree.cpp
+++ b/llvm/lib/Support/SuffixTree.cpp
@@ -16,7 +16,7 @@
 
 using namespace llvm;
 
-SuffixTree::SuffixTree(const std::vector<unsigned> &Str) : Str(Str) {
+SuffixTree::SuffixTree(const ArrayRef<unsigned> &Str) : Str(Str) {
   Root = insertInternalNode(nullptr, EmptyIdx, EmptyIdx, 0);
   Active.Node = Root;
 
@@ -70,7 +70,7 @@ SuffixTreeNode *SuffixTree::insertInternalNode(SuffixTreeNode *Parent,
 void SuffixTree::setSuffixIndices() {
   // List of nodes we need to visit along with the current length of the
   // string.
-  std::vector<std::pair<SuffixTreeNode *, unsigned>> ToVisit;
+  SmallVector<std::pair<SuffixTreeNode *, unsigned>> ToVisit;
 
   // Current node being visited.
   SuffixTreeNode *CurrNode = Root;