diff --git a/llvm/include/llvm/ProfileData/MemProf.h b/llvm/include/llvm/ProfileData/MemProf.h
index 0e6245acb77e8..0e4bb9cc3c6cb 100644
--- a/llvm/include/llvm/ProfileData/MemProf.h
+++ b/llvm/include/llvm/ProfileData/MemProf.h
@@ -440,7 +440,7 @@ struct IndexedMemProfRecord {
   void serialize(const MemProfSchema &Schema, raw_ostream &OS,
                  IndexedVersion Version,
                  llvm::DenseMap<memprof::CallStackId, LinearCallStackId>
-                     *MemProfCallStackIndexes = nullptr);
+                     *MemProfCallStackIndexes = nullptr) const;
 
   // Deserializes memprof records from the Buffer.
   static IndexedMemProfRecord deserialize(const MemProfSchema &Schema,
diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index 6a8f25d4d3bfb..d707c07e6dc50 100644
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -282,7 +282,7 @@ std::string getPGOFuncName(StringRef Name, GlobalValue::LinkageTypes Linkage,
 static StringRef stripDirPrefix(StringRef PathNameStr, uint32_t NumPrefix) {
   uint32_t Count = NumPrefix;
   uint32_t Pos = 0, LastPos = 0;
-  for (auto & CI : PathNameStr) {
+  for (const auto &CI : PathNameStr) {
     ++Pos;
     if (llvm::sys::path::is_separator(CI)) {
       LastPos = Pos;
@@ -1299,7 +1299,7 @@ void annotateValueSite(Module &M, Instruction &Inst,
 
   // Value Profile Data
   uint32_t MDCount = MaxMDCount;
-  for (auto &VD : VDs) {
+  for (const auto &VD : VDs) {
     Vals.push_back(MDHelper.createConstant(
         ConstantInt::get(Type::getInt64Ty(Ctx), VD.Value)));
     Vals.push_back(MDHelper.createConstant(
diff --git a/llvm/lib/ProfileData/InstrProfWriter.cpp b/llvm/lib/ProfileData/InstrProfWriter.cpp
index a73f72a534f16..7d7c980a9e11f 100644
--- a/llvm/lib/ProfileData/InstrProfWriter.cpp
+++ b/llvm/lib/ProfileData/InstrProfWriter.cpp
@@ -55,7 +55,7 @@ class ProfOStream {
   ProfOStream(raw_string_ostream &STR)
       : IsFDOStream(false), OS(STR), LE(STR, llvm::endianness::little) {}
 
-  uint64_t tell() { return OS.tell(); }
+  [[nodiscard]] uint64_t tell() const { return OS.tell(); }
   void write(uint64_t V) { LE.write<uint64_t>(V); }
   void write32(uint32_t V) { LE.write<uint32_t>(V); }
   void writeByte(uint8_t V) { LE.write<uint8_t>(V); }
@@ -894,7 +894,7 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
   BinaryIds.erase(std::unique(BinaryIds.begin(), BinaryIds.end()),
                   BinaryIds.end());
 
-  for (auto BI : BinaryIds) {
+  for (const auto &BI : BinaryIds) {
     // Increment by binary id length data type size.
     BinaryIdsSectionSize += sizeof(uint64_t);
     // Increment by binary id data length, aligned to 8 bytes.
@@ -903,7 +903,7 @@ Error InstrProfWriter::writeImpl(ProfOStream &OS) {
   // Write binary ids section size.
   OS.write(BinaryIdsSectionSize);
 
-  for (auto BI : BinaryIds) {
+  for (const auto &BI : BinaryIds) {
     uint64_t BILen = BI.size();
     // Write binary id length.
     OS.write(BILen);
diff --git a/llvm/lib/ProfileData/MemProf.cpp b/llvm/lib/ProfileData/MemProf.cpp
index aecac24169526..620e2e2d71a0f 100644
--- a/llvm/lib/ProfileData/MemProf.cpp
+++ b/llvm/lib/ProfileData/MemProf.cpp
@@ -194,7 +194,8 @@ static void serializeV3(
 
 void IndexedMemProfRecord::serialize(
     const MemProfSchema &Schema, raw_ostream &OS, IndexedVersion Version,
-    llvm::DenseMap<CallStackId, LinearCallStackId> *MemProfCallStackIndexes) {
+    llvm::DenseMap<CallStackId, LinearCallStackId> *MemProfCallStackIndexes)
+    const {
   switch (Version) {
   case Version0:
   case Version1:
diff --git a/llvm/lib/ProfileData/MemProfReader.cpp b/llvm/lib/ProfileData/MemProfReader.cpp
index 693897f874a29..de58cb6331860 100644
--- a/llvm/lib/ProfileData/MemProfReader.cpp
+++ b/llvm/lib/ProfileData/MemProfReader.cpp
@@ -67,7 +67,7 @@ Error checkBuffer(const MemoryBuffer &Buffer) {
   uint64_t TotalSize = 0;
   const char *Next = Buffer.getBufferStart();
   while (Next < Buffer.getBufferEnd()) {
-    auto *H = reinterpret_cast<const Header *>(Next);
+    const auto *H = reinterpret_cast<const Header *>(Next);
     if (H->Version != MEMPROF_RAW_VERSION) {
       return make_error<InstrProfError>(instrprof_error::unsupported_version);
     }
@@ -597,7 +597,7 @@ RawMemProfReader::peekBuildIds(MemoryBuffer *DataBuffer) {
                   llvm::SmallSet<std::string, 10>>
       BuildIds;
   while (Next < DataBuffer->getBufferEnd()) {
-    auto *Header = reinterpret_cast<const memprof::Header *>(Next);
+    const auto *Header = reinterpret_cast<const memprof::Header *>(Next);
 
     const llvm::SmallVector<SegmentEntry> Entries =
         readSegmentEntries(Next + Header->SegmentOffset);
@@ -615,7 +615,7 @@ Error RawMemProfReader::readRawProfile(
   const char *Next = DataBuffer->getBufferStart();
 
   while (Next < DataBuffer->getBufferEnd()) {
-    auto *Header = reinterpret_cast<const memprof::Header *>(Next);
+    const auto *Header = reinterpret_cast<const memprof::Header *>(Next);
 
     // Read in the segment information, check whether its the same across all
     // profiles in this binary file.