diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index 98b30e084b18b..8f095649f87ce 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -972,7 +972,7 @@ void PGOHash::combine(HashType Type) {
   if (Count && Count % NumTypesPerWord == 0) {
     using namespace llvm::support;
     uint64_t Swapped =
-        endian::byte_swap<uint64_t, llvm::endianness::little>(Working);
+        endian::byte_swap<uint64_t>(Working, llvm::endianness::little);
     MD5.update(llvm::ArrayRef((uint8_t *)&Swapped, sizeof(Swapped)));
     Working = 0;
   }
@@ -999,7 +999,7 @@ uint64_t PGOHash::finalize() {
     } else {
       using namespace llvm::support;
       uint64_t Swapped =
-          endian::byte_swap<uint64_t, llvm::endianness::little>(Working);
+          endian::byte_swap<uint64_t>(Working, llvm::endianness::little);
       MD5.update(llvm::ArrayRef((uint8_t *)&Swapped, sizeof(Swapped)));
     }
   }
diff --git a/llvm/include/llvm/Bitstream/BitstreamWriter.h b/llvm/include/llvm/Bitstream/BitstreamWriter.h
index 5f53681320ce4..a2938642f824a 100644
--- a/llvm/include/llvm/Bitstream/BitstreamWriter.h
+++ b/llvm/include/llvm/Bitstream/BitstreamWriter.h
@@ -87,7 +87,7 @@ class BitstreamWriter {
 
   void WriteWord(unsigned Value) {
     Value =
-        support::endian::byte_swap<uint32_t, llvm::endianness::little>(Value);
+        support::endian::byte_swap<uint32_t>(Value, llvm::endianness::little);
     Buffer.append(reinterpret_cast<const char *>(&Value),
                   reinterpret_cast<const char *>(&Value + 1));
   }
diff --git a/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h b/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
index 7d1a85ba528fc..e09958160b9a0 100644
--- a/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
+++ b/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h
@@ -1215,19 +1215,19 @@ namespace accessors {
 /// Return the structural hash associated with the function.
 template <class FuncRecordTy, llvm::endianness Endian>
 uint64_t getFuncHash(const FuncRecordTy *Record) {
-  return support::endian::byte_swap<uint64_t, Endian>(Record->FuncHash);
+  return support::endian::byte_swap<uint64_t>(Record->FuncHash, Endian);
 }
 
 /// Return the coverage map data size for the function.
 template <class FuncRecordTy, llvm::endianness Endian>
 uint64_t getDataSize(const FuncRecordTy *Record) {
-  return support::endian::byte_swap<uint32_t, Endian>(Record->DataSize);
+  return support::endian::byte_swap<uint32_t>(Record->DataSize, Endian);
 }
 
 /// Return the function lookup key. The value is considered opaque.
 template <class FuncRecordTy, llvm::endianness Endian>
 uint64_t getFuncNameRef(const FuncRecordTy *Record) {
-  return support::endian::byte_swap<uint64_t, Endian>(Record->NameRef);
+  return support::endian::byte_swap<uint64_t>(Record->NameRef, Endian);
 }
 
 /// Return the PGO name of the function. Used for formats in which the name is
@@ -1280,14 +1280,14 @@ struct CovMapFunctionRecordV1 {
 
   /// Return function lookup key. The value is consider opaque.
   template <llvm::endianness Endian> IntPtrT getFuncNameRef() const {
-    return support::endian::byte_swap<IntPtrT, Endian>(NamePtr);
+    return support::endian::byte_swap<IntPtrT>(NamePtr, Endian);
   }
 
   /// Return the PGO name of the function.
   template <llvm::endianness Endian>
   Error getFuncName(InstrProfSymtab &ProfileNames, StringRef &FuncName) const {
     IntPtrT NameRef = getFuncNameRef<Endian>();
-    uint32_t NameS = support::endian::byte_swap<uint32_t, Endian>(NameSize);
+    uint32_t NameS = support::endian::byte_swap<uint32_t>(NameSize, Endian);
     FuncName = ProfileNames.getFuncName(NameRef, NameS);
     if (NameS && FuncName.empty())
       return make_error<CoverageMapError>(coveragemap_error::malformed,
@@ -1385,7 +1385,7 @@ struct CovMapFunctionRecordV3 {
 
   /// Get the filename set reference.
   template <llvm::endianness Endian> uint64_t getFilenamesRef() const {
-    return support::endian::byte_swap<uint64_t, Endian>(FilenamesRef);
+    return support::endian::byte_swap<uint64_t>(FilenamesRef, Endian);
   }
 
   /// Read the inline coverage mapping. Ignore the buffer parameter, it is for
@@ -1416,19 +1416,19 @@ struct CovMapHeader {
 #define COVMAP_HEADER(Type, LLVMType, Name, Init) Type Name;
 #include "llvm/ProfileData/InstrProfData.inc"
   template <llvm::endianness Endian> uint32_t getNRecords() const {
-    return support::endian::byte_swap<uint32_t, Endian>(NRecords);
+    return support::endian::byte_swap<uint32_t>(NRecords, Endian);
   }
 
   template <llvm::endianness Endian> uint32_t getFilenamesSize() const {
-    return support::endian::byte_swap<uint32_t, Endian>(FilenamesSize);
+    return support::endian::byte_swap<uint32_t>(FilenamesSize, Endian);
   }
 
   template <llvm::endianness Endian> uint32_t getCoverageSize() const {
-    return support::endian::byte_swap<uint32_t, Endian>(CoverageSize);
+    return support::endian::byte_swap<uint32_t>(CoverageSize, Endian);
   }
 
   template <llvm::endianness Endian> uint32_t getVersion() const {
-    return support::endian::byte_swap<uint32_t, Endian>(Version);
+    return support::endian::byte_swap<uint32_t>(Version, Endian);
   }
 };
 
diff --git a/llvm/include/llvm/Support/Endian.h b/llvm/include/llvm/Support/Endian.h
index 6c86feb78053c..51db225841dbe 100644
--- a/llvm/include/llvm/Support/Endian.h
+++ b/llvm/include/llvm/Support/Endian.h
@@ -49,7 +49,9 @@ template <typename value_type>
 
 /// Swap the bytes of value to match the given endianness.
 template <typename value_type, endianness endian>
-[[nodiscard]] inline value_type byte_swap(value_type value) {
+[[nodiscard]]
+LLVM_DEPRECATED("Pass endian as a function argument instead",
+                "byte_swap") inline value_type byte_swap(value_type value) {
   return byte_swap(value, endian);
 }
 
@@ -137,8 +139,8 @@ template <typename value_type, endianness endian, std::size_t alignment>
            LLVM_ASSUME_ALIGNED(
                memory, (detail::PickAlignment<value_type, alignment>::value)),
            sizeof(value_type) * 2);
-    val[0] = byte_swap<value_type, endian>(val[0]);
-    val[1] = byte_swap<value_type, endian>(val[1]);
+    val[0] = byte_swap<value_type>(val[0], endian);
+    val[1] = byte_swap<value_type>(val[1], endian);
 
     // Shift bits from the lower value into place.
     make_unsigned_t<value_type> lowerVal = val[0] >> startBit;
@@ -172,8 +174,8 @@ inline void writeAtBitAlignment(void *memory, value_type value,
            LLVM_ASSUME_ALIGNED(
                memory, (detail::PickAlignment<value_type, alignment>::value)),
            sizeof(value_type) * 2);
-    val[0] = byte_swap<value_type, endian>(val[0]);
-    val[1] = byte_swap<value_type, endian>(val[1]);
+    val[0] = byte_swap<value_type>(val[0], endian);
+    val[1] = byte_swap<value_type>(val[1], endian);
 
     // Mask off any existing bits in the upper part of the lower value that
     // we want to replace.
@@ -201,8 +203,8 @@ inline void writeAtBitAlignment(void *memory, value_type value,
     val[1] |= upperVal;
 
     // Finally, rewrite values.
-    val[0] = byte_swap<value_type, endian>(val[0]);
-    val[1] = byte_swap<value_type, endian>(val[1]);
+    val[0] = byte_swap<value_type>(val[0], endian);
+    val[1] = byte_swap<value_type>(val[1], endian);
     memcpy(LLVM_ASSUME_ALIGNED(
                memory, (detail::PickAlignment<value_type, alignment>::value)),
            &val[0], sizeof(value_type) * 2);
diff --git a/llvm/lib/CGData/CodeGenDataWriter.cpp b/llvm/lib/CGData/CodeGenDataWriter.cpp
index 14a8558ba63b7..a2bbceebd0317 100644
--- a/llvm/lib/CGData/CodeGenDataWriter.cpp
+++ b/llvm/lib/CGData/CodeGenDataWriter.cpp
@@ -40,7 +40,7 @@ void CGDataOStream::patch(ArrayRef<CGDataPatchItem> P) {
     for (const auto &K : P) {
       for (size_t I = 0; I < K.D.size(); ++I) {
         uint64_t Bytes =
-            endian::byte_swap<uint64_t, llvm::endianness::little>(K.D[I]);
+            endian::byte_swap<uint64_t>(K.D[I], llvm::endianness::little);
         Data.replace(K.Pos + I * sizeof(uint64_t), sizeof(uint64_t),
                      reinterpret_cast<const char *>(&Bytes), sizeof(uint64_t));
       }
@@ -52,7 +52,7 @@ void CGDataOStream::patch(ArrayRef<CGDataPatchItem> P) {
     for (const auto &K : P) {
       for (size_t I = 0; I < K.D.size(); ++I) {
         uint64_t Bytes =
-            endian::byte_swap<uint64_t, llvm::endianness::little>(K.D[I]);
+            endian::byte_swap<uint64_t>(K.D[I], llvm::endianness::little);
         VOStream.pwrite(reinterpret_cast<const char *>(&Bytes),
                         sizeof(uint64_t), K.Pos + I * sizeof(uint64_t));
       }
diff --git a/llvm/lib/MC/DXContainerRootSignature.cpp b/llvm/lib/MC/DXContainerRootSignature.cpp
index 2338370d84389..713aa3d8143e8 100644
--- a/llvm/lib/MC/DXContainerRootSignature.cpp
+++ b/llvm/lib/MC/DXContainerRootSignature.cpp
@@ -23,9 +23,8 @@ static uint32_t writePlaceholder(raw_svector_ostream &Stream) {
 static uint32_t rewriteOffsetToCurrentByte(raw_svector_ostream &Stream,
                                            uint32_t Offset) {
   uint32_t ByteOffset = Stream.tell();
-  uint32_t Value =
-      support::endian::byte_swap<uint32_t, llvm::endianness::little>(
-          ByteOffset);
+  uint32_t Value = support::endian::byte_swap<uint32_t>(
+      ByteOffset, llvm::endianness::little);
   Stream.pwrite(reinterpret_cast<const char *>(&Value), sizeof(Value), Offset);
   return ByteOffset;
 }
diff --git a/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp b/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
index fc2577e6ada5d..075ad8d7aec8b 100644
--- a/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp
@@ -949,9 +949,9 @@ loadTestingFormat(StringRef Data, StringRef CompilationDir) {
   if (Data.size() < sizeof(uint64_t))
     return make_error<CoverageMapError>(coveragemap_error::malformed,
                                         "the size of data is too small");
-  auto TestingVersion =
-      support::endian::byte_swap<uint64_t, llvm::endianness::little>(
-          *reinterpret_cast<const uint64_t *>(Data.data()));
+  auto TestingVersion = support::endian::byte_swap<uint64_t>(
+      *reinterpret_cast<const uint64_t *>(Data.data()),
+      llvm::endianness::little);
   Data = Data.substr(sizeof(uint64_t));
 
   // Read the ProfileNames data.
@@ -1274,9 +1274,9 @@ BinaryCoverageReader::create(
   std::vector<std::unique_ptr<BinaryCoverageReader>> Readers;
 
   if (ObjectBuffer.getBuffer().size() > sizeof(TestingFormatMagic)) {
-    uint64_t Magic =
-        support::endian::byte_swap<uint64_t, llvm::endianness::little>(
-            *reinterpret_cast<const uint64_t *>(ObjectBuffer.getBufferStart()));
+    uint64_t Magic = support::endian::byte_swap<uint64_t>(
+        *reinterpret_cast<const uint64_t *>(ObjectBuffer.getBufferStart()),
+        llvm::endianness::little);
     if (Magic == TestingFormatMagic) {
       // This is a special format used for testing.
       auto ReaderOrErr =
diff --git a/llvm/lib/ProfileData/Coverage/CoverageMappingWriter.cpp b/llvm/lib/ProfileData/Coverage/CoverageMappingWriter.cpp
index 12b1687af69db..3875f01c48528 100644
--- a/llvm/lib/ProfileData/Coverage/CoverageMappingWriter.cpp
+++ b/llvm/lib/ProfileData/Coverage/CoverageMappingWriter.cpp
@@ -292,7 +292,7 @@ void CoverageMappingWriter::write(raw_ostream &OS) {
 
 void TestingFormatWriter::write(raw_ostream &OS, TestingFormatVersion Version) {
   auto ByteSwap = [](uint64_t N) {
-    return support::endian::byte_swap<uint64_t, llvm::endianness::little>(N);
+    return support::endian::byte_swap<uint64_t>(N, llvm::endianness::little);
   };
 
   // Output a 64bit magic number.
diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index e1c6315853b3b..3c8e44a18f533 100644
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -292,7 +292,7 @@ void ProfOStream::patch(ArrayRef<PatchItem> P) {
     for (const auto &K : P) {
       for (int I = 0, E = K.D.size(); I != E; I++) {
         uint64_t Bytes =
-            endian::byte_swap<uint64_t, llvm::endianness::little>(K.D[I]);
+            endian::byte_swap<uint64_t>(K.D[I], llvm::endianness::little);
         Data.replace(K.Pos + I * sizeof(uint64_t), sizeof(uint64_t),
                      (const char *)&Bytes, sizeof(uint64_t));
       }
diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index 1da92eafa4b4a..d2ae4b5226ff6 100644
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -1186,10 +1186,10 @@ IndexedInstrProfReader::readSummary(IndexedInstrProf::ProfVersion Version,
   if (Version >= IndexedInstrProf::Version4) {
     const IndexedInstrProf::Summary *SummaryInLE =
         reinterpret_cast<const IndexedInstrProf::Summary *>(Cur);
-    uint64_t NFields = endian::byte_swap<uint64_t, llvm::endianness::little>(
-        SummaryInLE->NumSummaryFields);
-    uint64_t NEntries = endian::byte_swap<uint64_t, llvm::endianness::little>(
-        SummaryInLE->NumCutoffEntries);
+    uint64_t NFields = endian::byte_swap<uint64_t>(
+        SummaryInLE->NumSummaryFields, llvm::endianness::little);
+    uint64_t NEntries = endian::byte_swap<uint64_t>(
+        SummaryInLE->NumCutoffEntries, llvm::endianness::little);
     uint32_t SummarySize =
         IndexedInstrProf::Summary::getSize(NFields, NEntries);
     std::unique_ptr<IndexedInstrProf::Summary> SummaryData =
@@ -1198,7 +1198,7 @@ IndexedInstrProfReader::readSummary(IndexedInstrProf::ProfVersion Version,
     const uint64_t *Src = reinterpret_cast<const uint64_t *>(SummaryInLE);
     uint64_t *Dst = reinterpret_cast<uint64_t *>(SummaryData.get());
     for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
-      Dst[I] = endian::byte_swap<uint64_t, llvm::endianness::little>(Src[I]);
+      Dst[I] = endian::byte_swap<uint64_t>(Src[I], llvm::endianness::little);
 
     SummaryEntryVector DetailedSummary;
     for (unsigned I = 0; I < SummaryData->NumCutoffEntries; I++) {
diff --git a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
index 31bf6a9d2d9c8..e09ddb45da6e9 100644
--- a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
+++ b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
@@ -1519,10 +1519,10 @@ class MemoryMatcher {
 
 static StringRef detectStubKind(const Session::MemoryRegionInfo &Stub) {
   using namespace support::endian;
-  auto Armv7MovWTle = byte_swap<uint32_t, endianness::little>(0xe300c000);
-  auto Armv7BxR12le = byte_swap<uint32_t, endianness::little>(0xe12fff1c);
-  auto Thumbv7MovWTle = byte_swap<uint32_t, endianness::little>(0x0c00f240);
-  auto Thumbv7BxR12le = byte_swap<uint16_t, endianness::little>(0x4760);
+  auto Armv7MovWTle = byte_swap<uint32_t>(0xe300c000, endianness::little);
+  auto Armv7BxR12le = byte_swap<uint32_t>(0xe12fff1c, endianness::little);
+  auto Thumbv7MovWTle = byte_swap<uint32_t>(0x0c00f240, endianness::little);
+  auto Thumbv7BxR12le = byte_swap<uint16_t>(0x4760, endianness::little);
 
   MemoryMatcher M(Stub.getContent());
   if (M.matchMask(Thumbv7MovWTle)) {
diff --git a/llvm/unittests/MC/StringTableBuilderTest.cpp b/llvm/unittests/MC/StringTableBuilderTest.cpp
index 05f469a229bf9..44a985be6cfcb 100644
--- a/llvm/unittests/MC/StringTableBuilderTest.cpp
+++ b/llvm/unittests/MC/StringTableBuilderTest.cpp
@@ -58,8 +58,8 @@ TEST(StringTableBuilderTest, BasicWinCOFF) {
 
   std::string Expected;
 
-  ExpectedSize = support::endian::byte_swap<uint32_t, llvm::endianness::little>(
-      ExpectedSize);
+  ExpectedSize = support::endian::byte_swap<uint32_t>(ExpectedSize,
+                                                      llvm::endianness::little);
   Expected.append((const char*)&ExpectedSize, 4);
   Expected += "pygmy hippopotamus";
   Expected += '\x00';