Index: llvm/trunk/include/llvm/Support/FileSystem.h
===================================================================
--- llvm/trunk/include/llvm/Support/FileSystem.h
+++ llvm/trunk/include/llvm/Support/FileSystem.h
@@ -666,7 +666,15 @@
 /// @returns errc::success if the file times were successfully set, otherwise a
 ///          platform-specific error_code or errc::function_not_supported on
 ///          platforms where the functionality isn't available.
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time);
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime);
+
+/// Simpler version that sets both file modification and access time to the same
+/// time.
+inline std::error_code setLastAccessAndModificationTime(int FD,
+                                                        TimePoint<> Time) {
+  return setLastAccessAndModificationTime(FD, Time, Time);
+}
 
 /// Is status available?
 ///
Index: llvm/trunk/lib/Support/Unix/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc
+++ llvm/trunk/lib/Support/Unix/Path.inc
@@ -583,17 +583,22 @@
   return std::error_code();
 }
 
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime) {
 #if defined(HAVE_FUTIMENS)
   timespec Times[2];
-  Times[0] = Times[1] = sys::toTimeSpec(Time);
+  Times[0] = sys::toTimeSpec(AccessTime);
+  Times[1] = sys::toTimeSpec(ModificationTime);
   if (::futimens(FD, Times))
     return std::error_code(errno, std::generic_category());
   return std::error_code();
 #elif defined(HAVE_FUTIMES)
   timeval Times[2];
-  Times[0] = Times[1] = sys::toTimeVal(
-      std::chrono::time_point_cast<std::chrono::microseconds>(Time));
+  Times[0] = sys::toTimeVal(
+      std::chrono::time_point_cast<std::chrono::microseconds>(AccessTime));
+  Times[1] =
+      sys::toTimeVal(std::chrono::time_point_cast<std::chrono::microseconds>(
+          ModificationTime));
   if (::futimes(FD, Times))
     return std::error_code(errno, std::generic_category());
   return std::error_code();
Index: llvm/trunk/lib/Support/Windows/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Windows/Path.inc
+++ llvm/trunk/lib/Support/Windows/Path.inc
@@ -766,10 +766,12 @@
   return std::error_code();
 }
 
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
-  FILETIME FT = toFILETIME(Time);
+std::error_code setLastAccessAndModificationTime(int FD, TimePoint<> AccessTime,
+                                                 TimePoint<> ModificationTime) {
+  FILETIME AccessFT = toFILETIME(AccessTime);
+  FILETIME ModifyFT = toFILETIME(ModificationTime);
   HANDLE FileHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
-  if (!SetFileTime(FileHandle, NULL, &FT, &FT))
+  if (!SetFileTime(FileHandle, NULL, &AccessFT, &ModifyFT))
     return mapWindowsError(::GetLastError());
   return std::error_code();
 }
Index: llvm/trunk/tools/llvm-ar/llvm-ar.cpp
===================================================================
--- llvm/trunk/tools/llvm-ar/llvm-ar.cpp
+++ llvm/trunk/tools/llvm-ar/llvm-ar.cpp
@@ -410,7 +410,7 @@
     auto ModTimeOrErr = C.getLastModified();
     failIfError(ModTimeOrErr.takeError());
     failIfError(
-        sys::fs::setLastModificationAndAccessTime(FD, ModTimeOrErr.get()));
+        sys::fs::setLastAccessAndModificationTime(FD, ModTimeOrErr.get()));
   }
 
   if (close(FD))
Index: llvm/trunk/unittests/Support/Path.cpp
===================================================================
--- llvm/trunk/unittests/Support/Path.cpp
+++ llvm/trunk/unittests/Support/Path.cpp
@@ -1297,7 +1297,7 @@
   ASSERT_NO_ERROR(sys::fs::openFileForWrite(Twine(TempPath), FileDescriptor,
                                             fs::CD_OpenExisting));
   TimePoint<> Epoch(std::chrono::milliseconds(0));
-  ASSERT_NO_ERROR(fs::setLastModificationAndAccessTime(FileDescriptor, Epoch));
+  ASSERT_NO_ERROR(fs::setLastAccessAndModificationTime(FileDescriptor, Epoch));
   ::close(FileDescriptor);
 
   // Open the file and ensure access time is updated, when forced.