diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -2600,6 +2600,10 @@
   if (std::error_code EC = FS->makeAbsolute(Path))
     return make_string_error(EC.message());
 
+  llvm::SmallVector<std::string, 2> FilesToLookFor;
+  FilesToLookFor.push_back(".clang-format");
+  FilesToLookFor.push_back("_clang-format");
+
   for (StringRef Directory = Path; !Directory.empty();
        Directory = llvm::sys::path::parent_path(Directory)) {
 
@@ -2609,43 +2613,35 @@
       continue;
     }
 
-    SmallString<128> ConfigFile(Directory);
-
-    llvm::sys::path::append(ConfigFile, ".clang-format");
-    LLVM_DEBUG(llvm::dbgs() << "Trying " << ConfigFile << "...\n");
+    for (const auto &F : FilesToLookFor) {
+      SmallString<128> ConfigFile(Directory);
 
-    Status = FS->status(ConfigFile.str());
-    bool FoundConfigFile =
-        Status && (Status->getType() == llvm::sys::fs::file_type::regular_file);
-    if (!FoundConfigFile) {
-      // Try _clang-format too, since dotfiles are not commonly used on Windows.
-      ConfigFile = Directory;
-      llvm::sys::path::append(ConfigFile, "_clang-format");
+      llvm::sys::path::append(ConfigFile, F);
       LLVM_DEBUG(llvm::dbgs() << "Trying " << ConfigFile << "...\n");
+
       Status = FS->status(ConfigFile.str());
-      FoundConfigFile = Status && (Status->getType() ==
-                                   llvm::sys::fs::file_type::regular_file);
-    }
 
-    if (FoundConfigFile) {
-      llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Text =
-          FS->getBufferForFile(ConfigFile.str());
-      if (std::error_code EC = Text.getError())
-        return make_string_error(EC.message());
-      if (std::error_code ec =
-              parseConfiguration(Text.get()->getBuffer(), &Style)) {
-        if (ec == ParseError::Unsuitable) {
-          if (!UnsuitableConfigFiles.empty())
-            UnsuitableConfigFiles.append(", ");
-          UnsuitableConfigFiles.append(ConfigFile);
-          continue;
+      if (Status &&
+          (Status->getType() == llvm::sys::fs::file_type::regular_file)) {
+        llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Text =
+            FS->getBufferForFile(ConfigFile.str());
+        if (std::error_code EC = Text.getError())
+          return make_string_error(EC.message());
+        if (std::error_code ec =
+                parseConfiguration(Text.get()->getBuffer(), &Style)) {
+          if (ec == ParseError::Unsuitable) {
+            if (!UnsuitableConfigFiles.empty())
+              UnsuitableConfigFiles.append(", ");
+            UnsuitableConfigFiles.append(ConfigFile);
+            continue;
+          }
+          return make_string_error("Error reading " + ConfigFile + ": " +
+                                   ec.message());
         }
-        return make_string_error("Error reading " + ConfigFile + ": " +
-                                 ec.message());
+        LLVM_DEBUG(llvm::dbgs()
+                   << "Using configuration file " << ConfigFile << "\n");
+        return Style;
       }
-      LLVM_DEBUG(llvm::dbgs()
-                 << "Using configuration file " << ConfigFile << "\n");
-      return Style;
     }
   }
   if (!UnsuitableConfigFiles.empty())