Index: clang/include/clang/Driver/Driver.h
===================================================================
--- clang/include/clang/Driver/Driver.h
+++ clang/include/clang/Driver/Driver.h
@@ -753,6 +753,9 @@
   /// Compute the default -fmodule-cache-path.
   /// \return True if the system provides a default cache directory.
   static bool getDefaultModuleCachePath(SmallVectorImpl<char> &Result);
+
+  /// Return the typical executable name for the specified driver \p Mode.
+  static const char *getExecutableForDriverMode(DriverMode Mode);
 };
 
 /// \return True if the last defined optimization level is -Ofast.
Index: clang/lib/Driver/Driver.cpp
===================================================================
--- clang/lib/Driver/Driver.cpp
+++ clang/lib/Driver/Driver.cpp
@@ -1064,79 +1064,55 @@
 bool Driver::loadDefaultConfigFiles(ArrayRef<StringRef> CfgFileSearchDirs) {
   if (CLOptions && CLOptions->hasArg(options::OPT_no_default_config))
     return false;
-  if (ClangNameParts.TargetPrefix.empty())
-    return false;
 
-  // If config file is not specified explicitly, try to deduce configuration
-  // from executable name. For instance, an executable 'armv7l-clang' will
-  // search for config file 'armv7l-clang.cfg'.
-  std::string CfgFileName =
-        ClangNameParts.TargetPrefix + '-' + ClangNameParts.ModeSuffix;
-
-  // Determine architecture part of the file name, if it is present.
-  StringRef CfgFileArch = CfgFileName;
-  size_t ArchPrefixLen = CfgFileArch.find('-');
-  if (ArchPrefixLen == StringRef::npos)
-    ArchPrefixLen = CfgFileArch.size();
-  llvm::Triple CfgTriple;
-  CfgFileArch = CfgFileArch.take_front(ArchPrefixLen);
-  CfgTriple = llvm::Triple(llvm::Triple::normalize(CfgFileArch));
-  if (CfgTriple.getArch() == llvm::Triple::ArchType::UnknownArch)
-    ArchPrefixLen = 0;
-
-  if (!StringRef(CfgFileName).endswith(".cfg"))
-    CfgFileName += ".cfg";
-
-  // If config file starts with architecture name and command line options
-  // redefine architecture (with options like -m32 -LE etc), try finding new
-  // config file with that architecture.
-  SmallString<128> FixedConfigFile;
-  size_t FixedArchPrefixLen = 0;
-  if (ArchPrefixLen) {
-    // Get architecture name from config file name like 'i386.cfg' or
-    // 'armv7l-clang.cfg'.
-    // Check if command line options changes effective triple.
-    llvm::Triple EffectiveTriple =
-        computeTargetTriple(*this, CfgTriple.getTriple(), *CLOptions);
-    if (CfgTriple.getArch() != EffectiveTriple.getArch()) {
-      FixedConfigFile = EffectiveTriple.getArchName();
-      FixedArchPrefixLen = FixedConfigFile.size();
-      // Append the rest of original file name so that file name transforms
-      // like: i386-clang.cfg -> x86_64-clang.cfg.
-      if (ArchPrefixLen < CfgFileName.size())
-        FixedConfigFile += CfgFileName.substr(ArchPrefixLen);
-    }
-  }
-
-  // Try to find config file. First try file with corrected architecture.
+  llvm::Triple RealTriple =
+      computeTargetTriple(*this, TargetTriple, *CLOptions);
+  assert(!RealTriple.str().empty());
+  StringRef RealMode = getExecutableForDriverMode(Mode);
+
+  // Search for config files in the following order:
+  // 1. <triple>-<mode>.cfg using real driver mode
+  //    (e.g. i386-pc-linux-gnu-clang++.cfg).
+  // 2. <triple>-<mode>.cfg using executable suffix
+  //    (e.g. i386-pc-linux-gnu-clang-g++.cfg).
+  // 3. <triple>.cfg + <mode>.cfg using real driver mode
+  //    (e.g. i386-pc-linux-gnu.cfg + clang++.cfg).
+  // 4. <triple>.cfg + <mode>.cfg using executable suffix
+  //    (e.g. i386-pc-linux-gnu.cfg + clang-g++.cfg).
+
+  // Try loading full config (variants 1. and 2.)
   llvm::SmallString<128> CfgFilePath;
-  if (!FixedConfigFile.empty()) {
-    if (searchForFile(CfgFilePath, CfgFileSearchDirs, FixedConfigFile,
-                      getVFS()))
-      return readConfigFile(CfgFilePath);
-    // If 'x86_64-clang.cfg' was not found, try 'x86_64.cfg'.
-    FixedConfigFile.resize(FixedArchPrefixLen);
-    FixedConfigFile.append(".cfg");
-    if (searchForFile(CfgFilePath, CfgFileSearchDirs, FixedConfigFile,
-                      getVFS()))
+  std::string CfgFileName = RealTriple.str() + '-' + RealMode.str() + ".cfg";
+  if (searchForFile(CfgFilePath, CfgFileSearchDirs, CfgFileName, getVFS()))
+    return readConfigFile(CfgFilePath);
+
+  bool ModeSuffixUnique = !ClangNameParts.ModeSuffix.empty() &&
+                          ClangNameParts.ModeSuffix != RealMode.str();
+  if (ModeSuffixUnique) {
+    CfgFileName = RealTriple.str() + '-' + ClangNameParts.ModeSuffix + ".cfg";
+    if (searchForFile(CfgFilePath, CfgFileSearchDirs, CfgFileName, getVFS()))
       return readConfigFile(CfgFilePath);
   }
 
-  // Then try original file name.
+  // Try loading separate config for the target (variants 3. and 4.)
+  CfgFileName = RealTriple.str() + ".cfg";
+  if (searchForFile(CfgFilePath, CfgFileSearchDirs, CfgFileName, getVFS()) &&
+      readConfigFile(CfgFilePath))
+    return true;
+
+  // Try loading separate config for the mode (second part of 3. and 4.)
+  CfgFileName = RealMode.str() + ".cfg";
   if (searchForFile(CfgFilePath, CfgFileSearchDirs, CfgFileName, getVFS()))
     return readConfigFile(CfgFilePath);
 
-  // Finally try removing driver mode part: 'x86_64-clang.cfg' -> 'x86_64.cfg'.
-  if (!ClangNameParts.ModeSuffix.empty() &&
-      !ClangNameParts.TargetPrefix.empty()) {
-    CfgFileName.assign(ClangNameParts.TargetPrefix);
-    CfgFileName.append(".cfg");
+  if (ModeSuffixUnique) {
+    CfgFileName = ClangNameParts.ModeSuffix + ".cfg";
     if (searchForFile(CfgFilePath, CfgFileSearchDirs, CfgFileName, getVFS()))
       return readConfigFile(CfgFilePath);
   }
 
   // If we were unable to find a config file deduced from executable name,
-  // do not report an error.
+  // that is not an error.
   return false;
 }
 
@@ -6197,6 +6173,26 @@
   return std::make_pair(IncludedFlagsBitmask, ExcludedFlagsBitmask);
 }
 
+const char *Driver::getExecutableForDriverMode(DriverMode Mode) {
+  switch (Mode) {
+  case GCCMode:
+    return "clang";
+  case GXXMode:
+    return "clang++";
+  case CPPMode:
+    return "clang-cpp";
+  case CLMode:
+    return "clang-cl";
+  case FlangMode:
+    return "flang";
+  case DXCMode:
+    return "clang-dxc";
+  }
+
+  assert(false && "Unhandled Mode");
+  return "clang";
+}
+
 bool clang::driver::isOptimizationLevelFast(const ArgList &Args) {
   return Args.hasFlag(options::OPT_Ofast, options::OPT_O_Group, false);
 }