diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index be907d9..9fabcdf 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1071,6 +1071,26 @@
           llvm::sys::Process::StandardErrHasColors());
 }
 
+static bool checkVerifyPrefixes(const std::vector<std::string> &VerifyPrefixes,
+                                DiagnosticsEngine *Diags) {
+  bool Success = true;
+  for (const auto &Prefix : VerifyPrefixes) {
+    // Every prefix must start with a letter and contain only alphanumeric
+    // characters, hyphens, and underscores.
+    auto BadChar = std::find_if(Prefix.begin(), Prefix.end(),
+                                [](char C){return !isAlphanumeric(C)
+                                                  && C != '-' && C != '_';});
+    if (BadChar != Prefix.end() || !isLetter(Prefix[0])) {
+      Success = false;
+      if (Diags) {
+        Diags->Report(diag::err_drv_invalid_value) << "-verify=" << Prefix;
+        Diags->Report(diag::note_drv_verify_prefix_spelling);
+      }
+    }
+  }
+  return Success;
+}
+
 bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
                                 DiagnosticsEngine *Diags,
                                 bool DefaultDiagColor, bool DefaultShowOpt) {
@@ -1158,7 +1178,18 @@
   Opts.ShowSourceRanges = Args.hasArg(OPT_fdiagnostics_print_source_range_info);
   Opts.ShowParseableFixits = Args.hasArg(OPT_fdiagnostics_parseable_fixits);
   Opts.ShowPresumedLoc = !Args.hasArg(OPT_fno_diagnostics_use_presumed_location);
-  Opts.VerifyDiagnostics = Args.hasArg(OPT_verify);
+  Opts.VerifyDiagnostics = Args.hasArg(OPT_verify) || Args.hasArg(OPT_verify_EQ);
+  Opts.VerifyPrefixes = Args.getAllArgValues(OPT_verify_EQ);
+  if (Args.hasArg(OPT_verify))
+    Opts.VerifyPrefixes.push_back("expected");
+  // Keep VerifyPrefixes in its original order for the sake of diagnostics, and
+  // then sort it to prepare for fast lookup using std::binary_search.
+  if (!checkVerifyPrefixes(Opts.VerifyPrefixes, Diags)) {
+    Opts.VerifyDiagnostics = false;
+    Success = false;
+  }
+  else
+    std::sort(Opts.VerifyPrefixes.begin(), Opts.VerifyPrefixes.end());
   DiagnosticLevelMask DiagMask = DiagnosticLevelMask::None;
   Success &= parseDiagnosticLevelMask("-verify-ignore-unexpected=",
     Args.getAllArgValues(OPT_verify_ignore_unexpected_EQ),