Index: include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- include/clang/Basic/DiagnosticDriverKinds.td
+++ include/clang/Basic/DiagnosticDriverKinds.td
@@ -230,6 +230,8 @@
   "The last /TC or /TP option takes precedence over earlier instances">;
 def note_drv_address_sanitizer_debug_runtime : Note<
   "AddressSanitizer doesn't support linking with debug runtime libraries yet">;
+def note_drv_supported_values : Note<"supported values are:">;
+def note_drv_supported_value_with_description : Note<"'%0' for standard '%1'">;
 
 def err_analyzer_config_no_value : Error<
   "analyzer-config option '%0' has a key but no value">;
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1694,10 +1694,21 @@
       .Case(alias, LangStandard::lang_##id)
 #include "clang/Frontend/LangStandards.def"
       .Default(LangStandard::lang_unspecified);
-    if (LangStd == LangStandard::lang_unspecified)
+    if (LangStd == LangStandard::lang_unspecified) {
       Diags.Report(diag::err_drv_invalid_value)
         << A->getAsString(Args) << A->getValue();
-    else {
+      // Report all supported standards with description.
+      Diags.Report(diag::note_drv_supported_values);
+      for (unsigned KindValue = 0;
+          KindValue != LangStandard::lang_unspecified;
+          ++KindValue)
+      {
+        const LangStandard &Std = LangStandard::getLangStandardForKind(
+          static_cast<LangStandard::Kind>(KindValue));
+        Diags.Report(diag::note_drv_supported_value_with_description)
+          << Std.getName() << Std.getDescription();
+      }
+    } else {
       // Valid standard, check to make sure language and standard are
       // compatible.
       const LangStandard &Std = LangStandard::getLangStandardForKind(LangStd);
Index: test/Driver/unknown-std.c
===================================================================
--- /dev/null
+++ test/Driver/unknown-std.c
@@ -0,0 +1,42 @@
+// RUN: not %clang %s -std=foobar -c 2>&1 | \
+// RUN: FileCheck %s
+
+// CHECK: error: invalid value 'foobar' in '-std=foobar'
+// CHECK: note: supported values are:
+// CHECK: note: 'c89' for standard 'ISO C 1990'
+// CHECK: note: 'c90' for standard 'ISO C 1990'
+// CHECK: note: 'iso9899:1990' for standard 'ISO C 1990'
+// CHECK: note: 'iso9899:199409' for standard 'ISO C 1990 with amendment 1'
+// CHECK: note: 'gnu89' for standard 'ISO C 1990 with GNU extensions'
+// CHECK: note: 'gnu90' for standard 'ISO C 1990 with GNU extensions'
+// CHECK: note: 'c99' for standard 'ISO C 1999'
+// CHECK: note: 'c9x' for standard 'ISO C 1999'
+// CHECK: note: 'iso9899:1999' for standard 'ISO C 1999'
+// CHECK: note: 'iso9899:199x' for standard 'ISO C 1999'
+// CHECK: note: 'gnu99' for standard 'ISO C 1999 with GNU extensions'
+// CHECK: note: 'gnu9x' for standard 'ISO C 1999 with GNU extensions'
+// CHECK: note: 'c11' for standard 'ISO C 2011'
+// CHECK: note: 'c1x' for standard 'ISO C 2011'
+// CHECK: note: 'iso9899:2011' for standard 'ISO C 2011'
+// CHECK: note: 'iso9899:201x' for standard 'ISO C 2011'
+// CHECK: note: 'gnu11' for standard 'ISO C 2011 with GNU extensions'
+// CHECK: note: 'gnu1x' for standard 'ISO C 2011 with GNU extensions'
+// CHECK: note: 'c++98' for standard 'ISO C++ 1998 with amendments'
+// CHECK: note: 'c++03' for standard 'ISO C++ 1998 with amendments'
+// CHECK: note: 'gnu++98' for standard 'ISO C++ 1998 with amendments and GNU extensions'
+// CHECK: note: 'c++0x' for standard 'ISO C++ 2011 with amendments'
+// CHECK: note: 'c++11' for standard 'ISO C++ 2011 with amendments'
+// CHECK: note: 'gnu++0x' for standard 'ISO C++ 2011 with amendments and GNU extensions'
+// CHECK: note: 'gnu++11' for standard 'ISO C++ 2011 with amendments and GNU extensions'
+// CHECK: note: 'c++1y' for standard 'ISO C++ 2014 with amendments'
+// CHECK: note: 'c++14' for standard 'ISO C++ 2014 with amendments'
+// CHECK: note: 'gnu++1y' for standard 'ISO C++ 2014 with amendments and GNU extensions'
+// CHECK: note: 'gnu++14' for standard 'ISO C++ 2014 with amendments and GNU extensions'
+// CHECK: note: 'c++1z' for standard 'Working draft for ISO C++ 2017'
+// CHECK: note: 'gnu++1z' for standard 'Working draft for ISO C++ 2017 with GNU extensions'
+// CHECK: note: 'cl' for standard 'OpenCL 1.0'
+// CHECK: note: 'cl1.1' for standard 'OpenCL 1.1'
+// CHECK: note: 'cl1.2' for standard 'OpenCL 1.2'
+// CHECK: note: 'cl2.0' for standard 'OpenCL 2.0'
+// CHECK: note: 'cuda' for standard 'NVIDIA CUDA(tm)'
+