Index: usage.adb
===================================================================
--- usage.adb	(revision 247461)
+++ usage.adb	(working copy)
@@ -488,6 +488,7 @@
    Write_Line ("        e    treat all warnings (but not info) as errors");
    Write_Line ("        .e   turn on every optional info/warning " &
                                                   "(no exceptions)");
+   Write_Line ("        E    treat all run time warnings as errors");
    Write_Line ("        f+   turn on warnings for unreferenced formal");
    Write_Line ("        F*   turn off warnings for unreferenced formal");
    Write_Line ("        .f   turn on warnings for suspicious Subp'Access");
Index: warnsw.adb
===================================================================
--- warnsw.adb	(revision 247461)
+++ warnsw.adb	(working copy)
@@ -532,6 +532,9 @@
          when 'e' =>
             Warning_Mode                        := Treat_As_Error;
 
+         when 'E' =>
+            Warning_Mode                        := Treat_Run_Time_As_Error;
+
          when 'f' =>
             Check_Unreferenced_Formals          := True;
 
Index: errout.adb
===================================================================
--- errout.adb	(revision 247463)
+++ errout.adb	(working copy)
@@ -3097,6 +3097,17 @@
             --  '[' (will be/would have been raised at run time)
 
             when '[' =>
+
+               --  Switch the message from a warning to an error if the flag
+               --  -gnatwE is specified to treat run-time exception warnings
+               --  as errors.
+
+               if Is_Warning_Msg
+                 and then Warning_Mode = Treat_Run_Time_As_Error
+               then
+                  Is_Warning_Msg := False;
+               end if;
+
                if Is_Warning_Msg then
                   Set_Msg_Str ("will be raised at run time");
                else
Index: switch-b.adb
===================================================================
--- switch-b.adb	(revision 247461)
+++ switch-b.adb	(working copy)
@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 2001-2016, Free Software Foundation, Inc.         --
+--          Copyright (C) 2001-2017, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -490,6 +490,9 @@
                when 'e' =>
                   Warning_Mode := Treat_As_Error;
 
+               when 'E' =>
+                  Warning_Mode := Treat_Run_Time_As_Error;
+
                when 's' =>
                   Warning_Mode := Suppress;
 
Index: opt.ads
===================================================================
--- opt.ads	(revision 247475)
+++ opt.ads	(working copy)
@@ -1860,16 +1860,19 @@
    --  or where no warning has been suppressed by the use of the pragma.
    --  Modified by use of -gnatw.w/.W.
 
-   type Warning_Mode_Type is (Suppress, Normal, Treat_As_Error);
+   type Warning_Mode_Type is
+     (Suppress, Normal, Treat_As_Error, Treat_Run_Time_As_Error);
    Warning_Mode : Warning_Mode_Type := Normal;
    --  GNAT, GNATBIND
    --  Controls treatment of warning messages. If set to Suppress, warning
    --  messages are not generated at all. In Normal mode, they are generated
    --  but do not count as errors. In Treat_As_Error mode, warning messages are
-   --  generated and are treated as errors. Note that Warning_Mode = Suppress
-   --  causes pragma Warnings to be ignored (except for legality checks),
-   --  unless we are in GNATprove_Mode, which requires pragma Warnings to
-   --  be stored for the formal verification backend.
+   --  generated and are treated as errors. In Treat_Run_Time_As_Error, warning
+   --  messages regarding errors raised at run time are treated as errors. Note
+   --  that Warning_Mode = Suppress causes pragma Warnings to be ignored
+   --  (except for legality checks), unless we are in GNATprove_Mode, which
+   --  requires pragma Warnings to be stored for the formal verification
+   --  backend.
 
    Warnings_As_Errors_Count : Natural;
    --  GNAT