diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 42d342fe8769..773b70523fdc 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,12 @@
+2019-08-14  Bob Duff  <duff@adacore.com>
+
+	* sem_prag.adb (Validate_Compile_Time_Warning_Error): Attach the
+	warning to the Sloc of the first pragma argument, rather than to
+	the pragma itself. This is to make pragmas processed after the
+	back end use the same Sloc as pragmas processed earlier, in the
+	front end. There's no reason for this discrepancy, and it
+	hinders further work on this ticket.
+
 2019-08-14  Bob Duff  <duff@adacore.com>
 
 	* sem.ads (Inside_A_Generic): Remove the ??? comment.
diff --git a/gcc/ada/sem_prag.adb b/gcc/ada/sem_prag.adb
index 0f822bf02387..1db39f4a7f30 100644
--- a/gcc/ada/sem_prag.adb
+++ b/gcc/ada/sem_prag.adb
@@ -336,8 +336,8 @@ package body Sem_Prag is
    --  and alignment values performed by the back end.
 
    --  Note: the reason we store a Source_Ptr value instead of a Node_Id is
-   --  that by the time Validate_Unchecked_Conversions is called, Sprint will
-   --  already have modified all Sloc values if the -gnatD option is set.
+   --  that by the time Validate_Compile_Time_Warning_Errors is called, Sprint
+   --  will already have modified all Sloc values if the -gnatD option is set.
 
    type CTWE_Entry is record
       Eloc  : Source_Ptr;
@@ -32147,9 +32147,10 @@ package body Sem_Prag is
    -----------------------------------------
 
    procedure Validate_Compile_Time_Warning_Error (N : Node_Id) is
+      Arg1  : constant Node_Id := First (Pragma_Argument_Associations (N));
    begin
       Compile_Time_Warnings_Errors.Append
-        (New_Val => CTWE_Entry'(Eloc  => Sloc (N),
+        (New_Val => CTWE_Entry'(Eloc  => Sloc (Arg1),
                                 Scope => Current_Scope,
                                 Prag  => N));
    end Validate_Compile_Time_Warning_Error;