[Ada] Remove repeated conversions between Source_Ptr and Int

[Pierre-Marie de Rodat via Gcc-patches]

Both Source_Ptr and Int are integer types (and even happen to have equal
ranges). Their values can be calculated without converting
back-and-forth, e.g.:

  Int (Loc1) - Int (Loc2)

can be written simply as:

  Int (Loc1 - Loc2)

Code cleanup related to handling of references to unset objects.
Offending occurrences found with various invocations of grep.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * par-ch10.adb, scng.adb, sem_res.adb, sinfo-utils.adb,
        treepr.adb: Simplify calculations with Source_Ptr and Loc
        values.
diff --git a/gcc/ada/par-ch10.adb b/gcc/ada/par-ch10.adb
--- a/gcc/ada/par-ch10.adb
+++ b/gcc/ada/par-ch10.adb
@@ -1194,7 +1194,7 @@ package body Ch10 is
       Write_Int (Int (Line));
 
       Write_Str (", file offset ");
-      Write_Int (Int (Loc) - Int (Source_First (Sind)));
+      Write_Int (Int (Loc - Source_First (Sind)));
    end Unit_Location;
 
 end Ch10;


diff --git a/gcc/ada/scng.adb b/gcc/ada/scng.adb
--- a/gcc/ada/scng.adb
+++ b/gcc/ada/scng.adb
@@ -130,11 +130,7 @@ package body Scng is
 
    procedure Check_End_Of_Line is
       Len : constant Int :=
-              Int (Scan_Ptr) -
-                Int (Current_Line_Start) -
-                  Wide_Char_Byte_Count;
-
-   --  Start of processing for Check_End_Of_Line
+              Int (Scan_Ptr - Current_Line_Start) - Wide_Char_Byte_Count;
 
    begin
       if Style_Check then


diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -11754,7 +11754,7 @@ package body Sem_Res is
 
                   Error_Msg
                     ("literal out of range of type Standard.Character",
-                     Source_Ptr (Int (Loc) + J));
+                     Loc + Source_Ptr (J));
                   return;
                end if;
             end loop;
@@ -11783,7 +11783,7 @@ package body Sem_Res is
 
                   Error_Msg
                     ("literal out of range of type Standard.Wide_Character",
-                     Source_Ptr (Int (Loc) + J));
+                     Loc + Source_Ptr (J));
                   return;
                end if;
             end loop;


diff --git a/gcc/ada/sinfo-utils.adb b/gcc/ada/sinfo-utils.adb
--- a/gcc/ada/sinfo-utils.adb
+++ b/gcc/ada/sinfo-utils.adb
@@ -191,7 +191,7 @@ package body Sinfo.Utils is
    function End_Location (N : Node_Id) return Source_Ptr is
       L : constant Valid_Uint := End_Span (N);
    begin
-      return Source_Ptr (Int (Sloc (N)) + UI_To_Int (L));
+      return Sloc (N) + Source_Ptr (UI_To_Int (L));
    end End_Location;
 
    --------------------
@@ -214,7 +214,7 @@ package body Sinfo.Utils is
    procedure Set_End_Location (N : Node_Id; S : Source_Ptr) is
    begin
       Set_End_Span (N,
-        UI_From_Int (Int (S) - Int (Sloc (N))));
+        UI_From_Int (Int (S - Sloc (N))));
    end Set_End_Location;
 
    --------------------------


diff --git a/gcc/ada/treepr.adb b/gcc/ada/treepr.adb
--- a/gcc/ada/treepr.adb
+++ b/gcc/ada/treepr.adb
@@ -1229,7 +1229,7 @@ package body Treepr is
 
          else
             Sfile := Get_Source_File_Index (Sloc (N));
-            Print_Int (Int (Sloc (N)) - Int (Source_Text (Sfile)'First));
+            Print_Int (Int (Sloc (N) - Source_Text (Sfile)'First));
             Write_Str ("  ");
             Write_Location (Sloc (N));
          end if;