ada: Preserve capability validity in address arithmetic

On CHERI targets where System.Address is a capability, arithmetic on
addresses should avoid converting to integers and instead use the
operations defined in System.Storage_Elements to perform the arithmetic
directly on the System.Address object. This preserves the capability's
validity throughout the calculation, ensuring that the resulting capability
can be dereferenced.

gcc/ada/

	* libgnat/s-carsi8.adb: Use operations from
	System.Storage_Elements for address arithmetic.
	* libgnat/s-carun8.adb: Likewise
	* libgnat/s-casi128.adb: Likewise
	* libgnat/s-casi16.adb: Likewise
	* libgnat/s-casi32.adb: Likewise
	* libgnat/s-casi64.adb: Likewise
	* libgnat/s-caun128.adb: Likewise
	* libgnat/s-caun16.adb: Likewise
	* libgnat/s-caun32.adb: Likewise
	* libgnat/s-caun64.adb: Likewise
	* libgnat/s-geveop.adb: Likewise

1 files changed, 5 insertions, 4 deletions

diff --git a/gcc/ada/libgnat/s-caun64.adb b/gcc/ada/libgnat/s-caun64.adb
index cca2069..e4246975 100644
--- a/gcc/ada/libgnat/s-caun64.adb
+++ b/gcc/ada/libgnat/s-caun64.adb
@@ -30,6 +30,7 @@
 ------------------------------------------------------------------------------
 
 with System.Address_Operations; use System.Address_Operations;
+with System.Storage_Elements;   use System.Storage_Elements;
 
 with Ada.Unchecked_Conversion;
 
@@ -82,8 +83,8 @@ package body System.Compare_Array_Unsigned_64 is
             end if;
 
             Clen := Clen - 1;
-            L := AddA (L, 8);
-            R := AddA (R, 8);
+            L := L + Storage_Offset (8);
+            R := R + Storage_Offset (8);
          end loop;
 
       --  Case of going by unaligned double words
@@ -99,8 +100,8 @@ package body System.Compare_Array_Unsigned_64 is
             end if;
 
             Clen := Clen - 1;
-            L := AddA (L, 8);
-            R := AddA (R, 8);
+            L := L + Storage_Offset (8);
+            R := R + Storage_Offset (8);
          end loop;
       end if;