ada: Remove use of overlays in implementation of System.Pack_N units

The implementation uses an overlay between an address and an access value,
which is convoluted. This changes it to use a direct conversion instead.

No functional changes (and no changes to generated code at -O2).

gcc/ada/ChangeLog:

	* s-pack.adb.tmpl: Add "with System.Address_To_Access_Conversions".
	(Cluster_Ref): Delete.
	(AAC): New instance of System.Address_To_Access_Conversions.
	(Rev_Cluster_Ref): Delete.
	(Rev_ACC): New instance of System.Address_To_Access_Conversions.
	(ClusterU_Ref): Delete.
	(AACU): New instance of System.Address_To_Access_Conversions.
	(Rev_ClusterU_Ref): Delete.
	(Rev_ACCU): New instance of System.Address_To_Access_Conversions.
	(Get_@@): Use a direct address-to-access conversion.
	(GetU_@@): Likewise.
	(Set_@@): Likewise.
	(SetU_@@): Likewise.
	* libgnat/s-pack03.adb: Regenerate.
	* libgnat/s-pack05.adb: Likewise.
	* libgnat/s-pack06.adb: Likewise.
	* libgnat/s-pack07.adb: Likewise.
	* libgnat/s-pack09.adb: Likewise.
	* libgnat/s-pack10.adb: Likewise.
	* libgnat/s-pack100.adb: Likewise.
	* libgnat/s-pack101.adb: Likewise.
	* libgnat/s-pack102.adb: Likewise.
	* libgnat/s-pack103.adb: Likewise.
	* libgnat/s-pack104.adb: Likewise.
	* libgnat/s-pack105.adb: Likewise.
	* libgnat/s-pack106.adb: Likewise.
	* libgnat/s-pack107.adb: Likewise.
	* libgnat/s-pack108.adb: Likewise.
	* libgnat/s-pack109.adb: Likewise.
	* libgnat/s-pack11.adb: Likewise.
	* libgnat/s-pack110.adb: Likewise.
	* libgnat/s-pack111.adb: Likewise.
	* libgnat/s-pack112.adb: Likewise.
	* libgnat/s-pack113.adb: Likewise.
	* libgnat/s-pack114.adb: Likewise.
	* libgnat/s-pack115.adb: Likewise.
	* libgnat/s-pack116.adb: Likewise.
	* libgnat/s-pack117.adb: Likewise.
	* libgnat/s-pack118.adb: Likewise.
	* libgnat/s-pack119.adb: Likewise.
	* libgnat/s-pack12.adb: Likewise.
	* libgnat/s-pack120.adb: Likewise.
	* libgnat/s-pack121.adb: Likewise.
	* libgnat/s-pack122.adb: Likewise.
	* libgnat/s-pack123.adb: Likewise.
	* libgnat/s-pack124.adb: Likewise.
	* libgnat/s-pack125.adb: Likewise.
	* libgnat/s-pack126.adb: Likewise.
	* libgnat/s-pack127.adb: Likewise.
	* libgnat/s-pack13.adb: Likewise.
	* libgnat/s-pack14.adb: Likewise.
	* libgnat/s-pack15.adb: Likewise.
	* libgnat/s-pack17.adb: Likewise.
	* libgnat/s-pack18.adb: Likewise.
	* libgnat/s-pack19.adb: Likewise.
	* libgnat/s-pack20.adb: Likewise.
	* libgnat/s-pack21.adb: Likewise.
	* libgnat/s-pack22.adb: Likewise.
	* libgnat/s-pack23.adb: Likewise.
	* libgnat/s-pack24.adb: Likewise.
	* libgnat/s-pack25.adb: Likewise.
	* libgnat/s-pack26.adb: Likewise.
	* libgnat/s-pack27.adb: Likewise.
	* libgnat/s-pack28.adb: Likewise.
	* libgnat/s-pack29.adb: Likewise.
	* libgnat/s-pack30.adb: Likewise.
	* libgnat/s-pack31.adb: Likewise.
	* libgnat/s-pack33.adb: Likewise.
	* libgnat/s-pack34.adb: Likewise.
	* libgnat/s-pack35.adb: Likewise.
	* libgnat/s-pack36.adb: Likewise.
	* libgnat/s-pack37.adb: Likewise.
	* libgnat/s-pack38.adb: Likewise.
	* libgnat/s-pack39.adb: Likewise.
	* libgnat/s-pack40.adb: Likewise.
	* libgnat/s-pack41.adb: Likewise.
	* libgnat/s-pack42.adb: Likewise.
	* libgnat/s-pack43.adb: Likewise.
	* libgnat/s-pack44.adb: Likewise.
	* libgnat/s-pack45.adb: Likewise.
	* libgnat/s-pack46.adb: Likewise.
	* libgnat/s-pack47.adb: Likewise.
	* libgnat/s-pack48.adb: Likewise.
	* libgnat/s-pack49.adb: Likewise.
	* libgnat/s-pack50.adb: Likewise.
	* libgnat/s-pack51.adb: Likewise.
	* libgnat/s-pack52.adb: Likewise.
	* libgnat/s-pack53.adb: Likewise.
	* libgnat/s-pack54.adb: Likewise.
	* libgnat/s-pack55.adb: Likewise.
	* libgnat/s-pack56.adb: Likewise.
	* libgnat/s-pack57.adb: Likewise.
	* libgnat/s-pack58.adb: Likewise.
	* libgnat/s-pack59.adb: Likewise.
	* libgnat/s-pack60.adb: Likewise.
	* libgnat/s-pack61.adb: Likewise.
	* libgnat/s-pack62.adb: Likewise.
	* libgnat/s-pack63.adb: Likewise.
	* libgnat/s-pack65.adb: Likewise.
	* libgnat/s-pack66.adb: Likewise.
	* libgnat/s-pack67.adb: Likewise.
	* libgnat/s-pack68.adb: Likewise.
	* libgnat/s-pack69.adb: Likewise.
	* libgnat/s-pack70.adb: Likewise.
	* libgnat/s-pack71.adb: Likewise.
	* libgnat/s-pack72.adb: Likewise.
	* libgnat/s-pack73.adb: Likewise.
	* libgnat/s-pack74.adb: Likewise.
	* libgnat/s-pack75.adb: Likewise.
	* libgnat/s-pack76.adb: Likewise.
	* libgnat/s-pack77.adb: Likewise.
	* libgnat/s-pack78.adb: Likewise.
	* libgnat/s-pack79.adb: Likewise.
	* libgnat/s-pack80.adb: Likewise.
	* libgnat/s-pack81.adb: Likewise.
	* libgnat/s-pack82.adb: Likewise.
	* libgnat/s-pack83.adb: Likewise.
	* libgnat/s-pack84.adb: Likewise.
	* libgnat/s-pack85.adb: Likewise.
	* libgnat/s-pack86.adb: Likewise.
	* libgnat/s-pack87.adb: Likewise.
	* libgnat/s-pack88.adb: Likewise.
	* libgnat/s-pack89.adb: Likewise.
	* libgnat/s-pack90.adb: Likewise.
	* libgnat/s-pack91.adb: Likewise.
	* libgnat/s-pack92.adb: Likewise.
	* libgnat/s-pack93.adb: Likewise.
	* libgnat/s-pack94.adb: Likewise.
	* libgnat/s-pack95.adb: Likewise.
	* libgnat/s-pack96.adb: Likewise.
	* libgnat/s-pack97.adb: Likewise.
	* libgnat/s-pack98.adb: Likewise.
	* libgnat/s-pack99.adb: Likewise.

1 files changed, 15 insertions, 8 deletions

diff --git a/gcc/ada/libgnat/s-pack119.adb b/gcc/ada/libgnat/s-pack119.adb
index dd27b4c..5351727 100644
--- a/gcc/ada/libgnat/s-pack119.adb
+++ b/gcc/ada/libgnat/s-pack119.adb
@@ -29,6 +29,7 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
+with System.Address_To_Access_Conversions;
 with System.Storage_Elements;
 with System.Unsigned_Types;
 
@@ -69,12 +70,16 @@ package body System.Pack_119 is
    --  Use maximum possible alignment, given the bit field size, since this
    --  will result in the most efficient code possible for the field.
 
-   type Cluster_Ref is access Cluster;
+   package AAC is new Address_To_Access_Conversions (Cluster);
+   --  We convert addresses to access values and dereference them instead of
+   --  directly using overlays in order to work around the implementation of
+   --  the RM 13.3(19) clause, which would pessimize the generated code.
 
    type Rev_Cluster is new Cluster
      with Bit_Order            => Reverse_Bit_Order,
           Scalar_Storage_Order => Reverse_Bit_Order;
-   type Rev_Cluster_Ref is access Rev_Cluster;
+
+   package Rev_AAC is new Address_To_Access_Conversions (Rev_Cluster);
 
    ------------
    -- Get_119 --
@@ -85,9 +90,10 @@ package body System.Pack_119 is
       N       : Natural;
       Rev_SSO : Boolean) return Bits_119
    is
-      A  : constant System.Address := Arr + Bits * Ofs (Uns (N) / 8);
-      C  : Cluster_Ref     with Address => A'Address, Import;
-      RC : Rev_Cluster_Ref with Address => A'Address, Import;
+      A  : constant System.Address         := Arr + Bits * Ofs (Uns (N) / 8);
+      C  : constant AAC.Object_Pointer     := AAC.To_Pointer (A);
+      RC : constant Rev_AAC.Object_Pointer := Rev_AAC.To_Pointer (A);
+
    begin
       return
          (if Rev_SSO then
@@ -124,9 +130,10 @@ package body System.Pack_119 is
       E       : Bits_119;
       Rev_SSO : Boolean)
    is
-      A  : constant System.Address := Arr + Bits * Ofs (Uns (N) / 8);
-      C  : Cluster_Ref     with Address => A'Address, Import;
-      RC : Rev_Cluster_Ref with Address => A'Address, Import;
+      A  : constant System.Address         := Arr + Bits * Ofs (Uns (N) / 8);
+      C  : constant AAC.Object_Pointer     := AAC.To_Pointer (A);
+      RC : constant Rev_AAC.Object_Pointer := Rev_AAC.To_Pointer (A);
+
    begin
       if Rev_SSO then
          case N07 (Uns (N) mod 8) is