Do not use pragma Provide_Shift_Operators in Atree package

This pragma is relatively recent and may be problematic for the bootstrap.

gcc/ada/
	* atree.ads (Slot): Remove pragma Provide_Shift_Operators.
	(Shift_Left): New intrinsic function.
	(Shift_Right): Likewise.
	* atree.adb (Get_1_Bit_Val): Use Natural instead of Integer.
	(Get_2_Bit_Val): Likewise.
	(Get_4_Bit_Val): Likewise.
	(Get_8_Bit_Val): Likewise.
	(Set_1_Bit_Val): Likewise.
	(Set_2_Bit_Val): Likewise.
	(Set_4_Bit_Val): Likewise.
	(Set_8_Bit_Val): Likewise.

2 files changed, 14 insertions, 9 deletions

diff --git a/gcc/ada/atree.adb b/gcc/ada/atree.adb
index f1969d2..4d4dc43 100644
--- a/gcc/ada/atree.adb
+++ b/gcc/ada/atree.adb
@@ -564,7 +564,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          return Field_1_Bit (Shift_Right (S, V) and 1);
       end Get_1_Bit_Val;
@@ -577,7 +577,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          return Field_2_Bit (Shift_Right (S, V) and 3);
       end Get_2_Bit_Val;
@@ -590,7 +590,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          return Field_4_Bit (Shift_Right (S, V) and 15);
       end Get_4_Bit_Val;
@@ -603,7 +603,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          return Field_8_Bit (Shift_Right (S, V) and 255);
       end Get_8_Bit_Val;
@@ -626,7 +626,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset_Write (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          S := (S and not Shift_Left (1, V)) or Shift_Left (Slot (Val), V);
       end Set_1_Bit_Val;
@@ -639,7 +639,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset_Write (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          S := (S and not Shift_Left (3, V)) or Shift_Left (Slot (Val), V);
       end Set_2_Bit_Val;
@@ -652,7 +652,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset_Write (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          S := (S and not Shift_Left (15, V)) or Shift_Left (Slot (Val), V);
       end Set_4_Bit_Val;
@@ -665,7 +665,7 @@ package body Atree is
          pragma Debug (Validate_Node_And_Offset_Write (N, Offset / L));
 
          S : Slot renames Slots.Table (Node_Offsets.Table (N) + Offset / L);
-         V : constant Integer := Integer ((Offset mod L) * (Slot_Size / L));
+         V : constant Natural := Natural ((Offset mod L) * (Slot_Size / L));
       begin
          S := (S and not Shift_Left (255, V)) or Shift_Left (Slot (Val), V);
       end Set_8_Bit_Val;
diff --git a/gcc/ada/atree.ads b/gcc/ada/atree.ads
index fa0c9c1..efb8ca2 100644
--- a/gcc/ada/atree.ads
+++ b/gcc/ada/atree.ads
@@ -653,7 +653,12 @@ package Atree is
       Slot_Size : constant := 32;
       type Slot is mod 2**Slot_Size;
       for Slot'Size use Slot_Size;
-      pragma Provide_Shift_Operators (Slot);
+
+      function Shift_Left (S : Slot; V : Natural) return Slot;
+      pragma Import (Intrinsic, Shift_Left);
+
+      function Shift_Right (S : Slot; V : Natural) return Slot;
+      pragma Import (Intrinsic, Shift_Right);
 
       type Field_1_Bit  is mod 2**1;
       type Field_2_Bit  is mod 2**2;