[Ada] Add query for extended precision floating-point types

[Ada] Add query for extended precision floating-point types

[Pierre-Marie de Rodat]

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This query is used in GNATprove to identify extended precision (80-bits)
floating-point types.

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

gcc/ada/

	* sem_util.adb (Is_Extended_Precision_Floating_Point_Type): New
	function.
	* sem_util.ads (Is_Extended_Precision_Floating_Point_Type): New
	function.

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diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -17541,6 +17541,20 @@ package body Sem_Util is
       end if;
    end Is_Expression_Function_Or_Completion;
 
+   -----------------------------------------------
+   -- Is_Extended_Precision_Floating_Point_Type --
+   -----------------------------------------------
+
+   function Is_Extended_Precision_Floating_Point_Type
+     (E : Entity_Id) return Boolean is
+   begin
+      return Is_Floating_Point_Type (E)
+        and then Machine_Radix_Value (E) = Uint_2
+        and then Machine_Mantissa_Value (E) = Uint_64
+        and then Machine_Emax_Value (E) = Uint_2 ** Uint_14
+        and then Machine_Emin_Value (E) = Uint_3 - (Uint_2 ** Uint_14);
+   end Is_Extended_Precision_Floating_Point_Type;
+
    -----------------------
    -- Is_EVF_Expression --
    -----------------------


diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -2045,6 +2045,15 @@ package Sem_Util is
    --  Determine whether subprogram [body] Subp denotes an expression function
    --  or is completed by an expression function body.
 
+   function Is_Extended_Precision_Floating_Point_Type
+     (E : Entity_Id) return Boolean;
+   --  Return whether E is an extended precision floating point type,
+   --  characterized by:
+   --  . machine_radix = 2
+   --  . machine_mantissa = 64
+   --  . machine_emax = 2**14
+   --  . machine_emin = 3 - machine_emax
+
    function Is_EVF_Expression (N : Node_Id) return Boolean;
    --  Determine whether node N denotes a reference to a formal parameter of
    --  a specific tagged type whose related subprogram is subject to pragma