[Ada] Optimize generation of checks for fixed-point types

gcc/ada/

	* checks.ads (Determine_Range_To_Discrete): New procedure.
	* checks.adb (Apply_Scalar_Range_Check): Call it to determine
	a range for the expression when the target type is discrete.
	And also apply the tests for discrete types to fixed-point
	types when they are treated as integers.
	(Apply_Type_Conversion_Checks): Apply checks to conversions
	involving fixed-point types when they are treated as integers.
	(Determine_Range) <N_Type_Conversion>: Factor out code into...
	(Determine_Range_To_Discrete): ...this new procedure and add
	support for fixed-point types when they are treated as integers.
	* einfo.ads (Type_High_Bound): Remove obsolete sentence.
	(Type_Low_Bound): Likewise.
	* exp_ch4.adb (Discrete_Range_Check): Remove obsolete code.
	(Real_Range_Check): Likewise.
	(Expand_N_Type_Conversion): In case of a no-op conversion, clear
	the Do_Range_Check flag on the operand before substituting it.
	Remove calls to Real_Range_Check and Discrete_Range_Check that
	are not guarded by the Do_Range_Check flag, and an assertion.
	* sem_res.adb (Resolve_Type_Conversion): Always apply range
	checks in GNATprove mode; in normal mode, use the updated type
	of the operand in the test against Universal_Fixed.  Remove
	obsolete code setting the Do_Range_Check flag at the end.

1 files changed, 15 insertions, 0 deletions

diff --git a/gcc/ada/checks.ads b/gcc/ada/checks.ads
index aca1b7e..d75c602 100644
--- a/gcc/ada/checks.ads
+++ b/gcc/ada/checks.ads
@@ -338,6 +338,21 @@ package Checks is
    --  For that to happen, the possibility of arguments of infinite or NaN
    --  value should be taken into account, which is not the case currently.
 
+   procedure Determine_Range_To_Discrete
+     (N            : Node_Id;
+      OK           : out Boolean;
+      Lo           : out Uint;
+      Hi           : out Uint;
+      Fixed_Int    : Boolean := False;
+      Assume_Valid : Boolean := False);
+   --  Similar to Determine_Range, but attempts to return a discrete range even
+   --  if N is not of a discrete type by doing a conversion. The Fixed_Int flag
+   --  if set causes any fixed-point values to be treated as though they were
+   --  discrete values (i.e. the underlying integer value is used), in which
+   --  case no conversion is needed. At the current time, this is used only for
+   --  discrete types, for fixed-point types if Fixed_Int is set, and also for
+   --  floating-point types in GNATprove, see Determine_Range_R above.
+
    procedure Install_Null_Excluding_Check (N : Node_Id);
    --  Determines whether an access node requires a run-time access check and
    --  if so inserts the appropriate run-time check.