checks.adb (Generate_Range_Check): Replace type conversions with unchecked conversions to support the case of...

2009-07-07  Gary Dismukes  <dismukes@adacore.com>

	* checks.adb (Generate_Range_Check): Replace type conversions with
	unchecked conversions to support the case of performing range checks
	on Enum'Val (permits integer values to be converted to enumeration).

	* exp_attr.adb (Expand_N_Attribute_Reference, cases Attribute_Pred,
	Attribute_Succ): Set Do_Range_Check to False before calling
	Expand_Pred_Succ, to prevent gigi from generating any range checks.
	(Expand_N_Attribute_Reference, case Attribute_Val):
	Generate a range check when needed (and set Do_Range_Check to False).

	* exp_ch3.adb (Expand_N_Object_Declaration): Generate a range check on
	scalar object initialization if needed.

	* exp_ch4.adb (Expand_Allocator_Expression): Generate range checks
	when needed on scalar allocators.
	(Expand_N_Qualified_Expression): Generate range check when needed.
	(Expand_N_Slice): Remove call to Enable_Range_Check on slice ranges.
	Checks on slice ranges handled in Resolve_Slice.

	* exp_ch5.adb (Expand_N_Assignment_Statement): Generate a range check,
	when needed, for all scalar assignments, not just discrete.
	(Expand_Simple_Function_Return): Resolve the conversion created for a
	scalar function return so that the conversion will get expanded to
	generate a possible constraint check.

	* exp_ch6.adb (Expand_Actuals): Call Add_Call_By_Copy_Code for out and
	in out scalar actuals when subtypes don't match, to ensure generation
	of return checks (and set Do_Range_Check to False).
	(Expand_Call): Uncomment code to perform range checks, but make it apply
	only to in and in out parameters (checks on parameter returns are
	handled in Expand_Actuals). If a scalar actual for a call to a derived
	subprogram is marked as needing a range check, peform it here (and set
	Do_Range_Check to False).

	* sem_aggr.adb (Resolve_*_Aggregate.Resolve_Aggr_Expr): Generate a
	range check on scalar component associations when needed.

	* sem_eval.adb (In_Subrange_Of): Return False when the first type has
	infinities but the second type does not, as these aren't compatible
	floating-point types.

	* sem_res.adb (Resolve_Slice): In the case where the prefix of the
	slice is itself a slice, pick up the Etype of the prefix. This handles
	the case where the prefix was an Image attribute expanded to a slice,
	and ensures that we get the subtype with the slice constraint rather
	than the unconstrained subbtype of the 'Image.

From-SVN: r149318