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sem_ch4.adb (Is_Empty_Range): Use bounds of index type to determine whether an array is empty when...

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2012-10-02  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch4.adb (Is_Empty_Range): Use bounds of index type
	to determine whether an array is empty when optimizing
	a quantified expression over a null range. Use of RM_Size
	was incorrect. Analyze condition before constant-folding the
	expression to catch potential errors. Modify the error message
	to avoid mathematical terminology.

From-SVN: r191958
This commit is contained in:
Ed Schonberg 2012-10-02 08:10:54 +00:00 • committed by Arnaud Charlet
parent 538dbb562f
commit 4856cc2a7d
2 changed files with 31 additions and 10 deletions
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9
gcc/ada/ChangeLog
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@ -1,3 +1,12 @@
2012-10-02 Ed Schonberg <schonberg@adacore.com>
* sem_ch4.adb (Is_Empty_Range): Use bounds of index type
to determine whether an array is empty when optimizing
a quantified expression over a null range. Use of RM_Size
was incorrect. Analyze condition before constant-folding the
expression to catch potential errors. Modify the error message
to avoid mathematical terminology.
2012-10-02 Robert Dewar <dewar@adacore.com>
* usage.adb, gnat_rm.texi, vms_data.ads: Add entry for

32
gcc/ada/sem_ch4.adb
View file

@ -3404,27 +3404,37 @@ package body Sem_Ch4 is
procedure Analyze_Quantified_Expression (N : Node_Id) is
QE_Scop : Entity_Id;
function Is_Empty_Range (Typ : Entity_Id) return Boolean;
function Is_Empty_Range (Typ : Entity_Id) return Boolean;
-- If the iterator is part of a quantified expression, and the range is
-- known to be statically empty, emit a warning and replace expression
-- with its static value.
-- with its static value. Returns True if the replacement occurs.
function Is_Empty_Range (Typ : Entity_Id) return Boolean is
Loc : constant Source_Ptr := Sloc (N);
--------------------
-- Is_Empty_Range --
--------------------
function Is_Empty_Range (Typ : Entity_Id) return Boolean is
Loc : constant Source_Ptr := Sloc (N);
begin
if Is_Array_Type (Typ)
and then Size_Known_At_Compile_Time (Typ)
and then RM_Size (Typ) = 0
and then Compile_Time_Known_Bounds (Typ)
and then
(Expr_Value (Type_Low_Bound (Etype (First_Index (Typ))))
> Expr_Value (Type_High_Bound (Etype (First_Index (Typ)))))
then
Preanalyze_And_Resolve (Condition (N), Standard_Boolean);
if All_Present (N) then
Error_Msg_N ("?universal quantified expression "
& "over a null range has value True", N);
Error_Msg_N
("?quantified expression with ALL "
& "over a null range has value True", N);
Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
else
Error_Msg_N ("?existential quantified expression "
& "over a null range has value False", N);
Error_Msg_N
("?quantified expression with SOME "
& "over a null range has value False", N);
Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
end if;
@ -3436,6 +3446,8 @@ package body Sem_Ch4 is
end if;
end Is_Empty_Range;
-- Start of processing for Analyze_Quantified_Expression
begin
Check_SPARK_Restriction ("quantified expression is not allowed", N);