For operations on unconstrained floating-point values, we do not want
overflow checks (since we expect to generate and handle IEEE INF and
NaN values). This corrects a problem where such checks were being set
if integer overflow was enabled. The following test when executed:
1. with Ada.Float_Text_IO;
2. with Ada.Long_Long_Float_Text_IO;
3. with Ada.Text_IO;
4. procedure IEEE_Conversions is
5. package FIO renames Ada.Float_Text_IO;
6. package LIO renames Ada.Long_Long_Float_Text_IO;
7. use Ada.Text_IO;
8. One : Long_Float := 1.0;
9. Zero : Long_Float := 0.0;
10. Infinity : Long_Float := One / Zero;
11. NaN : Long_Float := Zero / Zero;
12. begin
13. Put ("Float infinity: ");
14. FIO.Put (Float (Infinity));
15. New_Line;
16. Put ("Long_Long_Float infinity: ");
17. LIO.Put (Long_Long_Float (Infinity));
18. New_Line;
19. Put ("Float NaN: ");
20. FIO.Put (Float (NaN));
21. New_Line;
22. Put ("Long_Long_Float NaN: ");
23. LIO.Put (Long_Long_Float (NaN));
24. New_Line;
25. end;
should generate the output:
Float infinity: +Inf********
Long_Long_Float infinity: +Inf********************
Float NaN: NaN*********
Long_Long_Float NaN: NaN*********************
Before this change, a constraint error was raised
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-07-31 Robert Dewar <de...@adacore.com>
* checks.ads, checks.adb (Activate_Overflow_Check): Do not set flag for
unconstrained fpt ops.
Index: checks.adb
===================================================================
--- checks.adb (revision 213335)
+++ checks.adb (working copy)
@@ -389,10 +389,31 @@
procedure Activate_Overflow_Check (N : Node_Id) is
begin
- if not Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then
- Set_Do_Overflow_Check (N, True);
- Possible_Local_Raise (N, Standard_Constraint_Error);
+ -- Nothing to do for unconstrained floating-point types (the test for
+ -- Etype (N) being present seems necessary in some cases, should be
+ -- tracked down, but for now just ignore the check in this case ???)
+
+ if Present (Etype (N))
+ and then Is_Floating_Point_Type (Etype (N))
+ and then not Is_Constrained (Etype (N))
+
+ -- But do the check after all if float overflow checking enforced
+
+ and then not Check_Float_Overflow
+ then
+ return;
end if;
+
+ -- Nothing to do for Rem/Mod/Plus (overflow not possible)
+
+ if Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then
+ return;
+ end if;
+
+ -- Otherwise set the flag
+
+ Set_Do_Overflow_Check (N, True);
+ Possible_Local_Raise (N, Standard_Constraint_Error);
end Activate_Overflow_Check;
--------------------------
Index: checks.ads
===================================================================
--- checks.ads (revision 213292)
+++ checks.ads (working copy)
@@ -146,7 +146,9 @@
-- Always call this routine rather than calling Set_Do_Overflow_Check to
-- set an explicit value of True, to ensure handling the local raise case.
-- Note that this call has no effect for MOD, REM, and unary "+" for which
- -- overflow is never possible in any case.
+ -- overflow is never possible in any case. In addition, we do not set the
+ -- flag for unconstrained floating-point type operations, since we want to
+ -- allow for the generation of IEEE infinities in such cases.
procedure Activate_Range_Check (N : Node_Id);
pragma Inline (Activate_Range_Check);
