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| author | Arnaud Charlet <charlet@gcc.gnu.org> | 2006-02-15 10:51:54 +0100 |
|---|---|---|
| committer | Arnaud Charlet <charlet@gcc.gnu.org> | 2006-02-15 10:51:54 +0100 |
| commit | 7a3f77d2a9a1ce40f15c192b60805947f4bcc58e (patch) | |
| tree | d9d222c4b53f8f572d22d3f3a5a9cac3a070c9c4 /gcc/ada | |
| parent | 51c40324f3965ff95b3b2696ac10142d765aad41 (diff) | |
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(Eval_Relational_Op): Use new Is_Known_Null flag to deal with case
of null = null, now known true.
From-SVN: r111106
Diffstat (limited to 'gcc/ada')
| -rw-r--r-- | gcc/ada/sem_eval.adb | 57 |
1 files changed, 29 insertions, 28 deletions
diff --git a/gcc/ada/sem_eval.adb b/gcc/ada/sem_eval.adb index 3e354ec..65005de 100644 --- a/gcc/ada/sem_eval.adb +++ b/gcc/ada/sem_eval.adb @@ -6,7 +6,7 @@ -- -- -- B o d y -- -- -- --- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2006, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- @@ -2202,25 +2202,29 @@ package body Sem_Eval is end if; end; - -- Another special case: comparisons against null for pointers that - -- are known to be non-null. This is useful when migrating from Ada95 - -- code when non-null restrictions are added to type declarations and - -- parameter specifications. + -- Another special case: comparisons of access types, where one or both + -- operands are known to be null, so the result can be determined. - elsif Is_Access_Type (Typ) - and then Comes_From_Source (N) - and then - ((Is_Entity_Name (Left) - and then Is_Known_Non_Null (Entity (Left)) - and then Nkind (Right) = N_Null) - or else - (Is_Entity_Name (Right) - and then Is_Known_Non_Null (Entity (Right)) - and then Nkind (Left) = N_Null)) - then - Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); - Warn_On_Known_Condition (N); - return; + elsif Is_Access_Type (Typ) then + if Known_Null (Left) then + if Known_Null (Right) then + Fold_Uint (N, Test (Nkind (N) = N_Op_Eq), False); + Warn_On_Known_Condition (N); + return; + + elsif Known_Non_Null (Right) then + Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); + Warn_On_Known_Condition (N); + return; + end if; + + elsif Known_Non_Null (Left) then + if Known_Null (Right) then + Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); + Warn_On_Known_Condition (N); + return; + end if; + end if; end if; -- Can only fold if type is scalar (don't fold string ops) @@ -4014,13 +4018,8 @@ package body Sem_Eval is elsif Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2) then - if Is_Generic_Actual_Type (T1) - and then Etype (T1) = T2 - then - return True; - else - return False; - end if; + return + Is_Generic_Actual_Type (T1) or else Is_Generic_Actual_Type (T2); -- Array type @@ -4060,11 +4059,13 @@ package body Sem_Eval is if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then return False; - elsif Ekind (T1) = E_Access_Subprogram_Type then + elsif Ekind (T1) = E_Access_Subprogram_Type + or else Ekind (T1) = E_Anonymous_Access_Subprogram_Type + then return Subtype_Conformant (Designated_Type (T1), - Designated_Type (T1)); + Designated_Type (T2)); else return Subtypes_Statically_Match |