diff options
| -rw-r--r-- | gcc/ada/sem_ch5.adb | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/gcc/ada/sem_ch5.adb b/gcc/ada/sem_ch5.adb index e5954a9..a26d4b7 100644 --- a/gcc/ada/sem_ch5.adb +++ b/gcc/ada/sem_ch5.adb @@ -1465,10 +1465,7 @@ package body Sem_Ch5 is function One_Bound (Original_Bound : Node_Id; Analyzed_Bound : Node_Id) return Node_Id; - -- Create one declaration followed by one assignment statement - -- to capture the value of bound. We create a separate assignment - -- in order to force the creation of a block in case the bound - -- contains a call that uses the secondary stack. + -- Capture value of bound and return captured value --------------- -- One_Bound -- @@ -1499,15 +1496,53 @@ package body Sem_Ch5 is then Analyze_And_Resolve (Original_Bound, Typ); return Original_Bound; - - else - Analyze_And_Resolve (Original_Bound, Typ); end if; + -- Here we need to capture the value + + Analyze_And_Resolve (Original_Bound, Typ); + Id := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('S')); + -- Normally, the best approach is simply to generate a constant + -- declaration that captures the bound. However, there is a nasty + -- case where this is wrong. If the bound is complex, and has a + -- possible use of the secondary stack, we need to generate a + -- separate assignment statement to ensure the creation of a block + -- which will release the secondary stack. + + -- We prefer the constant declaration, since it leaves us with a + -- proper trace of the value, useful in optimizations that get rid + -- of junk range checks. + + -- Probably we want something like the Side_Effect_Free routine + -- in Exp_Util, but for now, we just optimize the cases of 'Last + -- and 'First applied to an entity, since these are the important + -- cases for range check optimizations. + + if Nkind (Original_Bound) = N_Attribute_Reference + and then (Attribute_Name (Original_Bound) = Name_First + or else + Attribute_Name (Original_Bound) = Name_Last) + and then Is_Entity_Name (Prefix (Original_Bound)) + then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Id, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Typ, Loc), + Expression => Relocate_Node (Original_Bound)); + + Insert_Before (Parent (N), Decl); + Analyze (Decl); + Rewrite (Original_Bound, New_Occurrence_Of (Id, Loc)); + return Expression (Decl); + end if; + + -- Here we make a declaration with a separate assignment statement + Decl := Make_Object_Declaration (Loc, Defining_Identifier => Id, |