diff options
Diffstat (limited to 'gcc/ada/exp_util.adb')
| -rw-r--r-- | gcc/ada/exp_util.adb | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb index ba88516f485..d79ec31e527 100644 --- a/gcc/ada/exp_util.adb +++ b/gcc/ada/exp_util.adb @@ -1320,8 +1320,41 @@ package body Exp_Util is ---------------------- procedure Force_Evaluation (Exp : Node_Id; Name_Req : Boolean := False) is + Component_In_Lhs : Boolean := False; + Par : Node_Id; + begin - Remove_Side_Effects (Exp, Name_Req, Variable_Ref => True); + -- Loop to determine whether there is a component reference in + -- the left hand side if this appears on the left side of an + -- assignment statement. Needed to determine if form of result + -- must be a variable. + + Par := Exp; + while Present (Par) + and then Nkind (Par) = N_Selected_Component + loop + if Nkind (Parent (Par)) = N_Assignment_Statement + and then Par = Name (Parent (Par)) + then + Component_In_Lhs := True; + exit; + else + Par := Parent (Par); + end if; + end loop; + + -- If the expression is a selected component, it is being evaluated + -- as part of a discriminant check. If it is part of a left-hand + -- side, this is the last use of its value and it is safe to create + -- a renaming for it, rather than a temporary. In addition, if it + -- is not an addressable field, creating a temporary may be a problem + -- for gigi, or might drop the value of the assignment. Therefore, + -- if the expression is on the lhs of an assignment, remove side + -- effects without requiring a temporary, and create a renaming. + -- (See remove_side_effects for details). + + Remove_Side_Effects + (Exp, Name_Req, Variable_Ref => not Component_In_Lhs); end Force_Evaluation; ------------------------ |