From 7d8ba0c67cfb68e3a7806b30c3075d06e8feeb7c Mon Sep 17 00:00:00 2001 From: Bob Duff Date: Tue, 27 Sep 2022 12:10:21 -0400 Subject: [PATCH] ada: Disable slice-of-component optimization in some cases This patch disables the Fast_Copy_Bitfield optimization in certain rare cases that currently do not work (crash in gigi). We could improve Expand_Assign_Array_Bitfield_Fast to handle these cases properly, but that change is delicate, so for now, we simply disable the optimization. gcc/ada/ * exp_ch5.adb (Expand_Assign_Array_Loop_Or_Bitfield): Disable the Fast_Copy_Bitfield optimization in certain cases. --- gcc/ada/exp_ch5.adb | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/gcc/ada/exp_ch5.adb b/gcc/ada/exp_ch5.adb index 209741c82cf8..9669737a79ba 100644 --- a/gcc/ada/exp_ch5.adb +++ b/gcc/ada/exp_ch5.adb @@ -1660,6 +1660,15 @@ package body Exp_Ch5 is return False; end Volatile_Or_Independent; + function Slice_Of_Packed_Component (L : Node_Id) return Boolean is + (Nkind (L) = N_Slice + and then Nkind (Prefix (L)) = N_Indexed_Component + and then Is_Bit_Packed_Array (Etype (Prefix (Prefix (L))))); + -- L is the left-hand side Name. Returns True if L is a slice of a + -- component of a bit-packed array. The optimization is disabled in + -- that case, because Expand_Assign_Array_Bitfield_Fast cannot + -- currently handle that case correctly. + L : constant Node_Id := Name (N); R : constant Node_Id := Expression (N); -- Left- and right-hand sides of the assignment statement @@ -1681,6 +1690,7 @@ package body Exp_Ch5 is and then not Reverse_Storage_Order (R_Type) and then Ndim = 1 and then Slices + and then not Slice_Of_Packed_Component (L) and then not Volatile_Or_Independent (L, L_Type) and then not Volatile_Or_Independent (R, R_Type) then -- 2.47.2