This is a regression present on all actives branches: the compiler doesn't
correctly align a field in a record type if there is a partial representation
clause on this record type that does not cover the field, but covers another
field which is aliased (or contains an aliased subcomponent) and whose nominal
alignment is smaller than that of the former field.
Tested on x86_64-suse-linux, applied on the mainline, 7 & 6 branches.
2017-12-14 Eric Botcazou <ebotca...@adacore.com>
* gcc-interface/decl.c (gnat_to_gnu_field): Do not set the alignment
of the enclosing record type if it is not already set.
2017-12-14 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/alignment13.adb: New test.
--
Eric Botcazou-- { dg-do run }
-- { dg-options "-gnatws" }
procedure Alignment13 is
type Rec is record
I1 : aliased Short_Integer;
I2 : Integer;
end record;
for Rec use record
I1 at 0 range 0 .. 15;
end record;
R : Rec;
begin
if R.I2'Bit_Position /= 32 then
raise Program_Error;
end if;
end;
Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c (revision 255631)
+++ gcc-interface/decl.c (working copy)
@@ -6890,7 +6890,8 @@ gnat_to_gnu_field (Entity_Id gnat_field,
{
const unsigned int type_align = TYPE_ALIGN (gnu_field_type);
- if (TYPE_ALIGN (gnu_record_type) < type_align)
+ if (TYPE_ALIGN (gnu_record_type)
+ && TYPE_ALIGN (gnu_record_type) < type_align)
SET_TYPE_ALIGN (gnu_record_type, type_align);
/* If the position is not a multiple of the alignment of the type,
