https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79256
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
So there's ADJUST_FIELD_ALIGN (x86_field_alignment) but the interface is not
usable from within get_object_alignment_2 at
/* When EXP is an actual memory reference then we can use
TYPE_ALIGN of a pointer indirection to derive alignment.
Do so only if get_pointer_alignment_1 did not reveal absolute
alignment knowledge and if using that alignment would
improve the situation. */
if (!addr_p
&& TYPE_ALIGN (TREE_TYPE (exp)) > align)
align = TYPE_ALIGN (TREE_TYPE (exp));
of course there's min_align_of_type () that just builds a FIELD_DECL for
this purpose (ugh). But it would mean that the above needs to use
min_align_of_type (). Ugh.
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c (revision 244974)
+++ gcc/builtins.c (working copy)
@@ -334,9 +334,11 @@ get_object_alignment_2 (tree exp, unsign
Do so only if get_pointer_alignment_1 did not reveal absolute
alignment knowledge and if using that alignment would
improve the situation. */
+ unsigned int talign;
if (!addr_p && !known_alignment
- && TYPE_ALIGN (TREE_TYPE (exp)) > align)
- align = TYPE_ALIGN (TREE_TYPE (exp));
+ && (talign = min_align_of_type (TREE_TYPE (exp)) * BITS_PER_UNIT)
+ && talign > align)
+ align = talign;
else
{
/* Else adjust bitpos accordingly. */
