> On Fri, Jun 13, 2014 at 12:14 AM, Jan Hubicka <hubi...@ucw.cz> wrote:
> > Hi,
> > while updating vect_can_force_dr_alignment_p for section API I noticed the
> > predicate is bit confused about when it can update the alignment.
> >
> > We need to check that decl_binds_to_current_def_p and in case we compile
> > a partition also that the symbol is not homed in other partition.
> > Previous code was wrong i.e. for COMDATs, weaks or -fpic.
> >
> > Also when having an alias, only way to promote the alignment is to bump
> > up alignment of target.
> >
> > On the other hand comment about DECL_IN_CONSTANT_POOL seems confused - we
> > have
> > no sharing across partitions. I assume it was old hack and removed it.
>
> I don't think that code was confused. It's because of the way we emit
> the constant pool and use its hash (we duplicate the decl). Do a svn
> blame and see for the associated PR which you now broke again
> I guess. It wasn't about LTO I think.
It is middle-end/50494.
I have re-instantiated the check and also added back TREE_ASM_WRITTEN that is
needed
in the case of -fno-toplevel-reorder. I will try to look into the constant
pool output
machinery but indeed it is a nasty problem.
Thanks,
Honza
Index: ChangeLog
===================================================================
--- ChangeLog (revision 211689)
+++ ChangeLog (working copy)
@@ -1,5 +1,10 @@
2014-06-15 Jan Hubicka <hubi...@ucw.cz>
+ * tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Check again
+ DECL_IN_CONSTANT_POOL and TREE_ASM_WRITTEN.
+
+2014-06-15 Jan Hubicka <hubi...@ucw.cz>
+
* c-family/c-common.c (handle_tls_model_attribute): Use
set_decl_tls_model.
* cgraph.h (struct varpool_node): Add tls_model.
* tree.c (decl_tls_model, set_decl_tls_model): New functions.
Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c (revision 211688)
+++ tree-vect-data-refs.c (working copy)
@@ -5317,7 +5317,13 @@ vect_can_force_dr_alignment_p (const_tre
if (TREE_CODE (decl) != VAR_DECL)
return false;
- gcc_assert (!TREE_ASM_WRITTEN (decl));
+ /* With -fno-toplevel-reorder we may have already output the constant. */
+ if (TREE_ASM_WRITTEN (decl))
+ return false;
+
+ /* Constant pool entries may be shared and not properly merged by LTO. */
+ if (DECL_IN_CONSTANT_POOL (decl))
+ return false;
if (TREE_PUBLIC (decl) || DECL_EXTERNAL (decl))
{
