Re: Merging stmt_ann_d into tree_statement_list_node

[Kazu Hirata <kazu at cs dot umass dot edu>]

Hi Zdenek,

> guessing from (*) below, you probably just forgot to mention that it also
> involves changing SSA_NAME_DEF_STMT to point to the
> tree_statement_list_node rather than the statement itself,
> otherwise there is no way how to get the
> annotation for SSA_NAME_DEF_STMT (name)?

I am not planning to change SSA_NAME_DEF_STMT yet.  If stmt_ann is
embedded into tree_statement_list_node, we can compute the address of
tree_statement_list_node from that of stmt_ann.  I am planning to keep
a pointer from a statement proper to a stmt_ann for now.

> It is definitely a good idea, IMHO.

Thanks!

I might need your help later as a loop optimizer expert.  I just found
yesterday that tree-ssa-loop-im.c:schedule_sm is using stmt_ann before
a statement proper is linked to a basic block.  Specifically, it
creates a statement, attaches a stmt_ann, and puts it on edge.  We
probably have to one of the following.

1) delay the creation of stmt_ann until after a statement is linked,

2) create a stmt_ann just like we do now, and then copy its contents
   to stmt_ann embedded in tree_statement_list_node, or

3) create a tree_statement_list_node in schedule_sm, which contains
   stmt_ann, and link it to a basic block.  (This option would require
   bigger changes as we are currently supposed to put a statement in
   PENDING_STMT, not a tree_statement_list_node.  Plus, bsi_insert_*
   and tsi_link_* stuff all expect a statement.)

Right now I am just instrumenting stmt_ann to see where people are
using stmt_ann while a statement is not linked to a basic block.

Kazu Hirata