[RFC] removing statement walking from domwalk.c?

[Paolo Bonzini]

Hi all,

for my next patch to fwprop for PR33928, I need a dominator walk and I
would have liked to use domwalk.c; however it is only for trees at the
moment, while I need it on RTL.

I was thinking therefore of removing the following fields from the
dominator walk callbacks:

  BOOL_BITFIELD walk_stmts_backward : 1;

  void (*before_dom_children_walk_stmts) (struct dom_walk_data *,
                                          basic_block,
                                          gimple_stmt_iterator);

  void (*after_dom_children_walk_stmts) (struct dom_walk_data *,
                                         basic_block,
                                         gimple_stmt_iterator);

(the last is unused anyway).  After merging the before_stmts/after_stmts
callbacks into one, the callbacks would be initialize_block_local_data,
before_dom_children and after_dom_children.  I would of course take care
of adapting the current uses, which would be quite mechanical (and
anyway there are just half a dozen).

Any objections?  I don't know exactly when I'll get to it, but I hope by
the end of June.

Paolo