re PR debug/41616 (Variables promoted to Gimple registers by aliasing are not getting debug statements.)

gcc/ChangeLog:
PR debug/41616
* tree-into-ssa.c (insert_phi_nodes_for): Build debug bind stmts
on updates too.
(maybe_register_def): Likewise.  Take stmt iterator.
(rewrite_update_stmt): Take stmt iterator and pass it on.
(rewrite_update_enter_block): Pass stmt iterator.
gcc/testsuite/ChangeLog:
PR debug/41616
* gcc.dg/guality/pr41616-1.c: New.

From-SVN: r152662