dce.c (init_dce): Only initialize the obstacks for the fast pass.
* dce.c (init_dce): Only initialize the obstacks for the fast pass.
(fini_dce): Only release them for the fast pass.
(end_ud_dce): Delete.
(rest_of_handle_ud_dce): Do not modify df_in_progress.
Call fini_dce instead of end_ud_dce.
(rest_of_handle_fast_dce): Do not modify df_in_progress.
(run_fast_df_dce): Reset df_in_progress to false on exit.