* dominance.c: New file.
        * Makefile.in (OBJS): Add dominance.o.

        * flow.c (compute_flow_dominators): Remove.
        (compute_immediate_dominators): Remove.
        (compute_immediate_postdominators): Remove.
        * basic-block.h: Remove their prototypes.
        (calculate_dominance_info): Add prototype.

        * dce.c (eliminate_dead_code): Change calls to above functions.
        Don't compute dominators but only immediate dominators.
        * flow.c (flow_loops_find): Change callers.
        * gcse.c (compute_code_hoist_data): Likewise.
        * haifa-sched.c (schedule_insns): Likewise.
        * ifcvt.c (if_convert): Likewise.
        * ssa.c (convert_to_ssa): Likewise, and only compute immediate
        dominators.

From-SVN: r37449

	* dce.c: Remove all uses of assert.
	* dwarf2out.c: Likewise.
	* dwarfout.c: Likewise.
	* ssa.c: Likewise.

From-SVN: r35438

	* Makefile.in (OBJS): Added dce.o.
	(ssa.o): Updated target to include ssa.h.
	(flow.o): Likewise.
	(toplev.o): Likewise.
	(dce.o): Created target.
	* basic-block.h: Added comments.
	(INVALID_BLOCK): Added definition.
	(connect_infinite_loops_to_exit): Added declaration.
	Moved SSA declarations to ssa.h.
	* flow.c: Added inclusion of ssa.h.
	(struct depth_first_search_dsS, depth_first_search_ds):
	Added definitions.
	(compute_immediate_postdominators): Added definition.
	(connect_infinite_loops_to_exit): Likewise.
	(flow_dfs_compute_reverse_init): Likewise.
	(flow_dfs_compute_reverse_add_bb): Likewise.
	(flow_dfs_compute_reverse_execute): Likewise.
	(flow_dfs_compute_reverse_finish): Likewise.
	* rtl.h (rtx/in_struct): Added use to determine insn necessity.
	(LABEL_P): Added definition.
	(JUMP_P): Likewise.
	(NOTE_P): Likewise.
	(BARRIER_P): Likewise.
	(JUMP_TABLE_DATA_P): Likewise.
	(INSN_DEAD_CODE_P): Likewise.
	* ssa.c: Replaced inclusions with ssa.h inclusion.
	(CONVERT_HARD_REGISTER_TO_SSA_P): Moved to ssa.h.
	(rename_registers): Removed unnecessary variables.
	* ssa.h: Created by moving declarations from ssa.c and
	basic-block.h.
	* timevar.def: Defined TV_DEAD_CODE_ELIM.
	* toplev.c: Added ssa.h inclusion.
	(dump_file_index): Added DFI_dce.
	(dump_file): Added "dce" entry.
	Defined flag_ssa.
	(f_options): Added dce entry.
	* invoke.texi: Document -fdce.  Emphasize experimental status of
	-fssa.

Co-Authored-By: Mark Mitchell <mark@codesourcery.com>

From-SVN: r35419