Forgot the ChangeLog entry in this commit; here it is.
* rtl.h (INSN_P): New macro.
(successor_phi_fn): New typedef.
(for_each_successor_phi): New prototype.
(in_ssa_form): New variable.
(PHI_NODE_P): Likewise.
* flow.c (calculate_global_regs_live): Add to new_live_at_end from
phi nodes in successors.
(mark_used_regs): Add PHI case.
(set_phi_alternative_reg): New function.
(life_analysis): Assert that dead code elimination is not selected
when in SSA form.
* toplev.c (to_ssa_time): New variable.
(from_ssa_time): Likewise.
(compile_file): Zero to_ssa_time and from_ssa_time.
Print time to convert to and from SSA.
(rest_of_compilation): Time convert_to_ssa and convert_from_ssa.
(print_time): Compute percent fraction as integer.
* ssa.c (PHI_NODE_P): Moved to rtl.h.
(convert_to_ssa): Check if we're already in SSA.
Don't eliminate dead code in life_analysis.
Rerun flow and life analysis at bottom.
(eliminate_phi): Use canonical regnos when adding nodes.
(mark_reg_in_phi): New function.
(mark_phi_and_copy_regs): Likewise.
(convert_from_ssa): Rerun life analysis at top.
Use coalesced partition.
Check for removing a phi node at the end of the block.
(compute_coalesced_reg_partition): New function.
(coalesce_regs_in_copies): Likewise.
(coalesce_reg_in_phi): Likewise.
(coalesce_regs_in_sucessor_phi_nodes): Likewise.
(for_each_successor_phi): Likewise.
(rename_context): New struct.
(rename_block): Use a rename_context with rename_insn_1. When
renaming sets of a subreg, emit a copy of the entire reg first.
(rename_insn_1): Treat data as a rename_context *. Save current
insn in set_data.
(rename_set_data): Add field set_insn.
* Makefile.in (HASHTAB_H): Move up in file.
(OBSTACK_H): New macro.
(collect2.o): Use OBSTACK_H in dependencies.
(sdbout.o): Likewise.
(emit-rtl.o): Likewise.
(simplify-rtx.o): Likewise.
(fix-header.o): Likewise.
(OBJS): Add conflict.o.
(conflict.o): New rule.
* basic-block.h: Include partition.h.
(conflict_graph): New typedef.
(conflict_graph_enum_fn): Likewise.
(conflict_graph_new): New prototype.
(conflict_graph_delete): Likewise.
(conflict_graph_add): Likewise.
(conflict_graph_conflict_p): Likewise.
(conflict_graph_enum): Likewise.
(conflict_graph_merge_regs): Likewise.
(conflict_graph_print): Likewise.
(conflict_graph_compute): Likewise.
* conflict.c: New file.