[dataflow]: PATCH COMMITTED to change the way register infomation is computed.
Kenneth Zadeck
zadeck@naturalbridge.com
Tue May 8 14:50:00 GMT 2007
This patch separates the operations that were done in the
DF_RI_PROBLEM into 3 categories:
1) The calculation of REG_DEAD and REG_UNUSED notes. This remains as
a dataflow problem, now called DF_NOTE.
2) The calculation of REG_N_SETS and REG_N_REFS. This was divided
into two cases:
a) For passes that do incremental dataflow rescanning AND do not
need to modify these, the calls were replace with calls to
DF_REG_DEF_COUNT and DF_REG_USE_COUNT. (Note that calls to
REG_N_REFS(i) were replaced with DF_REG_DEF_COUNT(i) +
DF_REG_USE_COUNT(i).
b) For passes that either needed to modify them or were not doing
incremental dataflow rescanning, a new datastructure was created.
This datastructure is initialized by calls to
regstat_init_n_sets_and_refs and must be freed by calls to
regstat_free_n_sets_and_refs. The used of REG_N_DEFS
(REG_N_REFS) that change the value have been changed to
SET_REG_N_DEFS (SET_REG_N_REFS) or INC_REG_N_DEFS
(INC_REG_N_REFS).
3) The calculation of REG_N_DEATHS, REG_LIVE_LENGTH, REG_N_CALLS_CROSSED,
REG_N_THROWING_CALLS_CROSSED and REG_BASIC_BLOCK is now done by
regstat_compute_ri and must be freed by regstat_free_ri. These
structures are currently only used by the register allocator and
regmove.
There were uses of (3) in the sh, however kaz has determined that
these were adding no value at all to the performance of the generated
code so they have been removed.
There still remains one call to REG_N_CALLS_CROSSED in sched-deps.
This should be removed at the earliest time since it is absolutely
bogus. There are better ways to compute when an insn cannot cross a
call and virtually every one of them would produce fewer dependencies.
I added regstat_bb_compute_calls_crossed and
regstat_bb_free_calls_crossed to support this use in the meantime.
This avoids the expensive calculation of REG_LIVE_LENGTH in the
regstat_compute_ri and must be freed by regstat_free_ri calls.
This breakup has allowed us to only compute these structures exactly
where they are needed which saves both time and space. Note the
removal of the calculation of REG_N_DEATHS from combine which
otherwise does not use any of (3).
This cleanup has allowed the removal of allocate_reg_life_data,
allocate_reg_info, and clear_reg_info_regno. It is now possible, but
not done in this patch to get rid of the no_new_pseudos bogusity.
All of this has made it possible fix the dataflow calls in the
register allocators so that now mimic the information flow of the
mainline. Not getting this right has been the source of several
performance and correctness regressions. We now only differ in that
we add the DF_UREC problem at the beginning of local-alloc rather than
computing make_accurate_live_analysis (which does the same thing on
mainline) at the start of global. This allows the information in (3)
to be computed over a more precise model of the program.
This patch has been bootstrapped and regression tested on x86-64,
x86-32, ppc-32 and ia-64.
Kenny
2007-05-08 Kenneth Zadeck <zadeck@naturalbridge.com>
* regrename.c (regrename_optimize): Renamed df_ri_add_problem to
df_note_add_problem.
* auto-inc-dec.c (rest_of_handle_auto_inc_dec): Ditto.
* sched_ebb.c (schedule_ebbs): Renamed df_ri_add_problem to
df_note_add_problem. Added call to regstat_compute_calls_crossed
and regstat_free_calls_crossed and deleted call to
allocate_reg_life_data.
* regstat.c (regstat_init_n_sets_and_refs,
regstat_free_n_sets_and_refs, regstat_bb_compute_ri,
regstat_compute_ri, regstat_free_ri,
regstat_bb_compute_calls_crossed, regstat_compute_calls_crossed,
regstat_free_calls_crossed): New functions.
* final.c (rest_of_handle_final): Removed call to free_reg_info.
* cfg.c (dump_reg_info): Many changes to accomodate new
implementation of REG_BASIC_BLOCK, REG_N_SETS, REG_N_DEATHS,
REG_N_CALLS_CROSSED.
* toplev.c (finalize): Removed call to free_reg_info.
* regs.h (REG_BASIC_BLOCK, REG_N_SETS, REG_N_REFS, REG_N_DEATHS,
REG_N_CALLS_CROSSED, REG_FREQ, REG_N_THROWING_CALLS_CROSSED,
REG_LIVE_LENGTH, REG_BASIC_BLOCK): Changed implementation.
(allocate_reg_life_data, allocate_reg_info, clear_reg_info_regno):
Removed.
* mode-switching.c (optimize_mode_switching): Removed call to
df_ri_add_problem.
* modulo-sched.c (sms_schedule): Renamed df_ri_add_problem to
df_note_add_problem. Added call to regstat_compute_calls_crossed
and regstat_free_calls_crossed
(rest_of_handle_sms): Deleted call to allocate_reg_info.
* global.c (compute_regsets): Moved all dataflow to local_alloc.
(rest_of_handle_global_alloc): Call regstat_free_n_sets_and_refs
and regstat_free_ri.
* ifcvt.c (dead_or_predicable, if_convert): Removed calls to
allocate_reg_info.
* timevar.def (TV_DF_NOTE): New timevar.
* regmove.c (copy_src_to_dest, regmove_optimize, fixup_match_1):
Changed calls to REG_N_SETS that changed the value to
INC_REG_N_SETS.
(regmove_optimize): Moved calls that compute df and register info
to after early out for flag_non_call_exceptions. Added calls to
regstat_init_n_sets_and_refs, regstat_compute_ri,
regstat_free_n_sets_and_refs and regstat_free_ri.
* local_alloc (local_alloc, equiv_init_movable_p): Added
NUM_FIXED_BLOCKS to tests for REG_BASIC_BLOCK.
(update_equiv_regs): Added code to update bitvectors when certain
local allocations are done. Changed REG_N_SETS to
DF_REG_DEF_COUNT. Added NUM_FIXED_BLOCKS to tests for
REG_BASIC_BLOCK.
(rest_of_handle_local_alloc): Moved computation of UREC from
global to here.
* function.c (regno_clobbered_at_setjmp): Added to test to see if
regno was valid. Moved function size test higher in call
heirarchy.
(setjmp_args_warning): Added tests to early out of check if
function is small or there are no setjmps.
* df.h (DF_RI, df_ri, DF_RI_LIFE, DF_RI_SETJMP, df_ri_add_problem,
df_ri_get_setjmp_crosses): Deleted.
(DF_NOTE, df_note, df_note_add_problem): Added.
* gcse (gcse_main): Removed computation of RI information and
removed calls to allocate_reg_info.
* init-regs.c (initialize_uninitialized_regs): Removed call to
allocate_reg_life_data.
* regclass.c (reg_info_data, reg_info_head, reg_pref_buffer,
allocate_reg_life_data, allocate_reg_info, clear_reg_info_regno):
Deleted.
(scan_one_insn): Changed some calls to REG_N_SETS and REG_N_REFS
to INC_REG_N_SETS and INC_REG_N_REFS.
(regclass): Allocate register information locally.
(free_reg_info): Changed the structures freed.
(reg_scan): Removed call to allocate_reg_info and changed call to
REG_N_SETS to DF_REG_DEF_COUNT.
* combine (try_combine, remove_death, distribute_notes): Removed
computation of REG_N_DEATHS. Changed some references to
REG_N_SETS to INC_REG_N_SETS.
(rest_of_handle_combine): Replaced call to df_ri_add_problem with
call to df_note_add_problem, and added call to
regstat_init_n_sets_and_refs and regstat_free_n_sets_and_refs.
* bb-reorder (rest_of_handle_partition_blocks): Removed call to
allocate_reg_life_data.
* df-problems.c (reg_n_info, df_ri_problem_p, df_ri_problem_data,
df_ri_alloc, df_ri_start_dump, df_ri_get_setjmp_crosses): Removed.
(print_note): Renamed df_print_note.
(df_kill_notes): Added parameters to save notes rather than just
let them die and remake them.
(df_set_note): New function.
(df_set_unused_notes_for_mw, df_set_dead_notes_for_mw,
df_create_unused_note, df_ri_bb_compute, df_ri_compute,
df_ri_free): Removed ri information computations.
(df_ri_bb_compute): Renamed to df_note_bb_compute.
(df_ri_compute): Renamed to df_note_compute.
(df_ri_free): Renamed to df_note_free.
(problem_RI): Renamed to problem_NOTE
(df_ri_add_problem): Renamed to df_note_add_problem.
* (reg-stack.c): Changed call to df_ri_add_problem to
df_note_add_problem.
* combine-stack-adj.c (rest_of_handle_stack_adjustments): Ditto.
* (Makefile.in): Added regstat.o.
* sched-rgn.c (schedule_insns): Changed call to df_ri_add_problem to
df_note_add_problem. Added calls to regstat_compute_calls_crossed
and regstat_free_calls_crossed.
* basic_block.h (REG_BLOCK_UNKNOWN, REG_BLOCK_GLOBAL,
REG_BASIC_BLOCK): Moved to regs.h.
* config/sparc/sparc.c (sparc_check_64): Changed REG_N_SETS to
DF_REG_DEF_COUNT.
* config/sh/sh.c (flow_dependent_p_1): Ditto.
(sh_md_init): Removed useless attempt to measure pressure on R0.
* config/m68k/m68k.c (m68k_output_mi_thunk): Removed call to
allocate_reg_info.
* reload1.c (delete_output_reload): Added NUM_FIXED_BLOCKS to
tests for REG_BASIC_BLOCK.
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