On Wed, Mar 16, 2011 at 09:46:20AM +0100, Paolo Bonzini wrote:
On 03/16/2011 12:12 AM, Kenneth Zadeck wrote:
so how much time does this save?
I agree that this is a useful simplification, but it seems unlikely to
be that important in real code.
it seems like the 5000 store test would in general provide a better
safety valve.
I think having both is a good idea.
Here is the second patch, ok for both to trunk if this one passes
bootstrap/regtest?
With just this patch alone on the testcase with the default
--param=max-dse-active-local-stores=5000 cc1 spends 18.9 seconds
in DSE1+DSE2, with =1000 just 4 seconds and with =10 0.4 seconds.
With the earlier patch in addition to this one the time in DSE1+DSE2
is 0.3 seconds no matter what the parameter is.
2011-03-16 Jakub Jelinek<ja...@redhat.com>
PR rtl-optimization/48141
* params.def (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES): New.
* dse.c: Include params.h.
(active_local_stores_len): New variable.
(add_wild_read, dse_step1): Clear it when setting active_local_stores
to NULL.
(record_store, check_mem_read_rtx): Decrease it when removing
from the chain.
(scan_insn): Likewise. Increase it when adding to chain, if it
reaches PARAM_MAX_DSE_ACTIVE_LOCAL_STORES limit, set to 1 and
set active_local_stores to NULL before the addition.
* Makefile.in (dse.o): Depend on $(PARAMS_H).
--- gcc/params.def.jj 2011-02-15 15:42:27.000000000 +0100
+++ gcc/params.def 2011-03-16 12:20:16.000000000 +0100
@@ -698,6 +698,12 @@ DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
"The maximum number of instructions ready to be issued to be considered by
the scheduler during the first scheduling pass",
100, 0, 0)
+/* This is the maximum number of active local stores RTL DSE will consider. */
+DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
+ "max-dse-active-local-stores",
+ "Maximum number of active local stores in RTL dead store elimination",
+ 5000, 0, 0)
+
/* Prefetching and cache-optimizations related parameters. Default values are
usually set by machine description. */
--- gcc/dse.c.jj 2011-02-15 15:42:26.000000000 +0100
+++ gcc/dse.c 2011-03-16 12:34:18.000000000 +0100
@@ -47,6 +47,7 @@ along with GCC; see the file COPYING3.
#include "optabs.h"
#include "dbgcnt.h"
#include "target.h"
+#include "params.h"
/* This file contains three techniques for performing Dead Store
Elimination (dse).
@@ -387,6 +388,7 @@ static alloc_pool insn_info_pool;
/* The linked list of stores that are under consideration in this
basic block. */
static insn_info_t active_local_stores;
+static int active_local_stores_len;
struct bb_info
{
@@ -947,6 +949,7 @@ add_wild_read (bb_info_t bb_info)
}
insn_info->wild_read = true;
active_local_stores = NULL;
+ active_local_stores_len = 0;
}
@@ -1538,6 +1541,7 @@ record_store (rtx body, bb_info_t bb_inf
{
insn_info_t insn_to_delete = ptr;
+ active_local_stores_len--;
if (last)
last->next_local_store = ptr->next_local_store;
else
@@ -2074,6 +2078,7 @@ check_mem_read_rtx (rtx *loc, void *data
if (dump_file)
dump_insn_info ("removing from active", i_ptr);
+ active_local_stores_len--;
if (last)
last->next_local_store = i_ptr->next_local_store;
else
@@ -2163,6 +2168,7 @@ check_mem_read_rtx (rtx *loc, void *data
if (dump_file)
dump_insn_info ("removing from active", i_ptr);
+ active_local_stores_len--;
if (last)
last->next_local_store = i_ptr->next_local_store;
else
@@ -2222,6 +2228,7 @@ check_mem_read_rtx (rtx *loc, void *data
if (dump_file)
dump_insn_info ("removing from active", i_ptr);
+ active_local_stores_len--;
if (last)
last->next_local_store = i_ptr->next_local_store;
else
@@ -2426,6 +2433,7 @@ scan_insn (bb_info_t bb_info, rtx insn)
if (dump_file)
dump_insn_info ("removing from active", i_ptr);
+ active_local_stores_len--;
if (last)
last->next_local_store = i_ptr->next_local_store;
else
@@ -2453,6 +2461,12 @@ scan_insn (bb_info_t bb_info, rtx insn)
fprintf (dump_file, "handling memset as BLKmode store\n");
if (mems_found == 1)
{
+ if (active_local_stores_len++
+>= PARAM_VALUE (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES))
+ {
+ active_local_stores_len = 1;
+ active_local_stores = NULL;
+ }
insn_info->next_local_store = active_local_stores;
active_local_stores = insn_info;
}
@@ -2496,6 +2510,12 @@ scan_insn (bb_info_t bb_info, rtx insn)
it as cannot delete. This simplifies the processing later. */
if (mems_found == 1)
{
+ if (active_local_stores_len++
+>= PARAM_VALUE (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES))
+ {
+ active_local_stores_len = 1;
+ active_local_stores = NULL;
+ }
insn_info->next_local_store = active_local_stores;
active_local_stores = insn_info;
}
@@ -2534,6 +2554,7 @@ remove_useless_values (cselib_val *base)
if (del)
{
+ active_local_stores_len--;
if (last)
last->next_local_store = insn_info->next_local_store;
else
@@ -2584,6 +2605,7 @@ dse_step1 (void)
= create_alloc_pool ("cse_store_info_pool",
sizeof (struct store_info), 100);
active_local_stores = NULL;
+ active_local_stores_len = 0;
cselib_clear_table ();
/* Scan the insns. */
--- gcc/Makefile.in.jj 2011-02-02 16:30:50.000000000 +0100
+++ gcc/Makefile.in 2011-03-16 12:26:12.000000000 +0100
@@ -3070,7 +3070,7 @@ dse.o : dse.c $(CONFIG_H) $(SYSTEM_H) co
$(TREE_H) $(TM_P_H) $(REGS_H) hard-reg-set.h $(FLAGS_H) insn-config.h \
$(RECOG_H) $(EXPR_H) $(DF_H) cselib.h $(DBGCNT_H) $(TIMEVAR_H) \
$(TREE_PASS_H) alloc-pool.h $(ALIAS_H) dse.h $(OPTABS_H) $(TARGET_H) \
- $(BITMAP_H)
+ $(BITMAP_H) $(PARAMS_H)
fwprop.o : fwprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(DIAGNOSTIC_CORE_H) insn-config.h $(RECOG_H) $(FLAGS_H) $(OBSTACK_H)
$(BASIC_BLOCK_H) \
output.h $(DF_H) alloc-pool.h $(TIMEVAR_H) $(TREE_PASS_H) $(TARGET_H) \
Jakub
