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Commit 4ec6eeb8 authored by Michael Beck's avatar Michael Beck
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make the Load/Store Optimization more greedy: if a Load or Store is removed, 

reduce, a previous Load serving the address might get unused. Remove it.

[r7880]
parent 017f0dbc
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Inline Side-by-side
ir/opt/ldstopt.c
View file @ 4ec6eeb8
......@@ -22,22 +22,22 @@
# include <string.h>
#endif
# include "irnode_t.h"
# include "irgraph_t.h"
# include "irmode_t.h"
# include "iropt_t.h"
# include "ircons_t.h"
# include "irgmod.h"
# include "irgwalk.h"
# include "irvrfy.h"
# include "tv_t.h"
# include "dbginfo_t.h"
# include "iropt_dbg.h"
# include "irflag_t.h"
# include "array.h"
# include "irhooks.h"
# include "irtools.h"
# include "opt_polymorphy.h"
#include "irnode_t.h"
#include "irgraph_t.h"
#include "irmode_t.h"
#include "iropt_t.h"
#include "ircons_t.h"
#include "irgmod.h"
#include "irgwalk.h"
#include "irvrfy.h"
#include "tv_t.h"
#include "dbginfo_t.h"
#include "iropt_dbg.h"
#include "irflag_t.h"
#include "array.h"
#include "irhooks.h"
#include "irtools.h"
#include "opt_polymorphy.h"
#ifdef DO_CACHEOPT
#include "cacheopt/cachesim.h"
......@@ -57,7 +57,7 @@ enum changes_t {
* walker environment
*/
typedef struct _walk_env_t {
struct obstack obst; /**< list of all stores */
struct obstack obst; /**< list of all stores */
unsigned changes; /**< a bitmask of graph changes */
} walk_env_t;
......@@ -68,9 +68,7 @@ enum ldst_flags_t {
LDST_VISITED = 1 /**< if set, this Load/Store is already visited */
};
/**
* a Load/Store info
*/
/** A Load/Store info. */
typedef struct _ldst_info_t {
ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */
ir_node *exc_block; /**< the exception block if available */
......@@ -80,7 +78,7 @@ typedef struct _ldst_info_t {
} ldst_info_t;
/**
* flags for control flow
* flags for control flow.
*/
enum block_flags_t {
BLOCK_HAS_COND = 1, /**< Block has conditional control flow */
......@@ -88,7 +86,7 @@ enum block_flags_t {
};
/**
* a Block info
* a Block info.
*/
typedef struct _block_info_t {
unsigned flags; /**< flags for the block */
......@@ -104,8 +102,7 @@ static unsigned master_visited = 0;
/**
* get the Load/Store info of a node
*/
static ldst_info_t *get_ldst_info(ir_node *node, walk_env_t *env)
{
static ldst_info_t *get_ldst_info(ir_node *node, walk_env_t *env) {
ldst_info_t *info = get_irn_link(node);
if (! info) {
......@@ -171,8 +168,10 @@ static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos)
return 0;
}
#define get_irn_out_n(node) (unsigned)PTR_TO_INT(get_irn_link(node))
#define set_irn_out_n(node, n) set_irn_link(adr, INT_TO_PTR(n))
/** Return the number of uses of an address node */
#define get_irn_n_uses(adr) (unsigned)PTR_TO_INT(get_irn_link(adr))
/** Sets the number of uses of an address node */
#define set_irn_n_uses(adr, n) set_irn_link(adr, INT_TO_PTR(n))
/**
* walker, collects all Load/Store/Proj nodes
......@@ -200,7 +199,7 @@ static void collect_nodes(ir_node *node, void *env)
if ((ldst_info->flags & LDST_VISITED) == 0) {
adr = get_Load_ptr(pred);
set_irn_out_n(adr, get_irn_out_n(adr) + 1);
set_irn_n_uses(adr, get_irn_n_uses(adr) + 1);
ldst_info->flags |= LDST_VISITED;
}
......@@ -225,7 +224,7 @@ static void collect_nodes(ir_node *node, void *env)
if ((ldst_info->flags & LDST_VISITED) == 0) {
adr = get_Store_ptr(pred);
set_irn_out_n(adr, get_irn_out_n(adr) + 1);
set_irn_n_uses(adr, get_irn_n_uses(adr) + 1);
ldst_info->flags |= LDST_VISITED;
}
......@@ -394,6 +393,56 @@ static compound_graph_path *get_accessed_path(ir_node *ptr) {
return rec_get_accessed_path(ptr, 0);
}
/* forward */
static void reduce_adr_usage(ir_node *ptr);
/**
* Update a Load that may lost it's usage.
*/
static void handle_load_update(ir_node *load) {
ldst_info_t *info = get_irn_link(load);
/* do NOT touch volatile loads for now */
if (get_Load_volatility(load) == volatility_is_volatile)
return;
if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) {
ir_node *ptr = get_Load_ptr(load);
ir_node *mem = get_Load_mem(load);
/* a Load which value is neither used nor exception checked, remove it */
exchange(info->projs[pn_Load_M], mem);
reduce_adr_usage(ptr);
}
}
/**
* A Use of an address node is vanished. Check if this was a Proj
* node and update the counters.
*/
static void reduce_adr_usage(ir_node *ptr) {
int use_count = get_irn_n_uses(ptr);
--use_count;
assert(use_count >= 0);
set_irn_n_uses(ptr, use_count);
if (is_Proj(ptr)) {
if (use_count <= 0) {
/* this Proj is now dead, update the Load/Store info */
ir_node *pred = get_Proj_pred(ptr);
opcode code = get_irn_opcode(pred);
if (code == iro_Load) {
ldst_info_t *info = get_irn_link(pred);
info->projs[get_Proj_proj(ptr)] = NULL;
/* this node lost it's result proj, handle that */
handle_load_update(pred);
}
}
}
}
/**
* Follow the memory chain as long as there are only Loads
* and try to replace current Load or Store by a previous one.
......@@ -452,6 +501,7 @@ static unsigned follow_Load_chain(ir_node *load, ir_node *curr) {
if (info->projs[pn_Load_res])
exchange(info->projs[pn_Load_res], value);
reduce_adr_usage(ptr);
return res | DF_CHANGED;
}
}
......@@ -496,6 +546,7 @@ static unsigned follow_Load_chain(ir_node *load, ir_node *curr) {
res |= CF_CHANGED;
}
reduce_adr_usage(ptr);
return res |= DF_CHANGED;
}
}
......@@ -590,6 +641,7 @@ static unsigned optimize_load(ir_node *load)
/* a Load which value is neither used nor exception checked, remove it */
exchange(info->projs[pn_Load_M], mem);
reduce_adr_usage(ptr);
return res | DF_CHANGED;
}
......@@ -607,6 +659,8 @@ static unsigned optimize_load(ir_node *load)
}
if (info->projs[pn_Load_res])
exchange(info->projs[pn_Load_res], new_node);
reduce_adr_usage(ptr);
return res | DF_CHANGED;
}
......@@ -640,7 +694,6 @@ static unsigned optimize_load(ir_node *load)
exchange(info->projs[pn_Load_M], mem);
res |= DF_CHANGED;
}
/* no result :-) */
if (info->projs[pn_Load_res]) {
if (is_atomic_entity(ent)) {
......@@ -648,9 +701,11 @@ static unsigned optimize_load(ir_node *load)
DBG_OPT_RC(load, c);
exchange(info->projs[pn_Load_res], c);
return DF_CHANGED | res;
res |= DF_CHANGED;
}
}
reduce_adr_usage(ptr);
return res;
}
else if (variability_constant == get_entity_variability(ent)) {
compound_graph_path *path = get_accessed_path(ptr);
......@@ -683,8 +738,10 @@ static unsigned optimize_load(ir_node *load)
}
if (info->projs[pn_Load_res]) {
exchange(info->projs[pn_Load_res], copy_const_value(get_irn_dbg_info(load), c));
return res | DF_CHANGED;
res |= DF_CHANGED;
}
reduce_adr_usage(ptr);
return res;
}
else {
/* We can not determine a correct access path. E.g., in jack, we load
......@@ -702,7 +759,7 @@ static unsigned optimize_load(ir_node *load)
/* Check, if the address of this load is used more than once.
* If not, this load cannot be removed in any case. */
if (get_irn_out_n(ptr) <= 1)
if (get_irn_n_uses(ptr) <= 1)
return res;
/*
......@@ -752,6 +809,7 @@ static unsigned follow_Load_chain_for_Store(ir_node *store, ir_node *curr) {
if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) {
DBG_OPT_WAW(pred, store);
exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) );
reduce_adr_usage(ptr);
return DF_CHANGED;
}
}
......@@ -764,6 +822,7 @@ static unsigned follow_Load_chain_for_Store(ir_node *store, ir_node *curr) {
if (! info->projs[pn_Store_X_except]) {
DBG_OPT_WAR(store, pred);
exchange( info->projs[pn_Store_M], mem );
reduce_adr_usage(ptr);
return DF_CHANGED;
}
}
......@@ -806,7 +865,7 @@ static unsigned optimize_store(ir_node *store)
/* Check, if the address of this load is used more than once.
* If not, this load cannot be removed in any case. */
if (get_irn_out_n(ptr) <= 1)
if (get_irn_n_uses(ptr) <= 1)
return 0;
mem = get_Store_mem(store);
......@@ -835,9 +894,8 @@ static unsigned optimize_store(ir_node *store)
*
* This is only possible if the predecessor blocks have only one successor.
*/
static unsigned optimize_phi(ir_node *phi, void *env)
static unsigned optimize_phi(ir_node *phi, walk_env_t *wenv)
{
walk_env_t *wenv = env;
int i, n;
ir_node *store, *old_store, *ptr, *block, *phiM, *phiD, *exc, *projM;
ir_mode *mode;
......@@ -930,6 +988,12 @@ static unsigned optimize_phi(ir_node *phi, void *env)
inM[i] = get_Store_mem(pred);
inD[i] = get_Store_value(pred);
idx[i] = info->exc_idx;
/* Should we here replace the Proj after the Store by
* the Store's memory? Would be save but should not be needed,
* because we checked that all pred blocks have only one
* control flow successor.
*/
}
block = get_nodes_block(phi);
......@@ -944,6 +1008,8 @@ static unsigned optimize_phi(ir_node *phi, void *env)
#ifdef DO_CACHEOPT
co_set_irn_name(store, co_get_irn_ident(old_store));
#endif
/* we replaced n uses by 1 */
set_irn_n_uses(ptr, get_irn_n_uses(ptr) - n + 1);
projM = new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M);
......@@ -993,7 +1059,7 @@ static void do_load_store_optimize(ir_node *n, void *env)
break;
case iro_Phi:
wenv->changes |= optimize_phi(n, env);
wenv->changes |= optimize_phi(n, wenv);
default:
;
......@@ -1007,6 +1073,10 @@ void optimize_load_store(ir_graph *irg)
{
walk_env_t env;
/* must set current it graph here, because new nodes are
constructed in the fixpoint iteration */
current_ir_graph = irg;
assert(get_irg_phase_state(irg) != phase_building);
assert(get_irg_pinned(irg) != op_pin_state_floats &&
"LoadStore optimization needs pinned graph");
......
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