#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "toplev.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "flags.h"
#include "basic-block.h"
#include "output.h"
#include "df.h"
#include "function.h"
struct web_entry
{
struct web_entry *pred;
rtx reg;
};
static struct web_entry *unionfind_root (struct web_entry *);
static void unionfind_union (struct web_entry *, struct web_entry *);
static void union_defs (struct df *, struct ref *, struct web_entry *,
struct web_entry *);
static rtx entry_register (struct web_entry *, struct ref *, char *);
static void replace_ref (struct ref *, rtx);
static struct web_entry *
unionfind_root (struct web_entry *element)
{
struct web_entry *element1 = element, *element2;
while (element->pred)
element = element->pred;
while (element1->pred)
{
element2 = element1->pred;
element1->pred = element;
element1 = element2;
}
return element;
}
static void
unionfind_union (struct web_entry *first, struct web_entry *second)
{
first = unionfind_root (first);
second = unionfind_root (second);
if (first == second)
return;
second->pred = first;
}
static void
union_defs (struct df *df, struct ref *use, struct web_entry *def_entry,
struct web_entry *use_entry)
{
rtx insn = DF_REF_INSN (use);
struct df_link *link = DF_REF_CHAIN (use);
struct df_link *use_link = DF_INSN_USES (df, insn);
struct df_link *def_link = DF_INSN_DEFS (df, insn);
rtx set = single_set (insn);
while (use_link)
{
if (use != use_link->ref
&& DF_REF_REAL_REG (use) == DF_REF_REAL_REG (use_link->ref))
unionfind_union (use_entry + DF_REF_ID (use),
use_entry + DF_REF_ID (use_link->ref));
use_link = use_link->next;
}
if (set
&& SET_SRC (set) == DF_REF_REG (use)
&& SET_SRC (set) == SET_DEST (set))
{
while (def_link)
{
if (DF_REF_REAL_REG (use) == DF_REF_REAL_REG (def_link->ref))
unionfind_union (use_entry + DF_REF_ID (use),
def_entry + DF_REF_ID (def_link->ref));
def_link = def_link->next;
}
}
while (link)
{
unionfind_union (use_entry + DF_REF_ID (use),
def_entry + DF_REF_ID (link->ref));
link = link->next;
}
if (use->flags & DF_REF_READ_WRITE)
{
struct df_link *link = DF_INSN_DEFS (df, DF_REF_INSN (use));
while (link)
{
if (DF_REF_REAL_REG (link->ref) == DF_REF_REAL_REG (use))
unionfind_union (use_entry + DF_REF_ID (use),
def_entry + DF_REF_ID (link->ref));
link = link->next;
}
}
}
static rtx
entry_register (struct web_entry *entry, struct ref *ref, char *used)
{
struct web_entry *root;
rtx reg, newreg;
root = unionfind_root (entry);
if (root->reg)
return root->reg;
reg = DF_REF_REAL_REG (ref);
if (!used[REGNO (reg)])
newreg = reg, used[REGNO (reg)] = 1;
else if (REG_USERVAR_P (reg) && 0)
{
newreg = reg;
if (dump_file)
fprintf (dump_file,
"New web forced to keep reg=%i (user variable)\n",
REGNO (reg));
}
else
{
newreg = gen_reg_rtx (GET_MODE (reg));
REG_USERVAR_P (newreg) = REG_USERVAR_P (reg);
REG_POINTER (newreg) = REG_POINTER (reg);
REG_LOOP_TEST_P (newreg) = REG_LOOP_TEST_P (reg);
REG_ATTRS (newreg) = REG_ATTRS (reg);
if (dump_file)
fprintf (dump_file, "Web oldreg=%i newreg=%i\n", REGNO (reg),
REGNO (newreg));
}
root->reg = newreg;
return newreg;
}
static void
replace_ref (struct ref *ref, rtx reg)
{
rtx oldreg = DF_REF_REAL_REG (ref);
rtx *loc = DF_REF_REAL_LOC (ref);
if (oldreg == reg)
return;
if (dump_file)
fprintf (dump_file, "Updating insn %i (%i->%i)\n",
INSN_UID (DF_REF_INSN (ref)), REGNO (oldreg), REGNO (reg));
*loc = reg;
}
void
web_main (void)
{
struct df *df;
struct web_entry *def_entry;
struct web_entry *use_entry;
unsigned int i;
int max = max_reg_num ();
char *used;
df = df_init ();
df_analyze (df, 0, DF_UD_CHAIN | DF_EQUIV_NOTES);
def_entry = xcalloc (df->n_defs, sizeof (struct web_entry));
use_entry = xcalloc (df->n_uses, sizeof (struct web_entry));
used = xcalloc (max, sizeof (char));
if (dump_file)
df_dump (df, DF_UD_CHAIN | DF_DU_CHAIN, dump_file);
for (i = 0; i < df->n_uses; i++)
union_defs (df, df->uses[i], def_entry, use_entry);
for (i = 0; i < df->n_uses; i++)
replace_ref (df->uses[i], entry_register (use_entry + i, df->uses[i],
used));
for (i = 0; i < df->n_defs; i++)
replace_ref (df->defs[i], entry_register (def_entry + i, df->defs[i],
used));
free (def_entry);
free (use_entry);
free (used);
df_finish (df);
}