/* Web construction code for GNU compiler.
Contributed by Jan Hubicka.
- Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2004, 2006, 2007, 2008, 2010
+ Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 2, or (at your option) any later
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* Simple optimization pass that splits independent uses of each pseudo,
increasing effectiveness of other optimizations. The optimization can
is almost unusable.
TODO
- - Add code to keep debugging up-to-date after splitting user variable
- pseudos. This can be done by keeping track of all the pseudos used
- for the variable and using life analysis information before reload
- to determine which one is live and, in case more than one are live,
- choose the one with the latest definition.
-
- Other optimization passes can benefit from the infrastructure too.
-
- We may use profile information and ignore infrequent use for the
purpose of web unifying, inserting the compensation code later to
implement full induction variable expansion for loops (currently
#include "rtl.h"
#include "hard-reg-set.h"
#include "flags.h"
+#include "obstack.h"
#include "basic-block.h"
#include "output.h"
#include "df.h"
#include "function.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "timevar.h"
+#include "tree-pass.h"
-/* This entry is allocated for each reference in the insn stream. */
-struct web_entry
-{
- /* Pointer to the parent in the union/find tree. */
- struct web_entry *pred;
- /* Newly assigned register to the entry. Set only for roots. */
- 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 *, char *);
-static void replace_ref (struct ref *, rtx);
-static int mark_addressof (rtx *, void *);
-
/* Find the root of unionfind tree (the representative of set). */
-static struct web_entry *
+struct web_entry *
unionfind_root (struct web_entry *element)
{
struct web_entry *element1 = element, *element2;
return element;
}
-/* Union sets. */
+/* Union sets.
+ Return true if FIRST and SECOND points to the same web entry structure and
+ nothing is done. Otherwise, return false. */
-static void
+bool
unionfind_union (struct web_entry *first, struct web_entry *second)
{
first = unionfind_root (first);
second = unionfind_root (second);
if (first == second)
- return;
+ return true;
second->pred = first;
+ return false;
}
-/* For each use, all possible defs reaching it must come in the same
- register, union them. */
+/* For INSN, union all defs and uses that are linked by match_dup.
+ FUN is the function that does the union. */
static void
-union_defs (struct df *df, struct ref *use, struct web_entry *def_entry,
- struct web_entry *use_entry)
+union_match_dups (rtx insn, struct web_entry *def_entry,
+ struct web_entry *use_entry,
+ bool (*fun) (struct web_entry *, struct web_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);
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+ df_ref *use_link = DF_INSN_INFO_USES (insn_info);
+ df_ref *def_link = DF_INSN_INFO_DEFS (insn_info);
+ int i;
+
+ extract_insn (insn);
+
+ for (i = 0; i < recog_data.n_dups; i++)
+ {
+ int op = recog_data.dup_num[i];
+ enum op_type type = recog_data.operand_type[op];
+ df_ref *ref, *dupref;
+ struct web_entry *entry;
+
+ for (dupref = use_link; *dupref; dupref++)
+ if (DF_REF_LOC (*dupref) == recog_data.dup_loc[i])
+ break;
+
+ if (*dupref == NULL
+ || DF_REF_REGNO (*dupref) < FIRST_PSEUDO_REGISTER)
+ continue;
+
+ ref = type == OP_IN ? use_link : def_link;
+ entry = type == OP_IN ? use_entry : def_entry;
+ for (; *ref; ref++)
+ if (DF_REF_LOC (*ref) == recog_data.operand_loc[op])
+ break;
+
+ (*fun) (use_entry + DF_REF_ID (*dupref), entry + DF_REF_ID (*ref));
+ }
+}
+
+/* For each use, all possible defs reaching it must come in the same
+ register, union them.
+ FUN is the function that does the union.
- /* Some instructions may use match_dup for their operands. In case the
- operands are dead, we will assign them different pseudos, creating
- invalid instructions, so union all uses of the same operand for each
- insn. */
+ In USED, we keep the DF_REF_ID of the first uninitialized uses of a
+ register, so that all uninitialized uses of the register can be
+ combined into a single web. We actually offset it by 2, because
+ the values 0 and 1 are reserved for use by entry_register. */
- while (use_link)
+void
+union_defs (df_ref use, struct web_entry *def_entry,
+ unsigned int *used, struct web_entry *use_entry,
+ bool (*fun) (struct web_entry *, struct web_entry *))
+{
+ struct df_insn_info *insn_info = DF_REF_INSN_INFO (use);
+ struct df_link *link = DF_REF_CHAIN (use);
+ df_ref *eq_use_link;
+ df_ref *def_link;
+ rtx set;
+
+ if (insn_info)
{
- 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;
+ rtx insn = insn_info->insn;
+ eq_use_link = DF_INSN_INFO_EQ_USES (insn_info);
+ def_link = DF_INSN_INFO_DEFS (insn_info);
+ set = single_set (insn);
+ }
+ else
+ {
+ /* An artificial use. It links up with nothing. */
+ eq_use_link = NULL;
+ def_link = NULL;
+ set = NULL;
}
- /* Recognize trivial noop moves and attempt to keep them as noop.
- While most of noop moves should be removed, we still keep some
- of them at libcall boundaries and such. */
+ /* Union all occurrences of the same register in reg notes. */
+
+ if (eq_use_link)
+ while (*eq_use_link)
+ {
+ if (use != *eq_use_link
+ && DF_REF_REAL_REG (use) == DF_REF_REAL_REG (*eq_use_link))
+ (*fun) (use_entry + DF_REF_ID (use),
+ use_entry + DF_REF_ID (*eq_use_link));
+ eq_use_link++;
+ }
+
+ /* Recognize trivial noop moves and attempt to keep them as noop. */
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;
- }
+ if (def_link)
+ while (*def_link)
+ {
+ if (DF_REF_REAL_REG (use) == DF_REF_REAL_REG (*def_link))
+ (*fun) (use_entry + DF_REF_ID (use),
+ def_entry + DF_REF_ID (*def_link));
+ def_link++;
+ }
}
+
+ /* UD chains of uninitialized REGs are empty. Keeping all uses of
+ the same uninitialized REG in a single web is not necessary for
+ correctness, since the uses are undefined, but it's wasteful to
+ allocate one register or slot for each reference. Furthermore,
+ creating new pseudos for uninitialized references in debug insns
+ (see PR 42631) causes -fcompare-debug failures. We record the
+ number of the first uninitialized reference we found, and merge
+ with it any other uninitialized references to the same
+ register. */
+ if (!link)
+ {
+ int regno = REGNO (DF_REF_REAL_REG (use));
+ if (used[regno])
+ (*fun) (use_entry + DF_REF_ID (use), use_entry + used[regno] - 2);
+ else
+ used[regno] = DF_REF_ID (use) + 2;
+ }
+
while (link)
{
- unionfind_union (use_entry + DF_REF_ID (use),
- def_entry + DF_REF_ID (link->ref));
+ (*fun) (use_entry + DF_REF_ID (use),
+ def_entry + DF_REF_ID (link->ref));
link = link->next;
}
/* A READ_WRITE use requires the corresponding def to be in the same
register. Find it and union. */
- if (use->flags & DF_REF_READ_WRITE)
+ if (DF_REF_FLAGS (use) & 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;
- }
+ df_ref *link;
+
+ if (insn_info)
+ link = DF_INSN_INFO_DEFS (insn_info);
+ else
+ link = NULL;
+
+ if (link)
+ while (*link)
+ {
+ if (DF_REF_REAL_REG (*link) == DF_REF_REAL_REG (use))
+ (*fun) (use_entry + DF_REF_ID (use),
+ def_entry + DF_REF_ID (*link));
+ link++;
+ }
}
}
/* Find the corresponding register for the given entry. */
static rtx
-entry_register (struct web_entry *entry, struct ref *ref, char *used,
- char *use_addressof)
+entry_register (struct web_entry *entry, df_ref ref, unsigned int *used)
{
struct web_entry *root;
rtx reg, newreg;
/* We are seeing this web for the first time, do the assignment. */
reg = DF_REF_REAL_REG (ref);
- /* In case the original register is already assigned, generate new one. */
- if (!used[REGNO (reg)])
+ /* In case the original register is already assigned, generate new
+ one. Since we use USED to merge uninitialized refs into a single
+ web, we might found an element to be nonzero without our having
+ used it. Test for 1, because union_defs saves it for our use,
+ and there won't be any use for the other values when we get to
+ this point. */
+ if (used[REGNO (reg)] != 1)
newreg = reg, used[REGNO (reg)] = 1;
- else if (REG_USERVAR_P (reg) && 0/*&& !flag_messy_debugging*/)
- {
- newreg = reg;
- if (dump_file)
- fprintf (dump_file,
- "New web forced to keep reg=%i (user variable)\n",
- REGNO (reg));
- }
- else if (use_addressof [REGNO (reg)])
- {
- newreg = reg;
- if (dump_file)
- fprintf (dump_file,
- "New web forced to keep reg=%i (address taken)\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);
- RTX_UNCHANGING_P (newreg) = RTX_UNCHANGING_P (reg);
REG_ATTRS (newreg) = REG_ATTRS (reg);
if (dump_file)
fprintf (dump_file, "Web oldreg=%i newreg=%i\n", REGNO (reg),
/* Replace the reference by REG. */
static void
-replace_ref (struct ref *ref, rtx reg)
+replace_ref (df_ref ref, rtx reg)
{
rtx oldreg = DF_REF_REAL_REG (ref);
rtx *loc = DF_REF_REAL_LOC (ref);
+ unsigned int uid = DF_REF_INSN_UID (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));
+ uid, REGNO (oldreg), REGNO (reg));
*loc = reg;
+ df_insn_rescan (DF_REF_INSN (ref));
}
-/* Mark each pseudo whose address is taken. */
-
-static int
-mark_addressof (rtx *rtl, void *data)
+\f
+static bool
+gate_handle_web (void)
{
- if (!*rtl)
- return 0;
- if (GET_CODE (*rtl) == ADDRESSOF
- && REG_P (XEXP (*rtl, 0)))
- ((char *)data)[REGNO (XEXP (*rtl, 0))] = 1;
- return 0;
+ return (optimize > 0 && flag_web);
}
/* Main entry point. */
-void
+static unsigned int
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;
- char *use_addressof;
+ unsigned int max = max_reg_num ();
+ unsigned int *used;
basic_block bb;
+ unsigned int uses_num = 0;
rtx insn;
- df = df_init ();
- df_analyze (df, 0, DF_UD_CHAIN | DF_EQUIV_NOTES);
+ df_set_flags (DF_NO_HARD_REGS + DF_EQ_NOTES);
+ df_chain_add_problem (DF_UD_CHAIN);
+ df_analyze ();
+ df_set_flags (DF_DEFER_INSN_RESCAN);
- 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));
- use_addressof = xcalloc (max, sizeof (char));
+ /* Assign ids to the uses. */
+ FOR_ALL_BB (bb)
+ FOR_BB_INSNS (bb, insn)
+ {
+ unsigned int uid = INSN_UID (insn);
+ if (NONDEBUG_INSN_P (insn))
+ {
+ df_ref *use_rec;
+ for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ DF_REF_ID (use) = uses_num++;
+ }
+ for (use_rec = DF_INSN_UID_EQ_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ DF_REF_ID (use) = uses_num++;
+ }
+ }
+ }
- if (dump_file)
- df_dump (df, DF_UD_CHAIN | DF_DU_CHAIN, dump_file);
+ /* Record the number of uses and defs at the beginning of the optimization. */
+ def_entry = XCNEWVEC (struct web_entry, DF_DEFS_TABLE_SIZE());
+ used = XCNEWVEC (unsigned, max);
+ use_entry = XCNEWVEC (struct web_entry, uses_num);
/* Produce the web. */
- for (i = 0; i < df->n_uses; i++)
- union_defs (df, df->uses[i], def_entry, use_entry);
-
- /* We can not safely rename registers whose address is taken. */
- FOR_EACH_BB (bb)
+ FOR_ALL_BB (bb)
FOR_BB_INSNS (bb, insn)
- {
- if (INSN_P (insn))
- for_each_rtx (&PATTERN (insn), mark_addressof, use_addressof);
- }
+ {
+ unsigned int uid = INSN_UID (insn);
+ if (NONDEBUG_INSN_P (insn))
+ {
+ df_ref *use_rec;
+ union_match_dups (insn, def_entry, use_entry, unionfind_union);
+ for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ union_defs (use, def_entry, used, use_entry, unionfind_union);
+ }
+ for (use_rec = DF_INSN_UID_EQ_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ union_defs (use, def_entry, used, use_entry, unionfind_union);
+ }
+ }
+ }
/* Update the instruction stream, allocating new registers for split pseudos
in progress. */
- for (i = 0; i < df->n_uses; i++)
- replace_ref (df->uses[i], entry_register (use_entry + i, df->uses[i],
- used, use_addressof));
- for (i = 0; i < df->n_defs; i++)
- replace_ref (df->defs[i], entry_register (def_entry + i, df->defs[i],
- used, use_addressof));
-
- /* Dataflow information is corrupt here, but it can be easily updated
- by creating new entries for new registers and updates or calling
- df_insns_modify. */
+ FOR_ALL_BB (bb)
+ FOR_BB_INSNS (bb, insn)
+ {
+ unsigned int uid = INSN_UID (insn);
+ if (NONDEBUG_INSN_P (insn))
+ {
+ df_ref *use_rec;
+ df_ref *def_rec;
+ for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ replace_ref (use, entry_register (use_entry + DF_REF_ID (use), use, used));
+ }
+ for (use_rec = DF_INSN_UID_EQ_USES (uid); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER)
+ replace_ref (use, entry_register (use_entry + DF_REF_ID (use), use, used));
+ }
+ for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ if (DF_REF_REGNO (def) >= FIRST_PSEUDO_REGISTER)
+ replace_ref (def, entry_register (def_entry + DF_REF_ID (def), def, used));
+ }
+ }
+ }
+
free (def_entry);
free (use_entry);
free (used);
- free (use_addressof);
- df_finish (df);
+ return 0;
}
+\f
+struct rtl_opt_pass pass_web =
+{
+ {
+ RTL_PASS,
+ "web", /* name */
+ gate_handle_web, /* gate */
+ web_main, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_WEB, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_dump_func /* todo_flags_finish */
+ }
+};
+
OSDN Git Service
