DFI_bp,
DFI_ce1,
DFI_tracer,
+ DFI_web,
DFI_loop2,
DFI_cse2,
DFI_life,
Remaining -d letters:
" m q "
- " JK O Q V YZ"
+ " JK O Q V Y "
*/
static struct dump_file_info dump_file[DFI_MAX] =
{ "bp", 'b', 1, 0, 0 },
{ "ce1", 'C', 1, 0, 0 },
{ "tracer", 'T', 1, 0, 0 },
+ { "web", 'Z', 0, 0, 0 },
{ "loop2", 'L', 1, 0, 0 },
{ "cse2", 't', 1, 0, 0 },
{ "life", 'f', 1, 0, 0 }, /* Yes, duplicate enable switch. */
int flag_syntax_only = 0;
+/* Nonzero means performs web construction pass. */
+
+int flag_web;
+
/* Nonzero means perform loop optimizer. */
int flag_loop_optimize;
{"pcc-struct-return", &flag_pcc_struct_return, 1 },
{"reg-struct-return", &flag_pcc_struct_return, 0 },
{"delayed-branch", &flag_delayed_branch, 1 },
+ {"web", &flag_web, 1},
{"gcse", &flag_gcse, 1 },
{"gcse-lm", &flag_gcse_lm, 1 },
{"gcse-sm", &flag_gcse_sm, 1 },
timevar_pop (TV_IFCVT);
}
+static void
+rest_of_handle_web (tree decl, rtx insns)
+{
+ open_dump_file (DFI_web, decl);
+ timevar_push (TV_WEB);
+ web_main ();
+ delete_trivially_dead_insns (insns, max_reg_num ());
+ cleanup_cfg (CLEANUP_EXPENSIVE);
+
+ timevar_pop (TV_WEB);
+ close_dump_file (DFI_web, print_rtl_with_bb, insns);
+ reg_scan (get_insns (), max_reg_num (), 0);
+}
+
/* Do branch profiling and static profile estimation passes. */
static void
rest_of_handle_branch_prob (tree decl, rtx insns)
rest_of_handle_cfg (decl, insns);
+ if (flag_web)
+ rest_of_handle_web (decl, insns);
+
if (optimize > 0
|| profile_arc_flag || flag_test_coverage || flag_branch_probabilities)
rest_of_handle_branch_prob (decl, insns);
--- /dev/null
+/* Web construction code for GNU compiler.
+ Contributed by Jan Hubicka
+ Copyright (C) 2001, 2002 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
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+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. */
+
+/* Simple optimization pass that splits indepdendent uses of each pseudo
+ increasing effectivity of other optimizations. The optimization can
+ serve as an example of the use of dataflow module.
+
+ We don't split registers with REG_USERVAR set unless -fmessy-debugging is
+ used, because debug information about such split variables is almost
+ useless.
+
+ TODO
+ - Add code to keep debugging up-to-date after splitting of user variable
+ pseudos. This can be done by remembering all the pseudos used for the
+ variable and use life analysis information before reload to determing
+ wich one of the possible choices is alive and in case more are live,
+ choose one with latest definition.
+
+ Some other optimization passes will benefit from the infrastructure
+ too.
+
+ - We may use profile information and ignore infrequent use for purposes
+ of web unifying inserting the compensation code later to implement full
+ induction variable expansion for loops (currently we expand only if
+ induction is dead afterwards, that is often the case anyway). */
+
+#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"
+
+
+/* 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 PARAMS ((struct web_entry *));
+static void unionfind_union PARAMS ((struct web_entry *,
+ struct web_entry *));
+static void union_defs PARAMS ((struct df *, struct ref *,
+ struct web_entry *,
+ struct web_entry *));
+static rtx entry_register PARAMS ((struct web_entry *,
+ struct ref *, char *, char *));
+static void replace_ref PARAMS ((struct ref *, rtx));
+static int mark_addressof PARAMS ((rtx *, void *));
+
+/* Find the root of unionfind tree (the representatnt of set). */
+
+static struct web_entry *
+unionfind_root (element)
+ 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;
+}
+
+/* Union sets. */
+
+static void
+unionfind_union (first, second)
+ struct web_entry *first, *second;
+{
+ first = unionfind_root (first);
+ second = unionfind_root (second);
+ if (first == second)
+ return;
+ second->pred = first;
+}
+
+/* For each use, all possible defs reaching it must come in same register,
+ union them. */
+
+static void
+union_defs (df, use, def_entry, use_entry)
+ 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);
+
+ /* Some instructions may use match_dup for it's operands. In case the
+ operands are dead, we will assign them different pseudos creating
+ invalid instruction, so union all uses of the same operands for each
+ 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;
+ }
+
+ /* Recognize trivial noop moves and attempt to keep them noop.
+ While most of noop moves should be removed we still keep some at
+ libcall boundaries and such. */
+
+ 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;
+ }
+
+ /* An READ_WRITE use require the corresponding def to be in the same
+ register. Find it and union. */
+ if (use->flags & DF_REF_READ_WRITE)
+ {
+ struct df_link *link = DF_INSN_DEFS (df, DF_REF_INSN (use));
+
+ while (DF_REF_REAL_REG (link->ref) != DF_REF_REAL_REG (use))
+ link = link->next;
+
+ unionfind_union (use_entry + DF_REF_ID (use),
+ def_entry + DF_REF_ID (link->ref));
+ }
+}
+
+/* Find corresponding register for given entry. */
+
+static rtx
+entry_register (entry, ref, used, use_addressof)
+ struct web_entry *entry;
+ struct ref *ref;
+ char *used;
+ char *use_addressof;
+{
+ struct web_entry *root;
+ rtx reg, newreg;
+
+ /* Find corresponding web and see if it has been visited. */
+
+ root = unionfind_root (entry);
+ if (root->reg)
+ return root->reg;
+
+ /* We are seeing this web 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)])
+ newreg = reg, used[REGNO (reg)] = 1;
+ else if (REG_USERVAR_P (reg) && 0/*&& !flag_messy_debugging*/)
+ {
+ newreg = reg;
+ if (rtl_dump_file)
+ fprintf (rtl_dump_file,
+ "New web forced to keep reg=%i (user variable)\n",
+ REGNO (reg));
+ }
+ else if (use_addressof [REGNO (reg)])
+ {
+ newreg = reg;
+ if (rtl_dump_file)
+ fprintf (rtl_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 (rtl_dump_file)
+ fprintf (rtl_dump_file, "Web oldreg=%i newreg=%i\n", REGNO (reg),
+ REGNO (newreg));
+ }
+
+ root->reg = newreg;
+ return newreg;
+}
+
+/* Replace the reference by REG. */
+
+static void
+replace_ref (ref, reg)
+ struct ref *ref;
+ rtx reg;
+{
+ rtx oldreg = DF_REF_REAL_REG (ref);
+ rtx *loc = DF_REF_REAL_LOC (ref);
+
+ if (oldreg == reg)
+ return;
+ if (rtl_dump_file)
+ fprintf (rtl_dump_file, "Updating insn %i (%i->%i)\n",
+ INSN_UID (DF_REF_INSN (ref)), REGNO (oldreg), REGNO (reg));
+ *loc = reg;
+}
+
+/* Mark each pseudo, whose address is taken. */
+
+static int
+mark_addressof (rtl, data)
+ rtx *rtl;
+ void *data;
+{
+ if (!*rtl)
+ return 0;
+ if (GET_CODE (*rtl) == ADDRESSOF
+ && REG_P (XEXP (*rtl, 0)))
+ ((char *)data)[REGNO (XEXP (*rtl, 0))] = 1;
+ return 0;
+}
+
+/* Main entry point. */
+
+void
+web_main ()
+{
+ 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;
+ rtx insn;
+
+ df = df_init ();
+ df_analyse (df, 0, DF_UD_CHAIN | DF_EQUIV_NOTES);
+
+ def_entry =
+ (struct web_entry *) xcalloc (df->n_defs, sizeof (struct web_entry));
+ use_entry =
+ (struct web_entry *) xcalloc (df->n_uses, sizeof (struct web_entry));
+ used = (char *) xcalloc (max, sizeof (char));
+ use_addressof = (char *) xcalloc (max, sizeof (char));
+
+ if (rtl_dump_file)
+ df_dump (df, DF_UD_CHAIN | DF_DU_CHAIN, rtl_dump_file);
+
+ /* 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 (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ for_each_rtx (&PATTERN (insn), mark_addressof, use_addressof);
+
+ /* 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 easy to update it
+ by creating new entries for new registers and update or calilng
+ df_insns_modify. */
+ free (def_entry);
+ free (use_entry);
+ free (used);
+ free (use_addressof);
+ df_finish (df);
+}
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