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[PATCH] Refactoring FSM bits into their own file 

[PATCH] Refactoring FSM bits into their own file
	* tree-ssa-threadedge.c (fsm_find_thread_path): Moved from here into
	tree-ssa-threadbackward.c.
	(fsm_find_control_statement_thread_paths): Likewise.
	(thread_through_normal_block): Break out FSM bits and move them
	into a new function in tree-ssa-threadbackward.c.  Call new function
	instead.
	Minimize header file usage.
	* tree-ssa-threadbackward.h: New file.
	* tree-ssa-threadbackward.c: Likewise.
	* Makefile.in (OBJS): Add tree-ssa-threadbackward.o

From-SVN: r228700
This commit is contained in:
Jeff Law 2015-10-11 19:17:51 -06:00 committed by Jeff Law
parent f29dc665c7
commit 0732f75fce
5 changed files with 366 additions and 291 deletions
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13
gcc/ChangeLog
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@ -1,3 +1,16 @@
2015-10-11 Jeff Law <law@redhat.com>
* tree-ssa-threadedge.c (fsm_find_thread_path): Moved from here into
tree-ssa-threadbackward.c.
(fsm_find_control_statement_thread_paths): Likewise.
(thread_through_normal_block): Break out FSM bits and move them
into a new function in tree-ssa-threadbackward.c. Call new function
instead.
Minimize header file usage.
* tree-ssa-threadbackward.h: New file.
* tree-ssa-threadbackward.c: Likewise.
* Makefile.in (OBJS): Add tree-ssa-threadbackward.o
2015-10-11 Uros Bizjak <ubizjak@gmail.com>
* config/alpha/alpha.h (ALPHA_ROUND): Implement using ROUND_UP macro.

1
gcc/Makefile.in
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@ -1478,6 +1478,7 @@ OBJS = \
tree-ssa-structalias.o \
tree-ssa-tail-merge.o \
tree-ssa-ter.o \
tree-ssa-threadbackward.o \
tree-ssa-threadedge.o \
tree-ssa-threadupdate.o \
tree-ssa-uncprop.o \

325
gcc/tree-ssa-threadbackward.c Normal file
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@ -0,0 +1,325 @@
/* SSA Jump Threading
Copyright (C) 2005-2015 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 3, 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 COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "predict.h"
#include "tree.h"
#include "gimple.h"
#include "fold-const.h"
#include "cfgloop.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
#include "tree-ssa-threadupdate.h"
#include "params.h"
#include "tree-ssa-loop.h"
#include "cfganal.h"
#include "tree-pass.h"
static int max_threaded_paths;
/* Return true if the CFG contains at least one path from START_BB to END_BB.
When a path is found, record in PATH the blocks from END_BB to START_BB.
VISITED_BBS is used to make sure we don't fall into an infinite loop. Bound
the recursion to basic blocks belonging to LOOP. */
static bool
fsm_find_thread_path (basic_block start_bb, basic_block end_bb,
vec<basic_block, va_gc> *&path,
hash_set<basic_block> *visited_bbs, loop_p loop)
{
if (loop != start_bb->loop_father)
return false;
if (start_bb == end_bb)
{
vec_safe_push (path, start_bb);
return true;
}
if (!visited_bbs->add (start_bb))
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, start_bb->succs)
if (fsm_find_thread_path (e->dest, end_bb, path, visited_bbs, loop))
{
vec_safe_push (path, start_bb);
return true;
}
}
return false;
}
/* We trace the value of the variable EXPR back through any phi nodes looking
for places where it gets a constant value and save the path. Stop after
having recorded MAX_PATHS jump threading paths. */
static void
fsm_find_control_statement_thread_paths (tree expr,
hash_set<basic_block> *visited_bbs,
vec<basic_block, va_gc> *&path,
bool seen_loop_phi)
{
tree var = SSA_NAME_VAR (expr);
gimple *def_stmt = SSA_NAME_DEF_STMT (expr);
basic_block var_bb = gimple_bb (def_stmt);
if (var == NULL || var_bb == NULL)
return;
/* For the moment we assume that an SSA chain only contains phi nodes, and
eventually one of the phi arguments will be an integer constant. In the
future, this could be extended to also handle simple assignments of
arithmetic operations. */
if (gimple_code (def_stmt) != GIMPLE_PHI)
return;
/* Avoid infinite recursion. */
if (visited_bbs->add (var_bb))
return;
gphi *phi = as_a <gphi *> (def_stmt);
int next_path_length = 0;
basic_block last_bb_in_path = path->last ();
if (loop_containing_stmt (phi)->header == gimple_bb (phi))
{
/* Do not walk through more than one loop PHI node. */
if (seen_loop_phi)
return;
seen_loop_phi = true;
}
/* Following the chain of SSA_NAME definitions, we jumped from a definition in
LAST_BB_IN_PATH to a definition in VAR_BB. When these basic blocks are
different, append to PATH the blocks from LAST_BB_IN_PATH to VAR_BB. */
if (var_bb != last_bb_in_path)
{
edge e;
int e_count = 0;
edge_iterator ei;
vec<basic_block, va_gc> *next_path;
vec_alloc (next_path, n_basic_blocks_for_fn (cfun));
FOR_EACH_EDGE (e, ei, last_bb_in_path->preds)
{
hash_set<basic_block> *visited_bbs = new hash_set<basic_block>;
if (fsm_find_thread_path (var_bb, e->src, next_path, visited_bbs,
e->src->loop_father))
++e_count;
delete visited_bbs;
/* If there is more than one path, stop. */
if (e_count > 1)
{
vec_free (next_path);
return;
}
}
/* Stop if we have not found a path: this could occur when the recursion
is stopped by one of the bounds. */
if (e_count == 0)
{
vec_free (next_path);
return;
}
/* Make sure we haven't already visited any of the nodes in
NEXT_PATH. Don't add them here to avoid pollution. */
for (unsigned int i = 0; i < next_path->length () - 1; i++)
{
if (visited_bbs->contains ((*next_path)[i]))
{
vec_free (next_path);
return;
}
}
/* Now add the nodes to VISISTED_BBS. */
for (unsigned int i = 0; i < next_path->length () - 1; i++)
visited_bbs->add ((*next_path)[i]);
/* Append all the nodes from NEXT_PATH to PATH. */
vec_safe_splice (path, next_path);
next_path_length = next_path->length ();
vec_free (next_path);
}
gcc_assert (path->last () == var_bb);
/* Iterate over the arguments of PHI. */
unsigned int i;
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = gimple_phi_arg_def (phi, i);
basic_block bbi = gimple_phi_arg_edge (phi, i)->src;
/* Skip edges pointing outside the current loop. */
if (!arg || var_bb->loop_father != bbi->loop_father)
continue;
if (TREE_CODE (arg) == SSA_NAME)
{
vec_safe_push (path, bbi);
/* Recursively follow SSA_NAMEs looking for a constant definition. */
fsm_find_control_statement_thread_paths (arg, visited_bbs, path,
seen_loop_phi);
path->pop ();
continue;
}
if (TREE_CODE (arg) != INTEGER_CST)
continue;
int path_length = path->length ();
/* A path with less than 2 basic blocks should not be jump-threaded. */
if (path_length < 2)
continue;
if (path_length > PARAM_VALUE (PARAM_MAX_FSM_THREAD_LENGTH))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of basic blocks on the path "
"exceeds PARAM_MAX_FSM_THREAD_LENGTH.\n");
continue;
}
if (max_threaded_paths <= 0)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of previously recorded FSM paths to thread "
"exceeds PARAM_MAX_FSM_THREAD_PATHS.\n");
continue;
}
/* Add BBI to the path. */
vec_safe_push (path, bbi);
++path_length;
int n_insns = 0;
gimple_stmt_iterator gsi;
int j;
loop_p loop = (*path)[0]->loop_father;
bool path_crosses_loops = false;
/* Count the number of instructions on the path: as these instructions
will have to be duplicated, we will not record the path if there are
too many instructions on the path. Also check that all the blocks in
the path belong to a single loop. */
for (j = 1; j < path_length - 1; j++)
{
basic_block bb = (*path)[j];
if (bb->loop_father != loop)
{
path_crosses_loops = true;
break;
}
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
/* Do not count empty statements and labels. */
if (gimple_code (stmt) != GIMPLE_NOP
&& gimple_code (stmt) != GIMPLE_LABEL
&& !is_gimple_debug (stmt))
++n_insns;
}
}
if (path_crosses_loops)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the path crosses loops.\n");
path->pop ();
continue;
}
if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of instructions on the path "
"exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
path->pop ();
continue;
}
vec<jump_thread_edge *> *jump_thread_path
= new vec<jump_thread_edge *> ();
/* Record the edges between the blocks in PATH. */
for (j = 0; j < path_length - 1; j++)
{
edge e = find_edge ((*path)[path_length - j - 1],
(*path)[path_length - j - 2]);
gcc_assert (e);
jump_thread_edge *x = new jump_thread_edge (e, EDGE_FSM_THREAD);
jump_thread_path->safe_push (x);
}
/* Add the edge taken when the control variable has value ARG. */
edge taken_edge = find_taken_edge ((*path)[0], arg);
jump_thread_edge *x
= new jump_thread_edge (taken_edge, EDGE_NO_COPY_SRC_BLOCK);
jump_thread_path->safe_push (x);
register_jump_thread (jump_thread_path);
--max_threaded_paths;
/* Remove BBI from the path. */
path->pop ();
}
/* Remove all the nodes that we added from NEXT_PATH. */
if (next_path_length)
vec_safe_truncate (path, (path->length () - next_path_length));
}
/* Search backwards from BB looking for paths where NAME (an SSA_NAME)
is a constant. Record such paths for jump threading.
It is assumed that BB ends with a control statement and that by
finding a path where NAME is a constant, we can thread the path. */
void
find_jump_threads_backwards (tree name, basic_block bb)
{
vec<basic_block, va_gc> *bb_path;
vec_alloc (bb_path, n_basic_blocks_for_fn (cfun));
vec_safe_push (bb_path, bb);
hash_set<basic_block> *visited_bbs = new hash_set<basic_block>;
max_threaded_paths = PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATHS);
fsm_find_control_statement_thread_paths (name, visited_bbs, bb_path, false);
delete visited_bbs;
vec_free (bb_path);
}

25
gcc/tree-ssa-threadbackward.h Normal file
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@ -0,0 +1,25 @@
/* Header file for SSA dominator optimizations.
Copyright (C) 2013-2015 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 3, 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 COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#ifndef GCC_TREE_SSA_THREADFSM_H
#define GCC_TREE_SSA_THREADFSM_H
extern void find_jump_threads_backwards (tree, basic_block);
#endif /* GCC_TREE_SSA_THREADFSM_H */

293
gcc/tree-ssa-threadedge.c
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@ -25,28 +25,18 @@ along with GCC; see the file COPYING3. If not see
#include "predict.h"
#include "tree.h"
#include "gimple.h"
#include "hard-reg-set.h"
#include "ssa.h"
#include "alias.h"
#include "fold-const.h"
#include "flags.h"
#include "tm_p.h"
#include "cfgloop.h"
#include "timevar.h"
#include "dumpfile.h"
#include "internal-fn.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
#include "tree-ssa-propagate.h"
#include "tree-ssa-threadupdate.h"
#include "langhooks.h"
#include "params.h"
#include "tree-ssa-scopedtables.h"
#include "tree-ssa-threadedge.h"
#include "tree-ssa-loop.h"
#include "tree-ssa-threadbackward.h"
#include "tree-ssa-dom.h"
#include "builtins.h"
#include "cfganal.h"
/* To avoid code explosion due to jump threading, we limit the
number of statements we are going to copy. This variable
@ -894,275 +884,6 @@ thread_around_empty_blocks (edge taken_edge,
return false;
}
/* Return true if the CFG contains at least one path from START_BB to END_BB.
When a path is found, record in PATH the blocks from END_BB to START_BB.
VISITED_BBS is used to make sure we don't fall into an infinite loop. Bound
the recursion to basic blocks belonging to LOOP. */
static bool
fsm_find_thread_path (basic_block start_bb, basic_block end_bb,
vec<basic_block, va_gc> *&path,
hash_set<basic_block> *visited_bbs, loop_p loop)
{
if (loop != start_bb->loop_father)
return false;
if (start_bb == end_bb)
{
vec_safe_push (path, start_bb);
return true;
}
if (!visited_bbs->add (start_bb))
{
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, start_bb->succs)
if (fsm_find_thread_path (e->dest, end_bb, path, visited_bbs, loop))
{
vec_safe_push (path, start_bb);
return true;
}
}
return false;
}
static int max_threaded_paths;
/* We trace the value of the variable EXPR back through any phi nodes looking
for places where it gets a constant value and save the path. Stop after
having recorded MAX_PATHS jump threading paths. */
static void
fsm_find_control_statement_thread_paths (tree expr,
hash_set<basic_block> *visited_bbs,
vec<basic_block, va_gc> *&path,
bool seen_loop_phi)
{
tree var = SSA_NAME_VAR (expr);
gimple *def_stmt = SSA_NAME_DEF_STMT (expr);
basic_block var_bb = gimple_bb (def_stmt);
if (var == NULL || var_bb == NULL)
return;
/* For the moment we assume that an SSA chain only contains phi nodes, and
eventually one of the phi arguments will be an integer constant. In the
future, this could be extended to also handle simple assignments of
arithmetic operations. */
if (gimple_code (def_stmt) != GIMPLE_PHI)
return;
/* Avoid infinite recursion. */
if (visited_bbs->add (var_bb))
return;
gphi *phi = as_a <gphi *> (def_stmt);
int next_path_length = 0;
basic_block last_bb_in_path = path->last ();
if (loop_containing_stmt (phi)->header == gimple_bb (phi))
{
/* Do not walk through more than one loop PHI node. */
if (seen_loop_phi)
return;
seen_loop_phi = true;
}
/* Following the chain of SSA_NAME definitions, we jumped from a definition in
LAST_BB_IN_PATH to a definition in VAR_BB. When these basic blocks are
different, append to PATH the blocks from LAST_BB_IN_PATH to VAR_BB. */
if (var_bb != last_bb_in_path)
{
edge e;
int e_count = 0;
edge_iterator ei;
vec<basic_block, va_gc> *next_path;
vec_alloc (next_path, n_basic_blocks_for_fn (cfun));
FOR_EACH_EDGE (e, ei, last_bb_in_path->preds)
{
hash_set<basic_block> *visited_bbs = new hash_set<basic_block>;
if (fsm_find_thread_path (var_bb, e->src, next_path, visited_bbs,
e->src->loop_father))
++e_count;
delete visited_bbs;
/* If there is more than one path, stop. */
if (e_count > 1)
{
vec_free (next_path);
return;
}
}
/* Stop if we have not found a path: this could occur when the recursion
is stopped by one of the bounds. */
if (e_count == 0)
{
vec_free (next_path);
return;
}
/* Make sure we haven't already visited any of the nodes in
NEXT_PATH. Don't add them here to avoid pollution. */
for (unsigned int i = 0; i < next_path->length () - 1; i++)
{
if (visited_bbs->contains ((*next_path)[i]))
{
vec_free (next_path);
return;
}
}
/* Now add the nodes to VISISTED_BBS. */
for (unsigned int i = 0; i < next_path->length () - 1; i++)
visited_bbs->add ((*next_path)[i]);
/* Append all the nodes from NEXT_PATH to PATH. */
vec_safe_splice (path, next_path);
next_path_length = next_path->length ();
vec_free (next_path);
}
gcc_assert (path->last () == var_bb);
/* Iterate over the arguments of PHI. */
unsigned int i;
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = gimple_phi_arg_def (phi, i);
basic_block bbi = gimple_phi_arg_edge (phi, i)->src;
/* Skip edges pointing outside the current loop. */
if (!arg || var_bb->loop_father != bbi->loop_father)
continue;
if (TREE_CODE (arg) == SSA_NAME)
{
vec_safe_push (path, bbi);
/* Recursively follow SSA_NAMEs looking for a constant definition. */
fsm_find_control_statement_thread_paths (arg, visited_bbs, path,
seen_loop_phi);
path->pop ();
continue;
}
if (TREE_CODE (arg) != INTEGER_CST)
continue;
int path_length = path->length ();
/* A path with less than 2 basic blocks should not be jump-threaded. */
if (path_length < 2)
continue;
if (path_length > PARAM_VALUE (PARAM_MAX_FSM_THREAD_LENGTH))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of basic blocks on the path "
"exceeds PARAM_MAX_FSM_THREAD_LENGTH.\n");
continue;
}
if (max_threaded_paths <= 0)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of previously recorded FSM paths to thread "
"exceeds PARAM_MAX_FSM_THREAD_PATHS.\n");
continue;
}
/* Add BBI to the path. */
vec_safe_push (path, bbi);
++path_length;
int n_insns = 0;
gimple_stmt_iterator gsi;
int j;
loop_p loop = (*path)[0]->loop_father;
bool path_crosses_loops = false;
/* Count the number of instructions on the path: as these instructions
will have to be duplicated, we will not record the path if there are
too many instructions on the path. Also check that all the blocks in
the path belong to a single loop. */
for (j = 1; j < path_length - 1; j++)
{
basic_block bb = (*path)[j];
if (bb->loop_father != loop)
{
path_crosses_loops = true;
break;
}
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
/* Do not count empty statements and labels. */
if (gimple_code (stmt) != GIMPLE_NOP
&& gimple_code (stmt) != GIMPLE_LABEL
&& !is_gimple_debug (stmt))
++n_insns;
}
}
if (path_crosses_loops)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the path crosses loops.\n");
path->pop ();
continue;
}
if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "FSM jump-thread path not considered: "
"the number of instructions on the path "
"exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
path->pop ();
continue;
}
vec<jump_thread_edge *> *jump_thread_path
= new vec<jump_thread_edge *> ();
/* Record the edges between the blocks in PATH. */
for (j = 0; j < path_length - 1; j++)
{
edge e = find_edge ((*path)[path_length - j - 1],
(*path)[path_length - j - 2]);
gcc_assert (e);
jump_thread_edge *x = new jump_thread_edge (e, EDGE_FSM_THREAD);
jump_thread_path->safe_push (x);
}
/* Add the edge taken when the control variable has value ARG. */
edge taken_edge = find_taken_edge ((*path)[0], arg);
jump_thread_edge *x
= new jump_thread_edge (taken_edge, EDGE_NO_COPY_SRC_BLOCK);
jump_thread_path->safe_push (x);
register_jump_thread (jump_thread_path);
--max_threaded_paths;
/* Remove BBI from the path. */
path->pop ();
}
/* Remove all the nodes that we added from NEXT_PATH. */
if (next_path_length)
vec_safe_truncate (path, (path->length () - next_path_length));
}
/* We are exiting E->src, see if E->dest ends with a conditional
jump which has a known value when reached via E.
@ -1333,17 +1054,7 @@ thread_through_normal_block (edge e,
/* When COND cannot be simplified, try to find paths from a control
statement back through the PHI nodes which would affect that control
statement. */
vec<basic_block, va_gc> *bb_path;
vec_alloc (bb_path, n_basic_blocks_for_fn (cfun));
vec_safe_push (bb_path, e->dest);
hash_set<basic_block> *visited_bbs = new hash_set<basic_block>;
max_threaded_paths = PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATHS);
fsm_find_control_statement_thread_paths (cond, visited_bbs, bb_path,
false);
delete visited_bbs;
vec_free (bb_path);
find_jump_threads_backwards (cond, e->dest);
}
return 0;
}