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Makefile.in (OBJS-common): Add tree-ssa-phiprop.o

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2008-03-12  Richard Guenther  <rguenther@suse.de>

	* Makefile.in (OBJS-common): Add tree-ssa-phiprop.o
	(tree-ssa-phiprop.o): Copy dependencies from tree-ssa-forwprop.o.
	* timevar.def (TV_TREE_PHIPROP): Add.
	* tree-ssa-phiprop.c: Split from tree-ssa-forwprop.c, added
	pass description.  Use TV_TREE_PHIPROP.
	* tree-ssa-forwprop.c: Remove phiprop code.

From-SVN: r133140
This commit is contained in:
Richard Guenther 2008-03-12 12:15:41 +00:00 • committed by Richard Biener
parent cb31c4bcc5
commit 6751444978
5 changed files with 404 additions and 299 deletions
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9
gcc/ChangeLog
View file

@ -1,3 +1,12 @@
2008-03-12 Richard Guenther <rguenther@suse.de>
* Makefile.in (OBJS-common): Add tree-ssa-phiprop.o
(tree-ssa-phiprop.o): Copy dependencies from tree-ssa-forwprop.o.
* timevar.def (TV_TREE_PHIPROP): Add.
* tree-ssa-phiprop.c: Split from tree-ssa-forwprop.c, added
pass description. Use TV_TREE_PHIPROP.
* tree-ssa-forwprop.c: Remove phiprop code.
2008-03-12 Jakub Jelinek <jakub@redhat.com>
PR middle-end/35549

5
gcc/Makefile.in
View file

@ -1194,6 +1194,7 @@ OBJS-common = \
tree-ssa-math-opts.o \
tree-ssa-operands.o \
tree-ssa-phiopt.o \
tree-ssa-phiprop.o \
tree-ssa-pre.o \
tree-ssa-propagate.o \
tree-ssa-reassoc.o \
@ -2017,6 +2018,10 @@ tree-ssa-forwprop.o : tree-ssa-forwprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
$(TM_H) $(GGC_H) $(TREE_H) $(RTL_H) $(TM_P_H) $(BASIC_BLOCK_H) \
$(TREE_FLOW_H) tree-pass.h $(TREE_DUMP_H) $(DIAGNOSTIC_H) $(TIMEVAR_H) \
langhooks.h $(FLAGS_H)
tree-ssa-phiprop.o : tree-ssa-forwprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
$(TM_H) $(GGC_H) $(TREE_H) $(RTL_H) $(TM_P_H) $(BASIC_BLOCK_H) \
$(TREE_FLOW_H) tree-pass.h $(TREE_DUMP_H) $(DIAGNOSTIC_H) $(TIMEVAR_H) \
langhooks.h $(FLAGS_H)
tree-ssa-ifcombine.o : tree-ssa-ifcombine.c $(CONFIG_H) $(SYSTEM_H) \
coretypes.h $(TM_H) $(TREE_H) $(BASIC_BLOCK_H) \
$(TREE_FLOW_H) tree-pass.h $(TREE_DUMP_H) $(DIAGNOSTIC_H) $(TIMEVAR_H)

1
gcc/timevar.def
View file

@ -109,6 +109,7 @@ DEFTIMEVAR (TV_TREE_FRE , "tree FRE")
DEFTIMEVAR (TV_TREE_SINK , "tree code sinking")
DEFTIMEVAR (TV_TREE_PHIOPT , "tree linearize phis")
DEFTIMEVAR (TV_TREE_FORWPROP , "tree forward propagate")
DEFTIMEVAR (TV_TREE_PHIPROP , "tree phiprop")
DEFTIMEVAR (TV_TREE_DCE , "tree conservative DCE")
DEFTIMEVAR (TV_TREE_CD_DCE , "tree aggressive DCE")
DEFTIMEVAR (TV_TREE_DSE , "tree DSE")

300
gcc/tree-ssa-forwprop.c
View file

@ -1,5 +1,5 @@
/* Forward propagation of expressions for single use variables.
Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
This file is part of GCC.
@ -1082,301 +1082,3 @@ struct tree_opt_pass pass_forwprop = {
0 /* letter */
};
/* Structure to keep track of the value of a dereferenced PHI result
and the set of virtual operands used for that dereference. */
struct phiprop_d
{
tree value;
tree vop_stmt;
};
/* Verify if the value recorded for NAME in PHIVN is still valid at
the start of basic block BB. */
static bool
phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
{
tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
ssa_op_iter ui;
tree vuse;
/* The def stmts of all virtual uses need to be post-dominated
by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
{
tree use_stmt;
imm_use_iterator ui2;
bool ok = true;
FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
{
/* If BB does not dominate a VDEF, the value is invalid. */
if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
|| TREE_CODE (use_stmt) == PHI_NODE)
&& !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
{
ok = false;
BREAK_FROM_IMM_USE_STMT (ui2);
}
}
if (!ok)
return false;
}
return true;
}
/* Insert a new phi node for the dereference of PHI at basic_block
BB with the virtual operands from USE_STMT. */
static tree
phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
struct phiprop_d *phivn, size_t n)
{
tree res, new_phi;
edge_iterator ei;
edge e;
/* Build a new PHI node to replace the definition of
the indirect reference lhs. */
res = GIMPLE_STMT_OPERAND (use_stmt, 0);
SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
/* Add PHI arguments for each edge inserting loads of the
addressable operands. */
FOR_EACH_EDGE (e, ei, bb->preds)
{
tree old_arg, new_var, tmp;
old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
while (TREE_CODE (old_arg) == SSA_NAME
&& (SSA_NAME_VERSION (old_arg) >= n
|| phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if (TREE_CODE (old_arg) == SSA_NAME)
/* Reuse a formerly created dereference. */
new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
else
{
old_arg = TREE_OPERAND (old_arg, 0);
new_var = create_tmp_var (TREE_TYPE (old_arg), NULL);
tmp = build2 (GIMPLE_MODIFY_STMT, void_type_node,
NULL_TREE, unshare_expr (old_arg));
if (TREE_CODE (TREE_TYPE (old_arg)) == COMPLEX_TYPE
|| TREE_CODE (TREE_TYPE (old_arg)) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (new_var) = 1;
add_referenced_var (new_var);
new_var = make_ssa_name (new_var, tmp);
GIMPLE_STMT_OPERAND (tmp, 0) = new_var;
bsi_insert_on_edge (e, tmp);
update_stmt (tmp);
mark_symbols_for_renaming (tmp);
}
add_phi_arg (new_phi, new_var, e);
}
update_stmt (new_phi);
return res;
}
/* Propagate between the phi node arguments of PHI in BB and phi result
users. For now this matches
# p_2 = PHI <&x, &y>
<Lx>:;
p_3 = p_2;
z_2 = *p_3;
and converts it to
# z_2 = PHI <x, y>
<Lx>:;
Returns true if a transformation was done and edge insertions
need to be committed. Global data PHIVN and N is used to track
past transformation results. We need to be especially careful here
with aliasing issues as we are moving memory reads. */
static bool
propagate_with_phi (basic_block bb, tree phi, struct phiprop_d *phivn, size_t n)
{
tree ptr = PHI_RESULT (phi);
tree use_stmt, res = NULL_TREE;
block_stmt_iterator bsi;
imm_use_iterator ui;
use_operand_p arg_p, use;
ssa_op_iter i;
bool phi_inserted;
if (MTAG_P (SSA_NAME_VAR (ptr))
|| !POINTER_TYPE_P (TREE_TYPE (ptr))
|| !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
return false;
/* Check if we can "cheaply" dereference all phi arguments. */
FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
{
tree arg = USE_FROM_PTR (arg_p);
/* Walk the ssa chain until we reach a ssa name we already
created a value for or we reach a definition of the form
ssa_name_n = &var; */
while (TREE_CODE (arg) == SSA_NAME
&& !SSA_NAME_IS_DEFAULT_DEF (arg)
&& (SSA_NAME_VERSION (arg) >= n
|| phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (arg);
if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
return false;
arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if ((TREE_CODE (arg) != ADDR_EXPR
/* Avoid to have to decay *&a to a[0] later. */
|| !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
&& !(TREE_CODE (arg) == SSA_NAME
&& phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
&& phivn_valid_p (phivn, arg, bb)))
return false;
}
/* Find a dereferencing use. First follow (single use) ssa
copy chains for ptr. */
while (single_imm_use (ptr, &use, &use_stmt)
&& TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& GIMPLE_STMT_OPERAND (use_stmt, 1) == ptr
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME)
ptr = GIMPLE_STMT_OPERAND (use_stmt, 0);
/* Replace the first dereference of *ptr if there is one and if we
can move the loads to the place of the ptr phi node. */
phi_inserted = false;
FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
{
ssa_op_iter ui2;
tree vuse;
/* Check whether this is a load of *ptr. */
if (!(TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == INDIRECT_REF
&& TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) == ptr
/* We cannot replace a load that may throw or is volatile. */
&& !tree_can_throw_internal (use_stmt)))
continue;
/* Check if we can move the loads. The def stmts of all virtual uses
need to be post-dominated by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, use_stmt, ui2, SSA_OP_VUSE)
{
tree def_stmt = SSA_NAME_DEF_STMT (vuse);
if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
&& (bb_for_stmt (def_stmt) == bb
|| !dominated_by_p (CDI_DOMINATORS,
bb, bb_for_stmt (def_stmt))))
goto next;
}
/* Found a proper dereference. Insert a phi node if this
is the first load transformation. */
if (!phi_inserted)
{
res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
/* Remember the value we created for *ptr. */
phivn[SSA_NAME_VERSION (ptr)].value = res;
phivn[SSA_NAME_VERSION (ptr)].vop_stmt = use_stmt;
/* Remove old stmt. The phi is taken care of by DCE, if we
want to delete it here we also have to delete all intermediate
copies. */
bsi = bsi_for_stmt (use_stmt);
bsi_remove (&bsi, 0);
phi_inserted = true;
}
else
{
/* Further replacements are easy, just make a copy out of the
load. */
GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
update_stmt (use_stmt);
}
next:;
/* Continue searching for a proper dereference. */
}
return phi_inserted;
}
/* Helper walking the dominator tree starting from BB and processing
phi nodes with global data PHIVN and N. */
static bool
tree_ssa_phiprop_1 (basic_block bb, struct phiprop_d *phivn, size_t n)
{
bool did_something = false;
basic_block son;
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
did_something |= propagate_with_phi (bb, phi, phivn, n);
for (son = first_dom_son (CDI_DOMINATORS, bb);
son;
son = next_dom_son (CDI_DOMINATORS, son))
did_something |= tree_ssa_phiprop_1 (son, phivn, n);
return did_something;
}
/* Main entry for phiprop pass. */
static unsigned int
tree_ssa_phiprop (void)
{
struct phiprop_d *phivn;
calculate_dominance_info (CDI_DOMINATORS);
phivn = XCNEWVEC (struct phiprop_d, num_ssa_names);
if (tree_ssa_phiprop_1 (ENTRY_BLOCK_PTR, phivn, num_ssa_names))
bsi_commit_edge_inserts ();
free (phivn);
return 0;
}
static bool
gate_phiprop (void)
{
return 1;
}
struct tree_opt_pass pass_phiprop = {
"phiprop", /* name */
gate_phiprop, /* gate */
tree_ssa_phiprop, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_FORWPROP, /* tv_id */
PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func
| TODO_ggc_collect
| TODO_update_ssa
| TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};

388
gcc/tree-ssa-phiprop.c Normal file
View file

@ -0,0 +1,388 @@
/* Backward propagation of indirect loads through PHIs.
Copyright (C) 2007, 2008 Free Software Foundation, Inc.
Contributed by Richard Guenther <rguenther@suse.de>
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 "tm.h"
#include "ggc.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "basic-block.h"
#include "timevar.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-dump.h"
#include "langhooks.h"
#include "flags.h"
/* This pass propagates indirect loads through the PHI node for its
address to make the load source possiby non-addressable and to
allow for PHI optimization to trigger.
For example the pass changes
# addr_1 = PHI <&a, &b>
tmp_1 = *addr_1;
to
# tmp_1 = PHI <a, b>
but also handles more complex cenarios like
D.2077_2 = &this_1(D)->a1;
...
# b_12 = PHI <&c(2), D.2077_2(3)>
D.2114_13 = *b_12;
...
# b_15 = PHI <b_12(4), &b(5)>
D.2080_5 = &this_1(D)->a0;
...
# b_18 = PHI <D.2080_5(6), &c(7)>
...
# b_21 = PHI <b_15(8), b_18(9)>
D.2076_8 = *b_21;
where the addresses loaded are defined by PHIs itself.
The above happens for
std::max(std::min(a0, c), std::min(std::max(a1, c), b))
where this pass transforms it to a form later PHI optimization
recognizes and transforms it to the simple
D.2109_10 = this_1(D)->a1;
D.2110_11 = c;
D.2114_31 = MAX_EXPR <D.2109_10, D.2110_11>;
D.2115_14 = b;
D.2125_17 = MIN_EXPR <D.2115_14, D.2114_31>;
D.2119_16 = this_1(D)->a0;
D.2124_32 = MIN_EXPR <D.2110_11, D.2119_16>;
D.2076_33 = MAX_EXPR <D.2125_17, D.2124_32>;
The pass does a dominator walk processing loads using a basic-block
local analysis and stores the result for use by transformations on
dominated basic-blocks. */
/* Structure to keep track of the value of a dereferenced PHI result
and the set of virtual operands used for that dereference. */
struct phiprop_d
{
tree value;
tree vop_stmt;
};
/* Verify if the value recorded for NAME in PHIVN is still valid at
the start of basic block BB. */
static bool
phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
{
tree vop_stmt = phivn[SSA_NAME_VERSION (name)].vop_stmt;
ssa_op_iter ui;
tree vuse;
/* The def stmts of all virtual uses need to be post-dominated
by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, vop_stmt, ui, SSA_OP_VUSE)
{
tree use_stmt;
imm_use_iterator ui2;
bool ok = true;
FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
{
/* If BB does not dominate a VDEF, the value is invalid. */
if (((TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& !ZERO_SSA_OPERANDS (use_stmt, SSA_OP_VDEF))
|| TREE_CODE (use_stmt) == PHI_NODE)
&& !dominated_by_p (CDI_DOMINATORS, bb_for_stmt (use_stmt), bb))
{
ok = false;
BREAK_FROM_IMM_USE_STMT (ui2);
}
}
if (!ok)
return false;
}
return true;
}
/* Insert a new phi node for the dereference of PHI at basic_block
BB with the virtual operands from USE_STMT. */
static tree
phiprop_insert_phi (basic_block bb, tree phi, tree use_stmt,
struct phiprop_d *phivn, size_t n)
{
tree res, new_phi;
edge_iterator ei;
edge e;
/* Build a new PHI node to replace the definition of
the indirect reference lhs. */
res = GIMPLE_STMT_OPERAND (use_stmt, 0);
SSA_NAME_DEF_STMT (res) = new_phi = create_phi_node (res, bb);
/* Add PHI arguments for each edge inserting loads of the
addressable operands. */
FOR_EACH_EDGE (e, ei, bb->preds)
{
tree old_arg, new_var, tmp;
old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
while (TREE_CODE (old_arg) == SSA_NAME
&& (SSA_NAME_VERSION (old_arg) >= n
|| phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (old_arg);
old_arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if (TREE_CODE (old_arg) == SSA_NAME)
/* Reuse a formerly created dereference. */
new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
else
{
old_arg = TREE_OPERAND (old_arg, 0);
new_var = create_tmp_var (TREE_TYPE (old_arg), NULL);
tmp = build2 (GIMPLE_MODIFY_STMT, void_type_node,
NULL_TREE, unshare_expr (old_arg));
if (TREE_CODE (TREE_TYPE (old_arg)) == COMPLEX_TYPE
|| TREE_CODE (TREE_TYPE (old_arg)) == VECTOR_TYPE)
DECL_GIMPLE_REG_P (new_var) = 1;
add_referenced_var (new_var);
new_var = make_ssa_name (new_var, tmp);
GIMPLE_STMT_OPERAND (tmp, 0) = new_var;
bsi_insert_on_edge (e, tmp);
update_stmt (tmp);
mark_symbols_for_renaming (tmp);
}
add_phi_arg (new_phi, new_var, e);
}
update_stmt (new_phi);
return res;
}
/* Propagate between the phi node arguments of PHI in BB and phi result
users. For now this matches
# p_2 = PHI <&x, &y>
<Lx>:;
p_3 = p_2;
z_2 = *p_3;
and converts it to
# z_2 = PHI <x, y>
<Lx>:;
Returns true if a transformation was done and edge insertions
need to be committed. Global data PHIVN and N is used to track
past transformation results. We need to be especially careful here
with aliasing issues as we are moving memory reads. */
static bool
propagate_with_phi (basic_block bb, tree phi, struct phiprop_d *phivn, size_t n)
{
tree ptr = PHI_RESULT (phi);
tree use_stmt, res = NULL_TREE;
block_stmt_iterator bsi;
imm_use_iterator ui;
use_operand_p arg_p, use;
ssa_op_iter i;
bool phi_inserted;
if (MTAG_P (SSA_NAME_VAR (ptr))
|| !POINTER_TYPE_P (TREE_TYPE (ptr))
|| !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
return false;
/* Check if we can "cheaply" dereference all phi arguments. */
FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
{
tree arg = USE_FROM_PTR (arg_p);
/* Walk the ssa chain until we reach a ssa name we already
created a value for or we reach a definition of the form
ssa_name_n = &var; */
while (TREE_CODE (arg) == SSA_NAME
&& !SSA_NAME_IS_DEFAULT_DEF (arg)
&& (SSA_NAME_VERSION (arg) >= n
|| phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
{
tree def_stmt = SSA_NAME_DEF_STMT (arg);
if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
return false;
arg = GIMPLE_STMT_OPERAND (def_stmt, 1);
}
if ((TREE_CODE (arg) != ADDR_EXPR
/* Avoid to have to decay *&a to a[0] later. */
|| !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
&& !(TREE_CODE (arg) == SSA_NAME
&& phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
&& phivn_valid_p (phivn, arg, bb)))
return false;
}
/* Find a dereferencing use. First follow (single use) ssa
copy chains for ptr. */
while (single_imm_use (ptr, &use, &use_stmt)
&& TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& GIMPLE_STMT_OPERAND (use_stmt, 1) == ptr
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME)
ptr = GIMPLE_STMT_OPERAND (use_stmt, 0);
/* Replace the first dereference of *ptr if there is one and if we
can move the loads to the place of the ptr phi node. */
phi_inserted = false;
FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
{
ssa_op_iter ui2;
tree vuse;
/* Check whether this is a load of *ptr. */
if (!(TREE_CODE (use_stmt) == GIMPLE_MODIFY_STMT
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 0)) == SSA_NAME
&& TREE_CODE (GIMPLE_STMT_OPERAND (use_stmt, 1)) == INDIRECT_REF
&& TREE_OPERAND (GIMPLE_STMT_OPERAND (use_stmt, 1), 0) == ptr
/* We cannot replace a load that may throw or is volatile. */
&& !tree_can_throw_internal (use_stmt)))
continue;
/* Check if we can move the loads. The def stmts of all virtual uses
need to be post-dominated by bb. */
FOR_EACH_SSA_TREE_OPERAND (vuse, use_stmt, ui2, SSA_OP_VUSE)
{
tree def_stmt = SSA_NAME_DEF_STMT (vuse);
if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
&& (bb_for_stmt (def_stmt) == bb
|| !dominated_by_p (CDI_DOMINATORS,
bb, bb_for_stmt (def_stmt))))
goto next;
}
/* Found a proper dereference. Insert a phi node if this
is the first load transformation. */
if (!phi_inserted)
{
res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
/* Remember the value we created for *ptr. */
phivn[SSA_NAME_VERSION (ptr)].value = res;
phivn[SSA_NAME_VERSION (ptr)].vop_stmt = use_stmt;
/* Remove old stmt. The phi is taken care of by DCE, if we
want to delete it here we also have to delete all intermediate
copies. */
bsi = bsi_for_stmt (use_stmt);
bsi_remove (&bsi, 0);
phi_inserted = true;
}
else
{
/* Further replacements are easy, just make a copy out of the
load. */
GIMPLE_STMT_OPERAND (use_stmt, 1) = res;
update_stmt (use_stmt);
}
next:;
/* Continue searching for a proper dereference. */
}
return phi_inserted;
}
/* Helper walking the dominator tree starting from BB and processing
phi nodes with global data PHIVN and N. */
static bool
tree_ssa_phiprop_1 (basic_block bb, struct phiprop_d *phivn, size_t n)
{
bool did_something = false;
basic_block son;
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
did_something |= propagate_with_phi (bb, phi, phivn, n);
for (son = first_dom_son (CDI_DOMINATORS, bb);
son;
son = next_dom_son (CDI_DOMINATORS, son))
did_something |= tree_ssa_phiprop_1 (son, phivn, n);
return did_something;
}
/* Main entry for phiprop pass. */
static unsigned int
tree_ssa_phiprop (void)
{
struct phiprop_d *phivn;
calculate_dominance_info (CDI_DOMINATORS);
phivn = XCNEWVEC (struct phiprop_d, num_ssa_names);
if (tree_ssa_phiprop_1 (ENTRY_BLOCK_PTR, phivn, num_ssa_names))
bsi_commit_edge_inserts ();
free (phivn);
return 0;
}
static bool
gate_phiprop (void)
{
return 1;
}
struct tree_opt_pass pass_phiprop = {
"phiprop", /* name */
gate_phiprop, /* gate */
tree_ssa_phiprop, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_PHIPROP, /* tv_id */
PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func
| TODO_ggc_collect
| TODO_update_ssa
| TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};