[PATCH] Split phiprop from tree-ssa-forwprop.c into its own file
Richard Guenther
rguenther@suse.de
Wed Mar 12 12:14:00 GMT 2008
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
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.
Index: Makefile.in
===================================================================
*** Makefile.in (revision 133138)
--- Makefile.in (working copy)
*************** OBJS-common = \
*** 1194,1199 ****
--- 1194,1200 ----
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 \
*************** tree-ssa-forwprop.o : tree-ssa-forwprop.
*** 2017,2022 ****
--- 2018,2027 ----
$(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)
Index: timevar.def
===================================================================
*** timevar.def (revision 133138)
--- timevar.def (working copy)
*************** DEFTIMEVAR (TV_TREE_FRE , "tree FR
*** 109,114 ****
--- 109,115 ----
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")
Index: tree-ssa-phiprop.c
===================================================================
*** tree-ssa-phiprop.c (revision 0)
--- tree-ssa-phiprop.c (revision 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 */
+ };
Index: tree-ssa-forwprop.c
===================================================================
*** tree-ssa-forwprop.c (revision 133138)
--- tree-ssa-forwprop.c (working copy)
***************
*** 1,5 ****
/* Forward propagation of expressions for single use variables.
! Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
This file is part of GCC.
--- 1,5 ----
/* Forward propagation of expressions for single use variables.
! Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
This file is part of GCC.
*************** struct tree_opt_pass pass_forwprop = {
*** 1082,1382 ****
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 */
- };
--- 1082,1084 ----
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