/* Convert a program in SSA form into Normal form.
- Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
Contributed by Andrew Macleod <amacleod@redhat.com>
This file is part of GCC.
#include "tree-flow.h"
#include "timevar.h"
#include "tree-dump.h"
-#include "tree-ssa-live.h"
#include "tree-pass.h"
#include "toplev.h"
+#include "expr.h"
+#include "ssaexpand.h"
/* Used to hold all the components required to do SSA PHI elimination.
int size;
/* List of nodes in the elimination graph. */
- VEC(tree,heap) *nodes;
+ VEC(int,heap) *nodes;
/* The predecessor and successor edge list. */
VEC(int,heap) *edge_list;
edge e;
/* List of constant copies to emit. These are pushed on in pairs. */
+ VEC(int,heap) *const_dests;
VEC(tree,heap) *const_copies;
} *elim_graph;
-/* Create a temporary variable based on the type of variable T. Use T's name
- as the prefix. */
+/* For an edge E find out a good source location to associate with
+ instructions inserted on edge E. If E has an implicit goto set,
+ use its location. Otherwise search instructions in predecessors
+ of E for a location, and use that one. That makes sense because
+ we insert on edges for PHI nodes, and effects of PHIs happen on
+ the end of the predecessor conceptually. */
-static tree
-create_temp (tree t)
+static void
+set_location_for_edge (edge e)
{
- tree tmp;
- const char *name = NULL;
- tree type;
+ if (e->goto_locus)
+ {
+ set_curr_insn_source_location (e->goto_locus);
+ set_curr_insn_block (e->goto_block);
+ }
+ else
+ {
+ basic_block bb = e->src;
+ gimple_stmt_iterator gsi;
- if (TREE_CODE (t) == SSA_NAME)
- t = SSA_NAME_VAR (t);
+ do
+ {
+ for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ if (gimple_has_location (stmt) || gimple_block (stmt))
+ {
+ set_curr_insn_source_location (gimple_location (stmt));
+ set_curr_insn_block (gimple_block (stmt));
+ return;
+ }
+ }
+ /* Nothing found in this basic block. Make a half-assed attempt
+ to continue with another block. */
+ if (single_pred_p (bb))
+ bb = single_pred (bb);
+ else
+ bb = e->src;
+ }
+ while (bb != e->src);
+ }
+}
- gcc_assert (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == PARM_DECL);
+/* Emit insns to copy SRC into DEST converting SRC if necessary. */
- type = TREE_TYPE (t);
- tmp = DECL_NAME (t);
- if (tmp)
- name = IDENTIFIER_POINTER (tmp);
+static inline rtx
+emit_partition_copy (rtx dest, rtx src, int unsignedsrcp)
+{
+ rtx seq;
- if (name == NULL)
- name = "temp";
- tmp = create_tmp_var (type, name);
+ start_sequence ();
+
+ if (GET_MODE (src) != VOIDmode && GET_MODE (src) != GET_MODE (dest))
+ src = convert_to_mode (GET_MODE (dest), src, unsignedsrcp);
+ emit_move_insn (dest, src);
+
+ seq = get_insns ();
+ end_sequence ();
+
+ return seq;
+}
- if (DECL_DEBUG_EXPR_IS_FROM (t) && DECL_DEBUG_EXPR (t))
+/* Insert a copy instruction from partition SRC to DEST onto edge E. */
+
+static void
+insert_partition_copy_on_edge (edge e, int dest, int src)
+{
+ rtx seq;
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- SET_DECL_DEBUG_EXPR (tmp, DECL_DEBUG_EXPR (t));
- DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ fprintf (dump_file,
+ "Inserting a partition copy on edge BB%d->BB%d :"
+ "PART.%d = PART.%d",
+ e->src->index,
+ e->dest->index, dest, src);
+ fprintf (dump_file, "\n");
}
- else if (!DECL_IGNORED_P (t))
+
+ gcc_assert (SA.partition_to_pseudo[dest]);
+ gcc_assert (SA.partition_to_pseudo[src]);
+
+ set_location_for_edge (e);
+
+ seq = emit_partition_copy (SA.partition_to_pseudo[dest],
+ SA.partition_to_pseudo[src],
+ TYPE_UNSIGNED (TREE_TYPE (
+ partition_to_var (SA.map, src))));
+
+ insert_insn_on_edge (seq, e);
+}
+
+/* Insert a copy instruction from expression SRC to partition DEST
+ onto edge E. */
+
+static void
+insert_value_copy_on_edge (edge e, int dest, tree src)
+{
+ rtx seq, x;
+ enum machine_mode mode;
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- SET_DECL_DEBUG_EXPR (tmp, t);
- DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ fprintf (dump_file,
+ "Inserting a value copy on edge BB%d->BB%d : PART.%d = ",
+ e->src->index,
+ e->dest->index, dest);
+ print_generic_expr (dump_file, src, TDF_SLIM);
+ fprintf (dump_file, "\n");
}
- DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
- DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t);
- add_referenced_var (tmp);
-
- /* add_referenced_var will create the annotation and set up some
- of the flags in the annotation. However, some flags we need to
- inherit from our original variable. */
- set_symbol_mem_tag (tmp, symbol_mem_tag (t));
- if (is_call_clobbered (t))
- mark_call_clobbered (tmp, var_ann (t)->escape_mask);
-
- return tmp;
-}
+ gcc_assert (SA.partition_to_pseudo[dest]);
+
+ set_location_for_edge (e);
+
+ start_sequence ();
+ mode = GET_MODE (SA.partition_to_pseudo[dest]);
+ x = expand_expr (src, SA.partition_to_pseudo[dest], mode, EXPAND_NORMAL);
+ if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode)
+ x = convert_to_mode (mode, x, TYPE_UNSIGNED (TREE_TYPE (src)));
+ if (CONSTANT_P (x) && GET_MODE (x) == VOIDmode
+ && mode != TYPE_MODE (TREE_TYPE (src)))
+ x = convert_modes (mode, TYPE_MODE (TREE_TYPE (src)),
+ x, TYPE_UNSIGNED (TREE_TYPE (src)));
+ if (x != SA.partition_to_pseudo[dest])
+ emit_move_insn (SA.partition_to_pseudo[dest], x);
+ seq = get_insns ();
+ end_sequence ();
+
+ insert_insn_on_edge (seq, e);
+}
-/* This helper function fill insert a copy from a constant or variable SRC to
- variable DEST on edge E. */
+/* Insert a copy instruction from RTL expression SRC to partition DEST
+ onto edge E. */
static void
-insert_copy_on_edge (edge e, tree dest, tree src)
+insert_rtx_to_part_on_edge (edge e, int dest, rtx src, int unsignedsrcp)
{
- tree copy;
+ rtx seq;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file,
+ "Inserting a temp copy on edge BB%d->BB%d : PART.%d = ",
+ e->src->index,
+ e->dest->index, dest);
+ print_simple_rtl (dump_file, src);
+ fprintf (dump_file, "\n");
+ }
- copy = build_gimple_modify_stmt (dest, src);
- set_is_used (dest);
+ gcc_assert (SA.partition_to_pseudo[dest]);
+ set_location_for_edge (e);
- if (TREE_CODE (src) == ADDR_EXPR)
- src = TREE_OPERAND (src, 0);
- if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL)
- set_is_used (src);
+ seq = emit_partition_copy (SA.partition_to_pseudo[dest],
+ src,
+ unsignedsrcp);
+ insert_insn_on_edge (seq, e);
+}
+
+/* Insert a copy instruction from partition SRC to RTL lvalue DEST
+ onto edge E. */
+
+static void
+insert_part_to_rtx_on_edge (edge e, rtx dest, int src)
+{
+ rtx seq;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file,
- "Inserting a copy on edge BB%d->BB%d :",
+ "Inserting a temp copy on edge BB%d->BB%d : ",
e->src->index,
e->dest->index);
- print_generic_expr (dump_file, copy, dump_flags);
- fprintf (dump_file, "\n");
+ print_simple_rtl (dump_file, dest);
+ fprintf (dump_file, "= PART.%d\n", src);
}
- bsi_insert_on_edge (e, copy);
+ gcc_assert (SA.partition_to_pseudo[src]);
+ set_location_for_edge (e);
+
+ seq = emit_partition_copy (dest,
+ SA.partition_to_pseudo[src],
+ TYPE_UNSIGNED (TREE_TYPE (
+ partition_to_var (SA.map, src))));
+
+ insert_insn_on_edge (seq, e);
}
{
elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph));
- g->nodes = VEC_alloc (tree, heap, 30);
+ g->nodes = VEC_alloc (int, heap, 30);
+ g->const_dests = VEC_alloc (int, heap, 20);
g->const_copies = VEC_alloc (tree, heap, 20);
g->edge_list = VEC_alloc (int, heap, 20);
g->stack = VEC_alloc (int, heap, 30);
static inline void
clear_elim_graph (elim_graph g)
{
- VEC_truncate (tree, g->nodes, 0);
+ VEC_truncate (int, g->nodes, 0);
VEC_truncate (int, g->edge_list, 0);
}
VEC_free (int, heap, g->stack);
VEC_free (int, heap, g->edge_list);
VEC_free (tree, heap, g->const_copies);
- VEC_free (tree, heap, g->nodes);
+ VEC_free (int, heap, g->const_dests);
+ VEC_free (int, heap, g->nodes);
free (g);
}
static inline int
elim_graph_size (elim_graph g)
{
- return VEC_length (tree, g->nodes);
+ return VEC_length (int, g->nodes);
}
/* Add NODE to graph G, if it doesn't exist already. */
static inline void
-elim_graph_add_node (elim_graph g, tree node)
+elim_graph_add_node (elim_graph g, int node)
{
int x;
- tree t;
+ int t;
- for (x = 0; VEC_iterate (tree, g->nodes, x, t); x++)
+ for (x = 0; VEC_iterate (int, g->nodes, x, t); x++)
if (t == node)
return;
- VEC_safe_push (tree, heap, g->nodes, node);
+ VEC_safe_push (int, heap, g->nodes, node);
}
/* Add T to elimination graph G. */
static inline void
-eliminate_name (elim_graph g, tree T)
+eliminate_name (elim_graph g, int T)
{
elim_graph_add_node (g, T);
}
G->e. */
static void
-eliminate_build (elim_graph g, basic_block B)
+eliminate_build (elim_graph g)
{
- tree phi;
- tree T0, Ti;
+ tree Ti;
int p0, pi;
+ gimple_stmt_iterator gsi;
clear_elim_graph (g);
- for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start_phis (g->e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
{
- T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi));
-
+ gimple phi = gsi_stmt (gsi);
+
+ p0 = var_to_partition (g->map, gimple_phi_result (phi));
/* Ignore results which are not in partitions. */
- if (T0 == NULL_TREE)
+ if (p0 == NO_PARTITION)
continue;
Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
{
/* Save constant copies until all other copies have been emitted
on this edge. */
- VEC_safe_push (tree, heap, g->const_copies, T0);
+ VEC_safe_push (int, heap, g->const_dests, p0);
VEC_safe_push (tree, heap, g->const_copies, Ti);
}
else
{
- Ti = var_to_partition_to_var (g->map, Ti);
- if (T0 != Ti)
+ pi = var_to_partition (g->map, Ti);
+ if (p0 != pi)
{
- eliminate_name (g, T0);
- eliminate_name (g, Ti);
- p0 = var_to_partition (g->map, T0);
- pi = var_to_partition (g->map, Ti);
+ eliminate_name (g, p0);
+ eliminate_name (g, pi);
elim_graph_add_edge (g, p0, pi);
}
}
if (!TEST_BIT (g->visited, P))
{
elim_backward (g, P);
- insert_copy_on_edge (g->e,
- partition_to_var (g->map, P),
- partition_to_var (g->map, T));
+ insert_partition_copy_on_edge (g->e, P, T);
}
});
}
+/* Allocate a new pseudo register usable for storing values sitting
+ in NAME (a decl or SSA name), i.e. with matching mode and attributes. */
+
+static rtx
+get_temp_reg (tree name)
+{
+ tree var = TREE_CODE (name) == SSA_NAME ? SSA_NAME_VAR (name) : name;
+ tree type = TREE_TYPE (var);
+ int unsignedp = TYPE_UNSIGNED (type);
+ enum machine_mode reg_mode
+ = promote_mode (type, DECL_MODE (var), &unsignedp, 0);
+ rtx x = gen_reg_rtx (reg_mode);
+ if (POINTER_TYPE_P (type))
+ mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (var))));
+ return x;
+}
+
/* Insert required copies for T in graph G. Check for a strongly connected
region, and create a temporary to break the cycle if one is found. */
static void
elim_create (elim_graph g, int T)
{
- tree U;
int P, S;
if (elim_unvisited_predecessor (g, T))
{
- U = create_temp (partition_to_var (g->map, T));
- insert_copy_on_edge (g->e, U, partition_to_var (g->map, T));
+ tree var = partition_to_var (g->map, T);
+ rtx U = get_temp_reg (var);
+ int unsignedsrcp = TYPE_UNSIGNED (TREE_TYPE (var));
+
+ insert_part_to_rtx_on_edge (g->e, U, T);
FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
{
if (!TEST_BIT (g->visited, P))
{
elim_backward (g, P);
- insert_copy_on_edge (g->e, partition_to_var (g->map, P), U);
+ insert_rtx_to_part_on_edge (g->e, P, U, unsignedsrcp);
}
});
}
if (S != -1)
{
SET_BIT (g->visited, T);
- insert_copy_on_edge (g->e,
- partition_to_var (g->map, T),
- partition_to_var (g->map, S));
+ insert_partition_copy_on_edge (g->e, T, S);
}
}
-
}
eliminate_phi (edge e, elim_graph g)
{
int x;
- basic_block B = e->dest;
gcc_assert (VEC_length (tree, g->const_copies) == 0);
g->e = e;
- eliminate_build (g, B);
+ eliminate_build (g);
if (elim_graph_size (g) != 0)
{
- tree var;
+ int part;
sbitmap_zero (g->visited);
VEC_truncate (int, g->stack, 0);
- for (x = 0; VEC_iterate (tree, g->nodes, x, var); x++)
+ for (x = 0; VEC_iterate (int, g->nodes, x, part); x++)
{
- int p = var_to_partition (g->map, var);
- if (!TEST_BIT (g->visited, p))
- elim_forward (g, p);
+ if (!TEST_BIT (g->visited, part))
+ elim_forward (g, part);
}
sbitmap_zero (g->visited);
/* If there are any pending constant copies, issue them now. */
while (VEC_length (tree, g->const_copies) > 0)
{
- tree src, dest;
+ int dest;
+ tree src;
src = VEC_pop (tree, g->const_copies);
- dest = VEC_pop (tree, g->const_copies);
- insert_copy_on_edge (e, dest, src);
+ dest = VEC_pop (int, g->const_dests);
+ insert_value_copy_on_edge (e, dest, src);
}
}
-/* Take the ssa-name var_map MAP, and assign real variables to each
- partition. */
+/* Remove each argument from PHI. If an arg was the last use of an SSA_NAME,
+ check to see if this allows another PHI node to be removed. */
static void
-assign_vars (var_map map)
+remove_gimple_phi_args (gimple phi)
{
- int x, num;
- tree var, root;
- var_ann_t ann;
+ use_operand_p arg_p;
+ ssa_op_iter iter;
- num = num_var_partitions (map);
- for (x = 0; x < num; x++)
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- var = partition_to_var (map, x);
- if (TREE_CODE (var) != SSA_NAME)
- {
- ann = var_ann (var);
- /* It must already be coalesced. */
- gcc_assert (ann->out_of_ssa_tag == 1);
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "partition %d already has variable ", x);
- print_generic_expr (dump_file, var, TDF_SLIM);
- fprintf (dump_file, " assigned to it.\n");
- }
- }
- else
- {
- root = SSA_NAME_VAR (var);
- ann = var_ann (root);
- /* If ROOT is already associated, create a new one. */
- if (ann->out_of_ssa_tag)
- {
- root = create_temp (root);
- ann = var_ann (root);
- }
- /* ROOT has not been coalesced yet, so use it. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Partition %d is assigned to var ", x);
- print_generic_stmt (dump_file, root, TDF_SLIM);
- }
- change_partition_var (map, root, x);
- }
+ fprintf (dump_file, "Removing Dead PHI definition: ");
+ print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
}
-}
-
-
-/* Replace use operand P with whatever variable it has been rewritten to based
- on the partitions in MAP. EXPR is an optional expression vector over SSA
- versions which is used to replace P with an expression instead of a variable.
- If the stmt is changed, return true. */
-
-static inline bool
-replace_use_variable (var_map map, use_operand_p p, tree *expr)
-{
- tree new_var;
- tree var = USE_FROM_PTR (p);
- /* Check if we are replacing this variable with an expression. */
- if (expr)
+ FOR_EACH_PHI_ARG (arg_p, phi, iter, SSA_OP_USE)
{
- int version = SSA_NAME_VERSION (var);
- if (expr[version])
+ tree arg = USE_FROM_PTR (arg_p);
+ if (TREE_CODE (arg) == SSA_NAME)
{
- tree new_expr = GIMPLE_STMT_OPERAND (expr[version], 1);
- SET_USE (p, new_expr);
-
- /* Clear the stmt's RHS, or GC might bite us. */
- GIMPLE_STMT_OPERAND (expr[version], 1) = NULL_TREE;
- return true;
- }
- }
-
- new_var = var_to_partition_to_var (map, var);
- if (new_var)
- {
- SET_USE (p, new_var);
- set_is_used (new_var);
- return true;
- }
- return false;
-}
-
-
-/* Replace def operand DEF_P with whatever variable it has been rewritten to
- based on the partitions in MAP. EXPR is an optional expression vector over
- SSA versions which is used to replace DEF_P with an expression instead of a
- variable. If the stmt is changed, return true. */
+ /* Remove the reference to the existing argument. */
+ SET_USE (arg_p, NULL_TREE);
+ if (has_zero_uses (arg))
+ {
+ gimple stmt;
+ gimple_stmt_iterator gsi;
-static inline bool
-replace_def_variable (var_map map, def_operand_p def_p, tree *expr)
-{
- tree new_var;
- tree var = DEF_FROM_PTR (def_p);
+ stmt = SSA_NAME_DEF_STMT (arg);
- /* Do nothing if we are replacing this variable with an expression. */
- if (expr && expr[SSA_NAME_VERSION (var)])
- return true;
+ /* Also remove the def if it is a PHI node. */
+ if (gimple_code (stmt) == GIMPLE_PHI)
+ {
+ remove_gimple_phi_args (stmt);
+ gsi = gsi_for_stmt (stmt);
+ remove_phi_node (&gsi, true);
+ }
- new_var = var_to_partition_to_var (map, var);
- if (new_var)
- {
- SET_DEF (def_p, new_var);
- set_is_used (new_var);
- return true;
+ }
+ }
}
- return false;
}
-
-/* Remove any PHI node which is a virtual PHI. */
+/* Remove any PHI node which is a virtual PHI, or a PHI with no uses. */
static void
-eliminate_virtual_phis (void)
+eliminate_useless_phis (void)
{
basic_block bb;
- tree phi, next;
+ gimple_stmt_iterator gsi;
+ tree result;
FOR_EACH_BB (bb)
{
- for (phi = phi_nodes (bb); phi; phi = next)
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
{
- next = PHI_CHAIN (phi);
- if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
+ gimple phi = gsi_stmt (gsi);
+ result = gimple_phi_result (phi);
+ if (!is_gimple_reg (SSA_NAME_VAR (result)))
{
#ifdef ENABLE_CHECKING
- int i;
- /* There should be no arguments of this PHI which are in
- the partition list, or we get incorrect results. */
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
+ size_t i;
+ /* There should be no arguments which are not virtual, or the
+ results will be incorrect. */
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = PHI_ARG_DEF (phi, i);
if (TREE_CODE (arg) == SSA_NAME
fprintf (stderr, "Argument of PHI is not virtual (");
print_generic_expr (stderr, arg, TDF_SLIM);
fprintf (stderr, "), but the result is :");
- print_generic_stmt (stderr, phi, TDF_SLIM);
+ print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
internal_error ("SSA corruption");
}
}
#endif
- remove_phi_node (phi, NULL_TREE, true);
+ remove_phi_node (&gsi, true);
+ }
+ else
+ {
+ /* Also remove real PHIs with no uses. */
+ if (has_zero_uses (result))
+ {
+ remove_gimple_phi_args (phi);
+ remove_phi_node (&gsi, true);
+ }
+ else
+ gsi_next (&gsi);
}
}
}
variable. */
static void
-rewrite_trees (var_map map, tree *values)
+rewrite_trees (var_map map ATTRIBUTE_UNUSED)
{
- elim_graph g;
- basic_block bb;
- block_stmt_iterator si;
- edge e;
- tree phi;
- bool changed;
-
#ifdef ENABLE_CHECKING
+ basic_block bb;
/* Search for PHIs where the destination has no partition, but one
or more arguments has a partition. This should not happen and can
create incorrect code. */
FOR_EACH_BB (bb)
{
- tree phi;
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ gimple_stmt_iterator gsi;
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi));
+ gimple phi = gsi_stmt (gsi);
+ tree T0 = var_to_partition_to_var (map, gimple_phi_result (phi));
if (T0 == NULL_TREE)
{
- int i;
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
+ size_t i;
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = PHI_ARG_DEF (phi, i);
fprintf (stderr, "Argument of PHI is in a partition :(");
print_generic_expr (stderr, arg, TDF_SLIM);
fprintf (stderr, "), but the result is not :");
- print_generic_stmt (stderr, phi, TDF_SLIM);
+ print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
internal_error ("SSA corruption");
}
}
}
}
#endif
-
- /* Replace PHI nodes with any required copies. */
- g = new_elim_graph (map->num_partitions);
- g->map = map;
- FOR_EACH_BB (bb)
- {
- for (si = bsi_start (bb); !bsi_end_p (si); )
- {
- tree stmt = bsi_stmt (si);
- use_operand_p use_p, copy_use_p;
- def_operand_p def_p;
- bool remove = false, is_copy = false;
- int num_uses = 0;
- stmt_ann_t ann;
- ssa_op_iter iter;
-
- ann = stmt_ann (stmt);
- changed = false;
-
- if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
- && (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == SSA_NAME))
- is_copy = true;
-
- copy_use_p = NULL_USE_OPERAND_P;
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
- {
- if (replace_use_variable (map, use_p, values))
- changed = true;
- copy_use_p = use_p;
- num_uses++;
- }
-
- if (num_uses != 1)
- is_copy = false;
-
- def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF);
-
- if (def_p != NULL)
- {
- /* Mark this stmt for removal if it is the list of replaceable
- expressions. */
- if (values && values[SSA_NAME_VERSION (DEF_FROM_PTR (def_p))])
- remove = true;
- else
- {
- if (replace_def_variable (map, def_p, NULL))
- changed = true;
- /* If both SSA_NAMEs coalesce to the same variable,
- mark the now redundant copy for removal. */
- if (is_copy)
- {
- gcc_assert (copy_use_p != NULL_USE_OPERAND_P);
- if (DEF_FROM_PTR (def_p) == USE_FROM_PTR (copy_use_p))
- remove = true;
- }
- }
- }
- else
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
- if (replace_def_variable (map, def_p, NULL))
- changed = true;
-
- /* Remove any stmts marked for removal. */
- if (remove)
- bsi_remove (&si, true);
- else
- {
- if (changed)
- if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
- tree_purge_dead_eh_edges (bb);
- bsi_next (&si);
- }
- }
-
- phi = phi_nodes (bb);
- if (phi)
- {
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->preds)
- eliminate_phi (e, g);
- }
- }
-
- delete_elim_graph (g);
-}
-
-/* These are the local work structures used to determine the best place to
- insert the copies that were placed on edges by the SSA->normal pass.. */
-static VEC(edge,heap) *edge_leader;
-static VEC(tree,heap) *stmt_list;
-static bitmap leader_has_match = NULL;
-static edge leader_match = NULL;
-
-
-/* Pass this function to make_forwarder_block so that all the edges with
- matching PENDING_STMT lists to 'curr_stmt_list' get redirected. E is the
- edge to test for a match. */
-
-static inline bool
-same_stmt_list_p (edge e)
-{
- return (e->aux == (PTR) leader_match) ? true : false;
}
+/* Given the out-of-ssa info object SA (with prepared partitions)
+ eliminate all phi nodes in all basic blocks. Afterwards no
+ basic block will have phi nodes anymore and there are possibly
+ some RTL instructions inserted on edges. */
-/* Return TRUE if S1 and S2 are equivalent copies. */
-
-static inline bool
-identical_copies_p (const_tree s1, const_tree s2)
-{
-#ifdef ENABLE_CHECKING
- gcc_assert (TREE_CODE (s1) == GIMPLE_MODIFY_STMT);
- gcc_assert (TREE_CODE (s2) == GIMPLE_MODIFY_STMT);
- gcc_assert (DECL_P (GIMPLE_STMT_OPERAND (s1, 0)));
- gcc_assert (DECL_P (GIMPLE_STMT_OPERAND (s2, 0)));
-#endif
-
- if (GIMPLE_STMT_OPERAND (s1, 0) != GIMPLE_STMT_OPERAND (s2, 0))
- return false;
-
- s1 = GIMPLE_STMT_OPERAND (s1, 1);
- s2 = GIMPLE_STMT_OPERAND (s2, 1);
-
- if (s1 != s2)
- return false;
-
- return true;
-}
-
-
-/* Compare the PENDING_STMT list for edges E1 and E2. Return true if the lists
- contain the same sequence of copies. */
-
-static inline bool
-identical_stmt_lists_p (const_edge e1, const_edge e2)
-{
- tree t1 = PENDING_STMT (e1);
- tree t2 = PENDING_STMT (e2);
- tree_stmt_iterator tsi1, tsi2;
-
- gcc_assert (TREE_CODE (t1) == STATEMENT_LIST);
- gcc_assert (TREE_CODE (t2) == STATEMENT_LIST);
-
- for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
- !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
- tsi_next (&tsi1), tsi_next (&tsi2))
- {
- if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
- break;
- }
-
- if (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
- return false;
-
- return true;
-}
-
-
-/* Allocate data structures used in analyze_edges_for_bb. */
-
-static void
-init_analyze_edges_for_bb (void)
-{
- edge_leader = VEC_alloc (edge, heap, 25);
- stmt_list = VEC_alloc (tree, heap, 25);
- leader_has_match = BITMAP_ALLOC (NULL);
-}
-
-
-/* Free data structures used in analyze_edges_for_bb. */
-
-static void
-fini_analyze_edges_for_bb (void)
-{
- VEC_free (edge, heap, edge_leader);
- VEC_free (tree, heap, stmt_list);
- BITMAP_FREE (leader_has_match);
-}
-
-
-/* Look at all the incoming edges to block BB, and decide where the best place
- to insert the stmts on each edge are, and perform those insertions. */
-
-static void
-analyze_edges_for_bb (basic_block bb)
-{
- edge e;
- edge_iterator ei;
- int count;
- unsigned int x;
- bool have_opportunity;
- block_stmt_iterator bsi;
- tree stmt;
- edge single_edge = NULL;
- bool is_label;
- edge leader;
-
- count = 0;
-
- /* Blocks which contain at least one abnormal edge cannot use
- make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs
- found on edges in these block. */
- have_opportunity = true;
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_ABNORMAL)
- {
- have_opportunity = false;
- break;
- }
-
- if (!have_opportunity)
- {
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (PENDING_STMT (e))
- bsi_commit_one_edge_insert (e, NULL);
- return;
- }
-
- /* Find out how many edges there are with interesting pending stmts on them.
- Commit the stmts on edges we are not interested in. */
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- if (PENDING_STMT (e))
- {
- gcc_assert (!(e->flags & EDGE_ABNORMAL));
- if (e->flags & EDGE_FALLTHRU)
- {
- bsi = bsi_start (e->src);
- if (!bsi_end_p (bsi))
- {
- stmt = bsi_stmt (bsi);
- bsi_next (&bsi);
- gcc_assert (stmt != NULL_TREE);
- is_label = (TREE_CODE (stmt) == LABEL_EXPR);
- /* Punt if it has non-label stmts, or isn't local. */
- if (!is_label || DECL_NONLOCAL (TREE_OPERAND (stmt, 0))
- || !bsi_end_p (bsi))
- {
- bsi_commit_one_edge_insert (e, NULL);
- continue;
- }
- }
- }
- single_edge = e;
- count++;
- }
- }
-
- /* If there aren't at least 2 edges, no sharing will happen. */
- if (count < 2)
- {
- if (single_edge)
- bsi_commit_one_edge_insert (single_edge, NULL);
- return;
- }
-
- /* Ensure that we have empty worklists. */
-#ifdef ENABLE_CHECKING
- gcc_assert (VEC_length (edge, edge_leader) == 0);
- gcc_assert (VEC_length (tree, stmt_list) == 0);
- gcc_assert (bitmap_empty_p (leader_has_match));
-#endif
-
- /* Find the "leader" block for each set of unique stmt lists. Preference is
- given to FALLTHRU blocks since they would need a GOTO to arrive at another
- block. The leader edge destination is the block which all the other edges
- with the same stmt list will be redirected to. */
- have_opportunity = false;
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- if (PENDING_STMT (e))
- {
- bool found = false;
-
- /* Look for the same stmt list in edge leaders list. */
- for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
- {
- if (identical_stmt_lists_p (leader, e))
- {
- /* Give this edge the same stmt list pointer. */
- PENDING_STMT (e) = NULL;
- e->aux = leader;
- bitmap_set_bit (leader_has_match, x);
- have_opportunity = found = true;
- break;
- }
- }
-
- /* If no similar stmt list, add this edge to the leader list. */
- if (!found)
- {
- VEC_safe_push (edge, heap, edge_leader, e);
- VEC_safe_push (tree, heap, stmt_list, PENDING_STMT (e));
- }
- }
- }
-
- /* If there are no similar lists, just issue the stmts. */
- if (!have_opportunity)
- {
- for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
- bsi_commit_one_edge_insert (leader, NULL);
- VEC_truncate (edge, edge_leader, 0);
- VEC_truncate (tree, stmt_list, 0);
- bitmap_clear (leader_has_match);
- return;
- }
-
- if (dump_file)
- fprintf (dump_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
- bb->index);
-
- /* For each common list, create a forwarding block and issue the stmt's
- in that block. */
- for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
- if (bitmap_bit_p (leader_has_match, x))
- {
- edge new_edge;
- block_stmt_iterator bsi;
- tree curr_stmt_list;
-
- leader_match = leader;
-
- /* The tree_* cfg manipulation routines use the PENDING_EDGE field
- for various PHI manipulations, so it gets cleared when calls are
- made to make_forwarder_block(). So make sure the edge is clear,
- and use the saved stmt list. */
- PENDING_STMT (leader) = NULL;
- leader->aux = leader;
- curr_stmt_list = VEC_index (tree, stmt_list, x);
-
- new_edge = make_forwarder_block (leader->dest, same_stmt_list_p,
- NULL);
- bb = new_edge->dest;
- if (dump_file)
- {
- fprintf (dump_file, "Splitting BB %d for Common stmt list. ",
- leader->dest->index);
- fprintf (dump_file, "Original block is now BB%d.\n", bb->index);
- print_generic_stmt (dump_file, curr_stmt_list, TDF_VOPS);
- }
-
- FOR_EACH_EDGE (e, ei, new_edge->src->preds)
- {
- e->aux = NULL;
- if (dump_file)
- fprintf (dump_file, " Edge (%d->%d) lands here.\n",
- e->src->index, e->dest->index);
- }
-
- bsi = bsi_last (leader->dest);
- bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
-
- leader_match = NULL;
- /* We should never get a new block now. */
- }
- else
- {
- PENDING_STMT (leader) = VEC_index (tree, stmt_list, x);
- bsi_commit_one_edge_insert (leader, NULL);
- }
-
-
- /* Clear the working data structures. */
- VEC_truncate (edge, edge_leader, 0);
- VEC_truncate (tree, stmt_list, 0);
- bitmap_clear (leader_has_match);
-}
-
-
-/* This function will analyze the insertions which were performed on edges,
- and decide whether they should be left on that edge, or whether it is more
- efficient to emit some subset of them in a single block. All stmts are
- inserted somewhere. */
-
-static void
-perform_edge_inserts (void)
+void
+expand_phi_nodes (struct ssaexpand *sa)
{
basic_block bb;
+ elim_graph g = new_elim_graph (sa->map->num_partitions);
+ g->map = sa->map;
- if (dump_file)
- fprintf(dump_file, "Analyzing Edge Insertions.\n");
-
- /* analyze_edges_for_bb calls make_forwarder_block, which tries to
- incrementally update the dominator information. Since we don't
- need dominator information after this pass, go ahead and free the
- dominator information. */
- free_dominance_info (CDI_DOMINATORS);
- free_dominance_info (CDI_POST_DOMINATORS);
-
- /* Allocate data structures used in analyze_edges_for_bb. */
- init_analyze_edges_for_bb ();
-
- FOR_EACH_BB (bb)
- analyze_edges_for_bb (bb);
-
- analyze_edges_for_bb (EXIT_BLOCK_PTR);
-
- /* Free data structures used in analyze_edges_for_bb. */
- fini_analyze_edges_for_bb ();
-
-#ifdef ENABLE_CHECKING
- {
- edge_iterator ei;
- edge e;
- FOR_EACH_BB (bb)
+ FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR, next_bb)
+ if (!gimple_seq_empty_p (phi_nodes (bb)))
{
+ edge e;
+ edge_iterator ei;
FOR_EACH_EDGE (e, ei, bb->preds)
+ eliminate_phi (e, g);
+ set_phi_nodes (bb, NULL);
+ /* We can't redirect EH edges in RTL land, so we need to do this
+ here. Redirection happens only when splitting is necessary,
+ which it is only for critical edges, normally. For EH edges
+ it might also be necessary when the successor has more than
+ one predecessor. In that case the edge is either required to
+ be fallthru (which EH edges aren't), or the predecessor needs
+ to end with a jump (which again, isn't the case with EH edges).
+ Hence, split all EH edges on which we inserted instructions
+ and whose successor has multiple predecessors. */
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
{
- if (PENDING_STMT (e))
- error (" Pending stmts not issued on PRED edge (%d, %d)\n",
- e->src->index, e->dest->index);
- }
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- if (PENDING_STMT (e))
- error (" Pending stmts not issued on SUCC edge (%d, %d)\n",
- e->src->index, e->dest->index);
+ if (e->insns.r && (e->flags & EDGE_EH)
+ && !single_pred_p (e->dest))
+ {
+ rtx insns = e->insns.r;
+ basic_block bb;
+ e->insns.r = NULL_RTX;
+ bb = split_edge (e);
+ single_pred_edge (bb)->insns.r = insns;
+ }
+ else
+ ei_next (&ei);
}
}
- FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
- {
- if (PENDING_STMT (e))
- error (" Pending stmts not issued on ENTRY edge (%d, %d)\n",
- e->src->index, e->dest->index);
- }
- FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
- {
- if (PENDING_STMT (e))
- error (" Pending stmts not issued on EXIT edge (%d, %d)\n",
- e->src->index, e->dest->index);
- }
- }
-#endif
+
+ delete_elim_graph (g);
}
should also be used. */
static void
-remove_ssa_form (bool perform_ter)
+remove_ssa_form (bool perform_ter, struct ssaexpand *sa)
{
- basic_block bb;
- tree phi, next;
- tree *values = NULL;
+ bitmap values = NULL;
var_map map;
+ unsigned i;
map = coalesce_ssa_name ();
dump_replaceable_exprs (dump_file, values);
}
- /* Assign real variables to the partitions now. */
- assign_vars (map);
+ rewrite_trees (map);
- if (dump_file && (dump_flags & TDF_DETAILS))
+ sa->map = map;
+ sa->values = values;
+ sa->partition_has_default_def = BITMAP_ALLOC (NULL);
+ for (i = 1; i < num_ssa_names; i++)
{
- fprintf (dump_file, "After Base variable replacement:\n");
- dump_var_map (dump_file, map);
+ tree t = ssa_name (i);
+ if (t && SSA_NAME_IS_DEFAULT_DEF (t))
+ {
+ int p = var_to_partition (map, t);
+ if (p != NO_PARTITION)
+ bitmap_set_bit (sa->partition_has_default_def, p);
+ }
}
+}
- rewrite_trees (map, values);
- if (values)
- free (values);
+/* If not already done so for basic block BB, assign increasing uids
+ to each of its instructions. */
- /* Remove PHI nodes which have been translated back to real variables. */
- FOR_EACH_BB (bb)
+static void
+maybe_renumber_stmts_bb (basic_block bb)
+{
+ unsigned i = 0;
+ gimple_stmt_iterator gsi;
+
+ if (!bb->aux)
+ return;
+ bb->aux = NULL;
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- for (phi = phi_nodes (bb); phi; phi = next)
- {
- next = PHI_CHAIN (phi);
- remove_phi_node (phi, NULL_TREE, true);
- }
+ gimple stmt = gsi_stmt (gsi);
+ gimple_set_uid (stmt, i);
+ i++;
}
+}
+
+
+/* Return true if we can determine that the SSA_NAMEs RESULT (a result
+ of a PHI node) and ARG (one of its arguments) conflict. Return false
+ otherwise, also when we simply aren't sure. */
- /* If any copies were inserted on edges, analyze and insert them now. */
- perform_edge_inserts ();
+static bool
+trivially_conflicts_p (basic_block bb, tree result, tree arg)
+{
+ use_operand_p use;
+ imm_use_iterator imm_iter;
+ gimple defa = SSA_NAME_DEF_STMT (arg);
+
+ /* If ARG isn't defined in the same block it's too complicated for
+ our little mind. */
+ if (gimple_bb (defa) != bb)
+ return false;
- delete_var_map (map);
+ FOR_EACH_IMM_USE_FAST (use, imm_iter, result)
+ {
+ gimple use_stmt = USE_STMT (use);
+ /* Now, if there's a use of RESULT that lies outside this basic block,
+ then there surely is a conflict with ARG. */
+ if (gimple_bb (use_stmt) != bb)
+ return true;
+ if (gimple_code (use_stmt) == GIMPLE_PHI)
+ continue;
+ /* The use now is in a real stmt of BB, so if ARG was defined
+ in a PHI node (like RESULT) both conflict. */
+ if (gimple_code (defa) == GIMPLE_PHI)
+ return true;
+ maybe_renumber_stmts_bb (bb);
+ /* If the use of RESULT occurs after the definition of ARG,
+ the two conflict too. */
+ if (gimple_uid (defa) < gimple_uid (use_stmt))
+ return true;
+ }
+
+ return false;
}
insert_backedge_copies (void)
{
basic_block bb;
+ gimple_stmt_iterator gsi;
FOR_EACH_BB (bb)
{
- tree phi;
+ /* Mark block as possibly needing calculation of UIDs. */
+ bb->aux = &bb->aux;
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree result = PHI_RESULT (phi);
+ gimple phi = gsi_stmt (gsi);
+ tree result = gimple_phi_result (phi);
tree result_var;
- int i;
+ size_t i;
if (!is_gimple_reg (result))
continue;
result_var = SSA_NAME_VAR (result);
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
{
- tree arg = PHI_ARG_DEF (phi, i);
- edge e = PHI_ARG_EDGE (phi, i);
+ tree arg = gimple_phi_arg_def (phi, i);
+ edge e = gimple_phi_arg_edge (phi, i);
/* If the argument is not an SSA_NAME, then we will need a
constant initialization. If the argument is an SSA_NAME with
needed. */
if ((e->flags & EDGE_DFS_BACK)
&& (TREE_CODE (arg) != SSA_NAME
- || SSA_NAME_VAR (arg) != result_var))
+ || SSA_NAME_VAR (arg) != result_var
+ || trivially_conflicts_p (bb, result, arg)))
{
- tree stmt, name, last = NULL;
- block_stmt_iterator bsi;
+ tree name;
+ gimple stmt, last = NULL;
+ gimple_stmt_iterator gsi2;
- bsi = bsi_last (PHI_ARG_EDGE (phi, i)->src);
- if (!bsi_end_p (bsi))
- last = bsi_stmt (bsi);
+ gsi2 = gsi_last_bb (gimple_phi_arg_edge (phi, i)->src);
+ if (!gsi_end_p (gsi2))
+ last = gsi_stmt (gsi2);
/* In theory the only way we ought to get back to the
start of a loop should be with a COND_EXPR or GOTO_EXPR.
/* Create a new instance of the underlying variable of the
PHI result. */
- stmt = build_gimple_modify_stmt (NULL_TREE,
- PHI_ARG_DEF (phi, i));
+ stmt = gimple_build_assign (result_var,
+ gimple_phi_arg_def (phi, i));
name = make_ssa_name (result_var, stmt);
- GIMPLE_STMT_OPERAND (stmt, 0) = name;
+ gimple_assign_set_lhs (stmt, name);
/* Insert the new statement into the block and update
the PHI node. */
if (last && stmt_ends_bb_p (last))
- bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
+ gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
else
- bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
+ gsi_insert_after (&gsi2, stmt, GSI_NEW_STMT);
SET_PHI_ARG_DEF (phi, i, name);
}
}
}
+
+ /* Unmark this block again. */
+ bb->aux = NULL;
}
}
+/* Free all memory associated with going out of SSA form. SA is
+ the outof-SSA info object. */
+
+void
+finish_out_of_ssa (struct ssaexpand *sa)
+{
+ free (sa->partition_to_pseudo);
+ if (sa->values)
+ BITMAP_FREE (sa->values);
+ delete_var_map (sa->map);
+ BITMAP_FREE (sa->partition_has_default_def);
+ memset (sa, 0, sizeof *sa);
+}
+
/* Take the current function out of SSA form, translating PHIs as described in
R. Morgan, ``Building an Optimizing Compiler'',
Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
-static unsigned int
-rewrite_out_of_ssa (void)
+unsigned int
+rewrite_out_of_ssa (struct ssaexpand *sa)
{
/* If elimination of a PHI requires inserting a copy on a backedge,
then we will have to split the backedge which has numerous
copies into the loop itself. */
insert_backedge_copies ();
- eliminate_virtual_phis ();
+
+ /* Eliminate PHIs which are of no use, such as virtual or dead phis. */
+ eliminate_useless_phis ();
if (dump_file && (dump_flags & TDF_DETAILS))
- dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
+ gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
- remove_ssa_form (flag_tree_ter && !flag_mudflap);
+ remove_ssa_form (flag_tree_ter, sa);
if (dump_file && (dump_flags & TDF_DETAILS))
- dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
+ gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
- cfun->gimple_df->in_ssa_p = false;
return 0;
}
-
-
-/* Define the parameters of the out of SSA pass. */
-
-struct tree_opt_pass pass_del_ssa =
-{
- "optimized", /* name */
- NULL, /* gate */
- rewrite_out_of_ssa, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_SSA_TO_NORMAL, /* tv_id */
- PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
- 0, /* properties_provided */
- /* ??? If TER is enabled, we also kill gimple. */
- PROP_ssa, /* properties_destroyed */
- TODO_verify_ssa | TODO_verify_flow
- | TODO_verify_stmts, /* todo_flags_start */
- TODO_dump_func
- | TODO_ggc_collect
- | TODO_remove_unused_locals, /* todo_flags_finish */
- 0 /* letter */
-};
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