tree-ssa-loop-im.c [plain text]
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "output.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "tree-dump.h"
#include "timevar.h"
#include "cfgloop.h"
#include "domwalk.h"
#include "params.h"
#include "tree-pass.h"
#include "flags.h"
struct depend
{
tree stmt;
struct depend *next;
};
struct lim_aux_data
{
struct loop *max_loop;
struct loop *tgt_loop;
struct loop *always_executed_in;
bool sm_done;
unsigned cost;
struct depend *depends;
};
#define LIM_DATA(STMT) ((struct lim_aux_data *) (stmt_ann (STMT)->common.aux))
struct use
{
tree *addr;
tree stmt;
struct use *next;
};
#define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE))
#define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
static unsigned max_uid;
static bool
unsafe_memory_access_p (tree mem)
{
tree base, idx;
switch (TREE_CODE (mem))
{
case ADDR_EXPR:
return false;
case COMPONENT_REF:
case REALPART_EXPR:
case IMAGPART_EXPR:
return unsafe_memory_access_p (TREE_OPERAND (mem, 0));
case ARRAY_REF:
base = TREE_OPERAND (mem, 0);
idx = TREE_OPERAND (mem, 1);
if (unsafe_memory_access_p (base))
return true;
if (TREE_CODE_CLASS (TREE_CODE (idx)) != 'c')
return true;
return !in_array_bounds_p (base, idx);
case INDIRECT_REF:
return true;
default:
return false;
}
}
enum move_pos
movement_possibility (tree stmt)
{
tree lhs, rhs;
if (flag_unswitch_loops
&& TREE_CODE (stmt) == COND_EXPR)
{
get_stmt_operands (stmt);
return MOVE_POSSIBLE;
}
if (TREE_CODE (stmt) != MODIFY_EXPR)
return MOVE_IMPOSSIBLE;
if (stmt_ends_bb_p (stmt))
return MOVE_IMPOSSIBLE;
get_stmt_operands (stmt);
if (stmt_ann (stmt)->has_volatile_ops)
return MOVE_IMPOSSIBLE;
lhs = TREE_OPERAND (stmt, 0);
if (TREE_CODE (lhs) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
return MOVE_IMPOSSIBLE;
rhs = TREE_OPERAND (stmt, 1);
if (TREE_SIDE_EFFECTS (rhs))
return MOVE_IMPOSSIBLE;
if (TREE_CODE (lhs) != SSA_NAME
|| tree_could_trap_p (rhs)
|| unsafe_memory_access_p (rhs))
return MOVE_PRESERVE_EXECUTION;
return MOVE_POSSIBLE;
}
static struct loop *
outermost_invariant_loop (tree def, struct loop *loop)
{
tree def_stmt;
basic_block def_bb;
struct loop *max_loop;
if (is_gimple_min_invariant (def))
return superloop_at_depth (loop, 1);
def_stmt = SSA_NAME_DEF_STMT (def);
def_bb = bb_for_stmt (def_stmt);
if (!def_bb)
return superloop_at_depth (loop, 1);
max_loop = find_common_loop (loop, def_bb->loop_father);
if (LIM_DATA (def_stmt) && LIM_DATA (def_stmt)->max_loop)
max_loop = find_common_loop (max_loop,
LIM_DATA (def_stmt)->max_loop->outer);
if (max_loop == loop)
return NULL;
max_loop = superloop_at_depth (loop, max_loop->depth + 1);
return max_loop;
}
static bool
add_dependency (tree def, struct lim_aux_data *data, struct loop *loop,
bool add_cost)
{
tree def_stmt = SSA_NAME_DEF_STMT (def);
basic_block def_bb = bb_for_stmt (def_stmt);
struct loop *max_loop;
struct depend *dep;
if (!def_bb)
return true;
max_loop = outermost_invariant_loop (def, loop);
if (!max_loop)
return false;
if (flow_loop_nested_p (data->max_loop, max_loop))
data->max_loop = max_loop;
if (!LIM_DATA (def_stmt))
return true;
if (add_cost
&& def_bb->loop_father == loop)
data->cost += LIM_DATA (def_stmt)->cost;
dep = xmalloc (sizeof (struct depend));
dep->stmt = def_stmt;
dep->next = data->depends;
data->depends = dep;
return true;
}
static unsigned
stmt_cost (tree stmt)
{
tree lhs, rhs;
unsigned cost = 1;
if (TREE_CODE (stmt) == COND_EXPR)
return 20;
lhs = TREE_OPERAND (stmt, 0);
rhs = TREE_OPERAND (stmt, 1);
if (!is_gimple_variable (lhs))
cost += 20;
if (is_gimple_addr_expr_arg (rhs) && !is_gimple_variable (rhs))
cost += 20;
switch (TREE_CODE (rhs))
{
case CALL_EXPR:
rhs = get_callee_fndecl (rhs);
if (DECL_BUILT_IN (rhs)
&& DECL_FUNCTION_CODE (rhs) == BUILT_IN_CONSTANT_P)
return 0;
cost += 20;
break;
case MULT_EXPR:
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
case EXACT_DIV_EXPR:
case CEIL_MOD_EXPR:
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
case TRUNC_MOD_EXPR:
cost += 20;
break;
default:
break;
}
return cost;
}
static bool
determine_max_movement (tree stmt, bool must_preserve_exec)
{
basic_block bb = bb_for_stmt (stmt);
struct loop *loop = bb->loop_father;
struct loop *level;
struct lim_aux_data *lim_data = LIM_DATA (stmt);
use_optype uses;
vuse_optype vuses;
vdef_optype vdefs;
stmt_ann_t ann = stmt_ann (stmt);
unsigned i;
if (must_preserve_exec)
level = ALWAYS_EXECUTED_IN (bb);
else
level = superloop_at_depth (loop, 1);
lim_data->max_loop = level;
uses = USE_OPS (ann);
for (i = 0; i < NUM_USES (uses); i++)
if (!add_dependency (USE_OP (uses, i), lim_data, loop, true))
return false;
vuses = VUSE_OPS (ann);
for (i = 0; i < NUM_VUSES (vuses); i++)
if (!add_dependency (VUSE_OP (vuses, i), lim_data, loop, false))
return false;
vdefs = VDEF_OPS (ann);
for (i = 0; i < NUM_VDEFS (vdefs); i++)
if (!add_dependency (VDEF_OP (vdefs, i), lim_data, loop, false))
return false;
lim_data->cost += stmt_cost (stmt);
return true;
}
static void
set_level (tree stmt, struct loop *orig_loop, struct loop *level)
{
struct loop *stmt_loop = bb_for_stmt (stmt)->loop_father;
struct depend *dep;
stmt_loop = find_common_loop (orig_loop, stmt_loop);
if (LIM_DATA (stmt) && LIM_DATA (stmt)->tgt_loop)
stmt_loop = find_common_loop (stmt_loop,
LIM_DATA (stmt)->tgt_loop->outer);
if (flow_loop_nested_p (stmt_loop, level))
return;
if (!LIM_DATA (stmt))
abort ();
if (level != LIM_DATA (stmt)->max_loop
&& !flow_loop_nested_p (LIM_DATA (stmt)->max_loop, level))
abort ();
LIM_DATA (stmt)->tgt_loop = level;
for (dep = LIM_DATA (stmt)->depends; dep; dep = dep->next)
set_level (dep->stmt, orig_loop, level);
}
static void
set_profitable_level (tree stmt)
{
set_level (stmt, bb_for_stmt (stmt)->loop_father, LIM_DATA (stmt)->max_loop);
}
static bool
nonpure_call_p (tree stmt)
{
if (TREE_CODE (stmt) == MODIFY_EXPR)
stmt = TREE_OPERAND (stmt, 1);
return (TREE_CODE (stmt) == CALL_EXPR
&& TREE_SIDE_EFFECTS (stmt));
}
static void
free_lim_aux_data (struct lim_aux_data *data)
{
struct depend *dep, *next;
for (dep = data->depends; dep; dep = next)
{
next = dep->next;
free (dep);
}
free (data);
}
static void
determine_invariantness_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED,
basic_block bb)
{
enum move_pos pos;
block_stmt_iterator bsi;
tree stmt;
bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL;
struct loop *outermost = ALWAYS_EXECUTED_IN (bb);
if (!bb->loop_father->outer)
return;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Basic block %d (loop %d -- depth %d):\n\n",
bb->index, bb->loop_father->num, bb->loop_father->depth);
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
stmt = bsi_stmt (bsi);
pos = movement_possibility (stmt);
if (pos == MOVE_IMPOSSIBLE)
{
if (nonpure_call_p (stmt))
{
maybe_never = true;
outermost = NULL;
}
continue;
}
stmt_ann (stmt)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
LIM_DATA (stmt)->always_executed_in = outermost;
if (maybe_never && pos == MOVE_PRESERVE_EXECUTION)
continue;
if (!determine_max_movement (stmt, pos == MOVE_PRESERVE_EXECUTION))
{
LIM_DATA (stmt)->max_loop = NULL;
continue;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
print_generic_stmt_indented (dump_file, stmt, 0, 2);
fprintf (dump_file, " invariant up to level %d, cost %d.\n\n",
LIM_DATA (stmt)->max_loop->depth,
LIM_DATA (stmt)->cost);
}
if (LIM_DATA (stmt)->cost >= LIM_EXPENSIVE)
set_profitable_level (stmt);
}
}
static void
determine_invariantness (void)
{
struct dom_walk_data walk_data;
memset (&walk_data, 0, sizeof (struct dom_walk_data));
walk_data.before_dom_children_before_stmts = determine_invariantness_stmt;
init_walk_dominator_tree (&walk_data);
walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
fini_walk_dominator_tree (&walk_data);
}
void
loop_commit_inserts (void)
{
unsigned old_last_basic_block, i;
basic_block bb;
old_last_basic_block = last_basic_block;
bsi_commit_edge_inserts (NULL);
for (i = old_last_basic_block; i < (unsigned) last_basic_block; i++)
{
bb = BASIC_BLOCK (i);
add_bb_to_loop (bb,
find_common_loop (bb->succ->dest->loop_father,
bb->pred->src->loop_father));
}
}
static void
move_computations_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED,
basic_block bb)
{
struct loop *level;
block_stmt_iterator bsi;
tree stmt;
unsigned cost = 0;
if (!bb->loop_father->outer)
return;
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
stmt = bsi_stmt (bsi);
if (!LIM_DATA (stmt))
{
bsi_next (&bsi);
continue;
}
cost = LIM_DATA (stmt)->cost;
level = LIM_DATA (stmt)->tgt_loop;
free_lim_aux_data (LIM_DATA (stmt));
stmt_ann (stmt)->common.aux = NULL;
if (!level)
{
bsi_next (&bsi);
continue;
}
if (TREE_CODE (stmt) == COND_EXPR)
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Moving statement\n");
print_generic_stmt (dump_file, stmt, 0);
fprintf (dump_file, "(cost %u) out of loop %d.\n\n",
cost, level->num);
}
bsi_insert_on_edge (loop_preheader_edge (level), stmt);
bsi_remove (&bsi);
}
}
static void
move_computations (void)
{
struct dom_walk_data walk_data;
memset (&walk_data, 0, sizeof (struct dom_walk_data));
walk_data.before_dom_children_before_stmts = move_computations_stmt;
init_walk_dominator_tree (&walk_data);
walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
fini_walk_dominator_tree (&walk_data);
loop_commit_inserts ();
rewrite_into_ssa (false);
if (bitmap_first_set_bit (vars_to_rename) >= 0)
{
rewrite_into_loop_closed_ssa ();
}
bitmap_clear (vars_to_rename);
}
static bool
may_move_till (tree base ATTRIBUTE_UNUSED, tree *index, void *data)
{
struct loop *loop = data, *max_loop;
if (TREE_CODE (*index) != SSA_NAME)
return true;
max_loop = outermost_invariant_loop (*index, loop);
if (!max_loop)
return false;
if (loop == max_loop
|| flow_loop_nested_p (max_loop, loop))
return true;
return false;
}
static bool
force_move_till (tree base ATTRIBUTE_UNUSED, tree *index, void *data)
{
tree stmt;
if (TREE_CODE (*index) != SSA_NAME)
return true;
stmt = SSA_NAME_DEF_STMT (*index);
if (IS_EMPTY_STMT (stmt))
return true;
set_level (stmt, bb_for_stmt (stmt)->loop_father, data);
return true;
}
static void
record_use (struct use **uses, tree stmt, tree *addr)
{
struct use *use = xmalloc (sizeof (struct use));
use->stmt = stmt;
use->addr = addr;
use->next = *uses;
*uses = use;
}
static void
free_uses (struct use *uses)
{
struct use *act;
while (uses)
{
act = uses;
uses = uses->next;
free (act);
}
}
static tree
single_reachable_address (struct loop *loop, tree stmt, struct use **uses)
{
tree *queue = xmalloc (sizeof (tree) * max_uid);
sbitmap seen = sbitmap_alloc (max_uid);
tree addr = NULL, *aaddr;
unsigned in_queue = 1;
dataflow_t df;
unsigned i, n;
sbitmap_zero (seen);
*uses = NULL;
queue[0] = stmt;
SET_BIT (seen, stmt_ann (stmt)->uid);
while (in_queue)
{
stmt = queue[--in_queue];
if (LIM_DATA (stmt)
&& LIM_DATA (stmt)->sm_done)
goto fail;
switch (TREE_CODE (stmt))
{
case MODIFY_EXPR:
aaddr = &TREE_OPERAND (stmt, 0);
if (is_gimple_reg (*aaddr)
|| !is_gimple_lvalue (*aaddr))
aaddr = &TREE_OPERAND (stmt, 1);
if (is_gimple_reg (*aaddr)
|| !is_gimple_lvalue (*aaddr)
|| (addr && !operand_equal_p (*aaddr, addr, 0)))
goto fail;
addr = *aaddr;
record_use (uses, stmt, aaddr);
case PHI_NODE:
df = get_immediate_uses (stmt);
n = num_immediate_uses (df);
for (i = 0; i < n; i++)
{
stmt = immediate_use (df, i);
if (!flow_bb_inside_loop_p (loop, bb_for_stmt (stmt)))
continue;
if (TEST_BIT (seen, stmt_ann (stmt)->uid))
continue;
SET_BIT (seen, stmt_ann (stmt)->uid);
queue[in_queue++] = stmt;
}
break;
default:
goto fail;
}
}
free (queue);
sbitmap_free (seen);
return addr;
fail:
free_uses (*uses);
*uses = NULL;
free (queue);
sbitmap_free (seen);
return NULL;
}
static void
rewrite_uses (tree tmp_var, struct use *uses)
{
vdef_optype vdefs;
vuse_optype vuses;
unsigned i;
tree var;
for (; uses; uses = uses->next)
{
vdefs = STMT_VDEF_OPS (uses->stmt);
for (i = 0; i < NUM_VDEFS (vdefs); i++)
{
var = SSA_NAME_VAR (VDEF_RESULT (vdefs, i));
bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
}
vuses = STMT_VUSE_OPS (uses->stmt);
for (i = 0; i < NUM_VUSES (vuses); i++)
{
var = SSA_NAME_VAR (VUSE_OP (vuses, i));
bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
}
*uses->addr = tmp_var;
modify_stmt (uses->stmt);
}
}
static void
schedule_sm (struct loop *loop, edge *exits, unsigned n_exits, tree addr,
struct use *uses)
{
struct use *use;
tree tmp_var;
unsigned i;
tree load, store;
tmp_var = create_tmp_var (TREE_TYPE (addr), "lsm_tmp");
add_referenced_tmp_var (tmp_var);
bitmap_set_bit (vars_to_rename, var_ann (tmp_var)->uid);
for_each_index (&addr, force_move_till, loop);
rewrite_uses (tmp_var, uses);
for (use = uses; use; use = use->next)
if (LIM_DATA (use->stmt))
LIM_DATA (use->stmt)->sm_done = true;
load = build (MODIFY_EXPR, void_type_node, tmp_var, addr);
modify_stmt (load);
stmt_ann (load)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
LIM_DATA (load)->max_loop = loop;
LIM_DATA (load)->tgt_loop = loop;
bsi_insert_on_edge (loop_latch_edge (loop), load);
for (i = 0; i < n_exits; i++)
{
store = build (MODIFY_EXPR, void_type_node,
unshare_expr (addr), tmp_var);
bsi_insert_on_edge (exits[i], store);
}
}
static void
determine_lsm_reg (struct loop *loop, edge *exits, unsigned n_exits, tree reg)
{
tree addr;
struct use *uses, *use;
struct loop *must_exec;
if (is_gimple_reg (reg))
return;
addr = single_reachable_address (loop, SSA_NAME_DEF_STMT (reg), &uses);
if (!addr)
return;
if (!for_each_index (&addr, may_move_till, loop))
{
free_uses (uses);
return;
}
if (unsafe_memory_access_p (addr))
{
for (use = uses; use; use = use->next)
{
if (!LIM_DATA (use->stmt))
continue;
must_exec = LIM_DATA (use->stmt)->always_executed_in;
if (!must_exec)
continue;
if (must_exec == loop
|| flow_loop_nested_p (must_exec, loop))
break;
}
if (!use)
{
free_uses (uses);
return;
}
}
schedule_sm (loop, exits, n_exits, addr, uses);
free_uses (uses);
}
static bool
loop_suitable_for_sm (struct loop *loop ATTRIBUTE_UNUSED, edge *exits, unsigned n_exits)
{
unsigned i;
for (i = 0; i < n_exits; i++)
if (exits[i]->flags & EDGE_ABNORMAL)
return false;
return true;
}
static void
determine_lsm_loop (struct loop *loop)
{
tree phi;
unsigned n_exits;
edge *exits = get_loop_exit_edges (loop, &n_exits);
if (!loop_suitable_for_sm (loop, exits, n_exits))
{
free (exits);
return;
}
for (phi = phi_nodes (loop->header); phi; phi = TREE_CHAIN (phi))
determine_lsm_reg (loop, exits, n_exits, PHI_RESULT (phi));
free (exits);
}
static void
determine_lsm (struct loops *loops)
{
struct loop *loop;
basic_block bb;
max_uid = 0;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
tree phi;
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
stmt_ann (bsi_stmt (bsi))->uid = max_uid++;
for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
stmt_ann (phi)->uid = max_uid++;
}
compute_immediate_uses (TDFA_USE_VOPS, NULL);
loop = loops->tree_root->inner;
while (1)
{
determine_lsm_loop (loop);
if (loop->inner)
{
loop = loop->inner;
continue;
}
while (!loop->next)
{
loop = loop->outer;
if (loop == loops->tree_root)
{
free_df ();
loop_commit_inserts ();
return;
}
}
loop = loop->next;
}
}
static void
fill_always_executed_in (struct loop *loop, sbitmap contains_call)
{
basic_block bb = NULL, *bbs, last = NULL;
unsigned i;
edge e;
struct loop *inn_loop = loop;
if (!loop->header->aux)
{
bbs = get_loop_body_in_dom_order (loop);
for (i = 0; i < loop->num_nodes; i++)
{
bb = bbs[i];
if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
last = bb;
if (TEST_BIT (contains_call, bb->index))
break;
for (e = bb->succ; e; e = e->succ_next)
if (!flow_bb_inside_loop_p (loop, e->dest))
break;
if (e)
break;
if (bb->flags & BB_IRREDUCIBLE_LOOP)
break;
if (!flow_bb_inside_loop_p (inn_loop, bb))
break;
if (bb->loop_father->header == bb)
{
if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
break;
inn_loop = bb->loop_father;
}
}
while (1)
{
last->aux = loop;
if (last == loop->header)
break;
last = get_immediate_dominator (CDI_DOMINATORS, last);
}
free (bbs);
}
for (loop = loop->inner; loop; loop = loop->next)
fill_always_executed_in (loop, contains_call);
}
static void
tree_ssa_lim_initialize (struct loops *loops)
{
sbitmap contains_call = sbitmap_alloc (last_basic_block);
block_stmt_iterator bsi;
struct loop *loop;
basic_block bb;
sbitmap_zero (contains_call);
FOR_EACH_BB (bb)
{
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
if (nonpure_call_p (bsi_stmt (bsi)))
break;
}
if (!bsi_end_p (bsi))
SET_BIT (contains_call, bb->index);
}
for (loop = loops->tree_root->inner; loop; loop = loop->next)
fill_always_executed_in (loop, contains_call);
sbitmap_free (contains_call);
}
static void
tree_ssa_lim_finalize (void)
{
basic_block bb;
FOR_EACH_BB (bb)
{
bb->aux = NULL;
}
}
void
tree_ssa_lim (struct loops *loops)
{
tree_ssa_lim_initialize (loops);
determine_invariantness ();
determine_lsm (loops);
move_computations ();
tree_ssa_lim_finalize ();
}