eventually one of the phi arguments will be an integer constant. In the
future, this could be extended to also handle simple assignments of
arithmetic operations. */
- if (gimple_code (def_stmt) != GIMPLE_PHI)
+ if (gimple_code (def_stmt) != GIMPLE_PHI
+ || (gimple_phi_num_args (def_stmt)
+ >= (unsigned) PARAM_VALUE (PARAM_FSM_MAXIMUM_PHI_ARGUMENTS)))
return;
/* Avoid infinite recursion. */
/* Iterate over the arguments of PHI. */
unsigned int i;
- for (i = 0; i < gimple_phi_num_args (phi); i++)
+ if (gimple_phi_num_args (phi)
+ < (unsigned) PARAM_VALUE (PARAM_FSM_MAXIMUM_PHI_ARGUMENTS))
{
- tree arg = gimple_phi_arg_def (phi, i);
- basic_block bbi = gimple_phi_arg_edge (phi, i)->src;
-
- /* Skip edges pointing outside the current loop. */
- if (!arg || var_bb->loop_father != bbi->loop_father)
- continue;
-
- if (TREE_CODE (arg) == SSA_NAME)
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
{
- vec_safe_push (path, bbi);
- /* Recursively follow SSA_NAMEs looking for a constant definition. */
- fsm_find_control_statement_thread_paths (arg, visited_bbs, path,
- seen_loop_phi);
+ tree arg = gimple_phi_arg_def (phi, i);
+ basic_block bbi = gimple_phi_arg_edge (phi, i)->src;
- path->pop ();
- continue;
- }
+ /* Skip edges pointing outside the current loop. */
+ if (!arg || var_bb->loop_father != bbi->loop_father)
+ continue;
- if (TREE_CODE (arg) != INTEGER_CST)
- continue;
+ if (TREE_CODE (arg) == SSA_NAME)
+ {
+ vec_safe_push (path, bbi);
+ /* Recursively follow SSA_NAMEs looking for a constant
+ definition. */
+ fsm_find_control_statement_thread_paths (arg, visited_bbs, path,
+ seen_loop_phi);
+
+ path->pop ();
+ continue;
+ }
- /* Note BBI is not in the path yet, hence the +1 in the test below
- to make sure BBI is accounted for in the path length test. */
- int path_length = path->length ();
- if (path_length + 1 > PARAM_VALUE (PARAM_MAX_FSM_THREAD_LENGTH))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "FSM jump-thread path not considered: "
- "the number of basic blocks on the path "
- "exceeds PARAM_MAX_FSM_THREAD_LENGTH.\n");
- continue;
- }
+ if (TREE_CODE (arg) != INTEGER_CST)
+ continue;
- if (max_threaded_paths <= 0)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "FSM jump-thread path not considered: "
- "the number of previously recorded FSM paths to thread "
- "exceeds PARAM_MAX_FSM_THREAD_PATHS.\n");
- continue;
- }
+ /* Note BBI is not in the path yet, hence the +1 in the test below
+ to make sure BBI is accounted for in the path length test. */
+ int path_length = path->length ();
+ if (path_length + 1 > PARAM_VALUE (PARAM_MAX_FSM_THREAD_LENGTH))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "FSM jump-thread path not considered: "
+ "the number of basic blocks on the path "
+ "exceeds PARAM_MAX_FSM_THREAD_LENGTH.\n");
+ continue;
+ }
- /* Add BBI to the path. */
- vec_safe_push (path, bbi);
- ++path_length;
-
- int n_insns = 0;
- gimple_stmt_iterator gsi;
- int j;
- loop_p loop = (*path)[0]->loop_father;
- bool path_crosses_loops = false;
- bool threaded_through_latch = false;
- bool multiway_branch_in_path = false;
- bool threaded_multiway_branch = false;
-
- /* Count the number of instructions on the path: as these instructions
- will have to be duplicated, we will not record the path if there are
- too many instructions on the path. Also check that all the blocks in
- the path belong to a single loop. */
- for (j = 0; j < path_length; j++)
- {
- basic_block bb = (*path)[j];
-
- /* Remember, blocks in the path are stored in opposite order
- in the PATH array. The last entry in the array represents
- the block with an outgoing edge that we will redirect to the
- jump threading path. Thus we don't care about that block's
- loop father, nor how many statements are in that block because
- it will not be copied or whether or not it ends in a multiway
- branch. */
- if (j < path_length - 1)
+ if (max_threaded_paths <= 0)
{
- if (bb->loop_father != loop)
- {
- path_crosses_loops = true;
- break;
- }
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "FSM jump-thread path not considered: "
+ "the number of previously recorded FSM paths to "
+ "thread exceeds PARAM_MAX_FSM_THREAD_PATHS.\n");
+ continue;
+ }
- for (gsi = gsi_after_labels (bb);
- !gsi_end_p (gsi);
- gsi_next_nondebug (&gsi))
+ /* Add BBI to the path. */
+ vec_safe_push (path, bbi);
+ ++path_length;
+
+ int n_insns = 0;
+ gimple_stmt_iterator gsi;
+ int j;
+ loop_p loop = (*path)[0]->loop_father;
+ bool path_crosses_loops = false;
+ bool threaded_through_latch = false;
+ bool multiway_branch_in_path = false;
+ bool threaded_multiway_branch = false;
+
+ /* Count the number of instructions on the path: as these instructions
+ will have to be duplicated, we will not record the path if there
+ are too many instructions on the path. Also check that all the
+ blocks in the path belong to a single loop. */
+ for (j = 0; j < path_length; j++)
+ {
+ basic_block bb = (*path)[j];
+
+ /* Remember, blocks in the path are stored in opposite order
+ in the PATH array. The last entry in the array represents
+ the block with an outgoing edge that we will redirect to the
+ jump threading path. Thus we don't care about that block's
+ loop father, nor how many statements are in that block because
+ it will not be copied or whether or not it ends in a multiway
+ branch. */
+ if (j < path_length - 1)
{
- gimple *stmt = gsi_stmt (gsi);
- /* Do not count empty statements and labels. */
- if (gimple_code (stmt) != GIMPLE_NOP
- && !(gimple_code (stmt) == GIMPLE_ASSIGN
- && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
- && !is_gimple_debug (stmt))
- ++n_insns;
+ if (bb->loop_father != loop)
+ {
+ path_crosses_loops = true;
+ break;
+ }
+
+ for (gsi = gsi_after_labels (bb);
+ !gsi_end_p (gsi);
+ gsi_next_nondebug (&gsi))
+ {
+ gimple *stmt = gsi_stmt (gsi);
+ /* Do not count empty statements and labels. */
+ if (gimple_code (stmt) != GIMPLE_NOP
+ && !(gimple_code (stmt) == GIMPLE_ASSIGN
+ && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
+ && !is_gimple_debug (stmt))
+ ++n_insns;
+ }
+
+ /* We do not look at the block with the threaded branch
+ in this loop. So if any block with a last statement that
+ is a GIMPLE_SWITCH or GIMPLE_GOTO is seen, then we have a
+ multiway branch on our path.
+
+ The block in PATH[0] is special, it's the block were we're
+ going to be able to eliminate its branch. */
+ gimple *last = last_stmt (bb);
+ if (last && (gimple_code (last) == GIMPLE_SWITCH
+ || gimple_code (last) == GIMPLE_GOTO))
+ {
+ if (j == 0)
+ threaded_multiway_branch = true;
+ else
+ multiway_branch_in_path = true;
+ }
}
- /* We do not look at the block with the threaded branch
- in this loop. So if any block with a last statement that
- is a GIMPLE_SWITCH or GIMPLE_GOTO is seen, then we have a
- multiway branch on our path.
-
- The block in PATH[0] is special, it's the block were we're
- going to be able to eliminate its branch. */
- gimple *last = last_stmt (bb);
- if (last && (gimple_code (last) == GIMPLE_SWITCH
- || gimple_code (last) == GIMPLE_GOTO))
- {
- if (j == 0)
- threaded_multiway_branch = true;
- else
- multiway_branch_in_path = true;
- }
+ /* Note if we thread through the latch, we will want to include
+ the last entry in the array when determining if we thread
+ through the loop latch. */
+ if (loop->latch == bb)
+ threaded_through_latch = true;
}
- /* Note if we thread through the latch, we will want to include
- the last entry in the array when determining if we thread
- through the loop latch. */
- if (loop->latch == bb)
- threaded_through_latch = true;
- }
+ gimple *stmt = get_gimple_control_stmt ((*path)[0]);
+ gcc_assert (stmt);
+ /* We have found a constant value for ARG. For GIMPLE_SWITCH
+ and GIMPLE_GOTO, we use it as-is. However, for a GIMPLE_COND
+ we need to substitute, fold and simplify so we can determine
+ the edge taken out of the last block. */
+ if (gimple_code (stmt) == GIMPLE_COND)
+ {
+ enum tree_code cond_code = gimple_cond_code (stmt);
- gimple *stmt = get_gimple_control_stmt ((*path)[0]);
- gcc_assert (stmt);
- /* We have found a constant value for ARG. For GIMPLE_SWITCH
- and GIMPLE_GOTO, we use it as-is. However, for a GIMPLE_COND
- we need to substitute, fold and simplify so we can determine
- the edge taken out of the last block. */
- if (gimple_code (stmt) == GIMPLE_COND)
- {
- enum tree_code cond_code = gimple_cond_code (stmt);
+ /* We know the underyling format of the condition. */
+ arg = fold_binary (cond_code, boolean_type_node,
+ arg, gimple_cond_rhs (stmt));
+ }
- /* We know the underyling format of the condition. */
- arg = fold_binary (cond_code, boolean_type_node,
- arg, gimple_cond_rhs (stmt));
- }
+ /* If this path threaded through the loop latch back into the
+ same loop and the destination does not dominate the loop
+ latch, then this thread would create an irreducible loop.
+
+ We have to know the outgoing edge to figure this out. */
+ edge taken_edge = find_taken_edge ((*path)[0], arg);
+ bool creates_irreducible_loop = false;
+ if (threaded_through_latch
+ && loop == taken_edge->dest->loop_father
+ && (determine_bb_domination_status (loop, taken_edge->dest)
+ == DOMST_NONDOMINATING))
+ creates_irreducible_loop = true;
+
+ /* PHIs in the final target and only the final target will need
+ to be duplicated. So only count those against the number
+ of statements. */
+ gphi_iterator gsip;
+ for (gsip = gsi_start_phis (taken_edge->dest);
+ !gsi_end_p (gsip);
+ gsi_next (&gsip))
+ {
+ gphi *phi = gsip.phi ();
+ tree dst = gimple_phi_result (phi);
+
+ /* We consider any non-virtual PHI as a statement since it
+ count result in a constant assignment or copy
+ operation. */
+ if (!virtual_operand_p (dst))
+ ++n_insns;
+ }
- /* If this path threaded through the loop latch back into the
- same loop and the destination does not dominate the loop
- latch, then this thread would create an irreducible loop.
-
- We have to know the outgoing edge to figure this out. */
- edge taken_edge = find_taken_edge ((*path)[0], arg);
- bool creates_irreducible_loop = false;
- if (threaded_through_latch
- && loop == taken_edge->dest->loop_father
- && (determine_bb_domination_status (loop, taken_edge->dest)
- == DOMST_NONDOMINATING))
- creates_irreducible_loop = true;
-
- /* PHIs in the final target and only the final target will need
- to be duplicated. So only count those against the number
- of statements. */
- gphi_iterator gsip;
- for (gsip = gsi_start_phis (taken_edge->dest);
- !gsi_end_p (gsip);
- gsi_next (&gsip))
- {
- gphi *phi = gsip.phi ();
- tree dst = gimple_phi_result (phi);
-
- /* We consider any non-virtual PHI as a statement since it
- count result in a constant assignment or copy
- operation. */
- if (!virtual_operand_p (dst))
- ++n_insns;
- }
+ if (path_crosses_loops)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "FSM jump-thread path not considered: "
+ "the path crosses loops.\n");
+ path->pop ();
+ continue;
+ }
- if (path_crosses_loops)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "FSM jump-thread path not considered: "
- "the path crosses loops.\n");
- path->pop ();
- continue;
- }
+ if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "FSM jump-thread path not considered: "
+ "the number of instructions on the path "
+ "exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
+ path->pop ();
+ continue;
+ }
- if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "FSM jump-thread path not considered: "
- "the number of instructions on the path "
- "exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
- path->pop ();
- continue;
- }
+ /* We avoid creating irreducible inner loops unless we thread through
+ a multiway branch, in which case we have deemed it worth losing
+ other loop optimizations later.
- /* We avoid creating irreducible inner loops unless we thread through
- a multiway branch, in which case we have deemed it worth losing other
- loop optimizations later.
+ We also consider it worth creating an irreducible inner loop if
+ the number of copied statement is low relative to the length of
+ the path -- in that case there's little the traditional loop
+ optimizer would have done anyway, so an irreducible loop is not
+ so bad. */
+ if (!threaded_multiway_branch && creates_irreducible_loop
+ && (n_insns * PARAM_VALUE (PARAM_FSM_SCALE_PATH_STMTS)
+ > path_length * PARAM_VALUE (PARAM_FSM_SCALE_PATH_BLOCKS)))
- We also consider it worth creating an irreducible inner loop if
- the number of copied statement is low relative to the length of
- the path -- in that case there's little the traditional loop optimizer
- would have done anyway, so an irreducible loop is not so bad. */
- if (!threaded_multiway_branch && creates_irreducible_loop
- && (n_insns * PARAM_VALUE (PARAM_FSM_SCALE_PATH_STMTS)
- > path_length * PARAM_VALUE (PARAM_FSM_SCALE_PATH_BLOCKS)))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "FSM would create irreducible loop without threading "
+ "multiway branch.\n");
+ path->pop ();
+ continue;
+ }
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "FSM would create irreducible loop without threading "
- "multiway branch.\n");
- path->pop ();
- continue;
- }
+ /* When there is a multi-way branch on the path, then threading can
+ explode the CFG due to duplicating the edges for that multi-way
+ branch. So like above, only allow a multi-way branch on the path
+ if we actually thread a multi-way branch. */
+ if (!threaded_multiway_branch && multiway_branch_in_path)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "FSM Thread through multiway branch without threading "
+ "a multiway branch.\n");
+ path->pop ();
+ continue;
+ }
- /* When there is a multi-way branch on the path, then threading can
- explode the CFG due to duplicating the edges for that multi-way
- branch. So like above, only allow a multi-way branch on the path
- if we actually thread a multi-way branch. */
- if (!threaded_multiway_branch && multiway_branch_in_path)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "FSM Thread through multiway branch without threading "
- "a multiway branch.\n");
- path->pop ();
- continue;
- }
+ vec<jump_thread_edge *> *jump_thread_path
+ = new vec<jump_thread_edge *> ();
- vec<jump_thread_edge *> *jump_thread_path
- = new vec<jump_thread_edge *> ();
+ /* Record the edges between the blocks in PATH. */
+ for (j = 0; j < path_length - 1; j++)
+ {
+ edge e = find_edge ((*path)[path_length - j - 1],
+ (*path)[path_length - j - 2]);
+ gcc_assert (e);
+ jump_thread_edge *x = new jump_thread_edge (e, EDGE_FSM_THREAD);
+ jump_thread_path->safe_push (x);
+ }
- /* Record the edges between the blocks in PATH. */
- for (j = 0; j < path_length - 1; j++)
- {
- edge e = find_edge ((*path)[path_length - j - 1],
- (*path)[path_length - j - 2]);
- gcc_assert (e);
- jump_thread_edge *x = new jump_thread_edge (e, EDGE_FSM_THREAD);
+ /* Add the edge taken when the control variable has value ARG. */
+ jump_thread_edge *x
+ = new jump_thread_edge (taken_edge, EDGE_NO_COPY_SRC_BLOCK);
jump_thread_path->safe_push (x);
- }
- /* Add the edge taken when the control variable has value ARG. */
- jump_thread_edge *x
- = new jump_thread_edge (taken_edge, EDGE_NO_COPY_SRC_BLOCK);
- jump_thread_path->safe_push (x);
+ register_jump_thread (jump_thread_path);
+ --max_threaded_paths;
- register_jump_thread (jump_thread_path);
- --max_threaded_paths;
-
- /* Remove BBI from the path. */
- path->pop ();
+ /* Remove BBI from the path. */
+ path->pop ();
+ }
}
/* Remove all the nodes that we added from NEXT_PATH. */
projects / platform / upstream / linaro-gcc.git / commitdiff