operation on the same variable. */
gimple *shift_after_xor;
- /* Phi statements result may be the crc variable. */
+ /* Phi statement, result may be the crc variable. */
gimple *first_phi_for_crc;
/* Sometimes polynomial may not be constant
The result of phi statement may contain the polynomial. */
gimple *second_phi_for_crc;
+ /* Phi statement, result maybe data (if exists). */
+ gimple * data;
+
+ /* The loop, which probably calculates CRC. */
+ loop *crc_loop;
+
unsigned HOST_WIDE_INT loop_iteration_number;
/* Function's return value size. */
shift_after_xor = nullptr;
first_phi_for_crc = nullptr;
second_phi_for_crc = nullptr;
+ data = nullptr;
is_left_shift = false;
crc_if_dep = false;
clean_xor_maybe_crc = true;
/* This function goes up through the def-chain of the name,
until doesn't encounter a phi statement or
if it does not meet certain conditions
- depending on the passed check_dependency function.
- The check_dependency may be the check_def_stmt_for_xor
+ depending on the passed continue_to_check_dep function.
+ The continue_to_check_dep may be the check_def_stmt_for_xor
or check_def_stmt_for_if function. */
void
- get_dep (tree name, void (crc_optimization::*check_dependency) (tree ssa));
-
- /* Check whether the statement, dependent from xor's operands,
- does shift operation (for calculating crc)
- or is a phi statement. */
- void check_def_stmt_for_xor (tree ssa);
-
- /* Walks through def-chain of if's condition and
- checks whether if's condition and xor-ed variable
+ get_dep (tree name,
+ bool (crc_optimization::*continue_to_check_dep) (gimple* stmt));
+
+/* Checks whether the def_stmt statement, dependent from xor's operands,
+ does shift operation for calculating crc
+ or is a phi statement. Keeps phi statements of the loop's header.
+ Returns false, if there is an instruction which may not exist
+ in the CRC loop.
+ Returns true, if the def-chain examination must be continued. */
+ bool continue_to_check_dep_for_xor (gimple* stmt);
+
+/* Checks whether if's condition and xor-ed variable
are dependent from the same variable.
- (The crc variable is xor-ed if variable's MSB/LSB is 1). */
- void check_def_stmt_for_if (tree ssa);
+ (The crc variable is xor-ed if variable's MSB/LSB is 1).
+ Also determines phi instruction's of data and crc
+ (for further polynomial extraction). */
+ bool continue_to_check_dep_for_if (gimple* stmt);
/* This function checks that xor is done under the condition
of MSB/LSB being one.
};
-/* Set GIMPLE_PHI and GIMPLE statements of the function not visited. */
+/* Set GIMPLE_PHI and GIMPLE statements of the crc loop not visited. */
+void
+set_loop_statements_not_visited (loop *loop)
+{
+ basic_block *bbs = get_loop_body_in_dom_order (loop);
+ for (unsigned int i = 0; i < loop->num_nodes; i++)
+ {
+ basic_block bb = bbs[i];
+ /* Set phis not visited. */
+ for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ {
+ gphi *stmt = gsi.phi ();
+ gimple_set_visited (stmt, false);
+ }
+ /* Set statements not visited. */
+ for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ {
+ gimple *stmt = gsi_stmt (gsi);
+ gimple_set_visited (stmt, false);
+ }
+ }
+}
+
+/* Set GIMPLE_PHI and GIMPLE statements of the function not visited. */
static void
set_all_statements_not_visited (function *fun)
{
}
/* Check whether there is a dependence between
- if condition's variable and xor-ed variable. */
+ if condition's variable and xor-ed variable.
+ Also determine phi statements of crc and data. */
tree lhs = gimple_cond_lhs (cond);
tree rhs = gimple_cond_rhs (cond);
+ set_loop_statements_not_visited (crc_loop);
if (TREE_CODE (lhs) == SSA_NAME)
- check_def_stmt_for_if (lhs);
+ get_dep (lhs, &crc_optimization::continue_to_check_dep_for_if);
else if (TREE_CODE (rhs) == SSA_NAME)
- check_def_stmt_for_if (rhs);
+ get_dep (rhs, &crc_optimization::continue_to_check_dep_for_if);
else
return false; /* Both parts of condition are not SSA_NAME. */
/* This function goes up through the def-chain of the given name,
until doesn't encounter a phi statement or
if it does not meet certain conditions
- depending on the passed check_dependency function.
- The check_dependency may be the check_def_stmt_for_xor
+ depending on the passed continue_to_check_dep function.
+ The continue_to_check_dep may be the check_def_stmt_for_xor
or check_def_stmt_for_if function. */
void
crc_optimization::get_dep (tree name,
- void (crc_optimization::*check_dependency) (
- tree ssa))
+ bool (crc_optimization::*continue_to_check_dep) (
+ gimple* ssa))
{
- if (!clean_xor_maybe_crc)
+ if (!(name && TREE_CODE (name) == SSA_NAME))
return;
- tree ssa1 = NULL_TREE, ssa2 = NULL_TREE;
-
/* No definition chain for default defs. */
if (SSA_NAME_IS_DEFAULT_DEF (name))
return;
gimple *stmt = SSA_NAME_DEF_STMT (name);
- /* If it is an assigment statement - get first and second operand
- if phi statement of loop's header bb - stop function's execution. */
+ if (!stmt)
+ return;
+
+ /* Don't go outside the loop. */
+ if (!flow_bb_inside_loop_p (crc_loop, gimple_bb (stmt)))
+ return;
+
+ /* Check the statement, extract important information.
+ Stop examining def-chain if there is no need of other information. */
+ if (!((this->*continue_to_check_dep) (stmt)))
+ return;
+
+ /* If it is an assigment statement,
+ get and check def-chain for the first and second operands.
+ Otherwise if it's a phi statement, not declared in loop's header,
+ get and check def-chain for its values. */
if (is_a<gassign *> (stmt))
{
- ssa1 = gimple_assign_rhs1 (stmt);
- ssa2 = gimple_assign_rhs2 (stmt);
+ tree ssa1 = gimple_assign_rhs1 (stmt);
+ tree ssa2 = gimple_assign_rhs2 (stmt);
+
+ get_dep (ssa1, continue_to_check_dep);
+ get_dep (ssa2, continue_to_check_dep);
}
- else if (is_a<gphi *> (stmt)
- && (!bb_loop_header_p (gimple_bb (stmt))))
+ else if (is_a<gphi *> (stmt) && !bb_loop_header_p (gimple_bb (stmt)))
{
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "Phi's definition IS NOT in loop header.\n");
-
- if (check_dependency == &crc_optimization::check_def_stmt_for_xor)
- clean_xor_maybe_crc = false;
- return;
+ for (unsigned i = 0; i < gimple_phi_num_args (stmt); i++)
+ {
+ tree val = gimple_phi_arg_def (stmt, i);
+ get_dep (val, continue_to_check_dep);
+ }
}
-
- /* Do some checks on definition statements of
- assignment's first and second operands. */
- (this->*check_dependency) (ssa1);
- (this->*check_dependency) (ssa2);
- return;
}
-/* Check whether the statement, dependent from xor's operands,
- does shift operation (for calculating crc)
- or is a phi statement. */
+/* Checks whether the def_stmt statement, dependent from xor's operands,
+ does shift operation for calculating crc
+ or is a phi statement. Keeps phi statements of the loop's header.
-void
-crc_optimization::check_def_stmt_for_xor (tree dep)
+ Returns false, if there is an instruction which may not exist
+ in the CRC loop.
+ Returns true, if the def-chain examination must be continued. */
+
+bool
+crc_optimization::continue_to_check_dep_for_xor (gimple *def_stmt)
{
- if (!gimple_range_ssa_p (dep))
- return;
+
if (!clean_xor_maybe_crc)
- return;
+ return false;
- gimple *def_stmt = SSA_NAME_DEF_STMT (dep);
+ if (gimple_visited_p (def_stmt))
+ return false;
- if (!def_stmt)
- return;
+ gimple_set_visited (def_stmt, true);
if (is_gimple_assign (def_stmt))
- if (can_not_be_shift_of_crc (def_stmt, true))
- return;
-
- /* Keep phi statement. */
- if (is_a<gphi *> (def_stmt))
{
- if (first_phi_for_crc)
+ if (can_not_be_shift_of_crc (def_stmt, true))
{
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Set second phi.\n");
-
- second_phi_for_crc = def_stmt;
+ clean_xor_maybe_crc = false;
+ return false;
}
- else
+ }
+ else if (is_a<gphi *> (def_stmt))
+ {
+ /* Keep phi statement. */
+ if (bb_loop_header_p (gimple_bb (def_stmt)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Set first phi.\n");
+ fprintf (dump_file,
+ "Phi's definition is in loop header.\n");
- first_phi_for_crc = def_stmt;
+ /* The case when polynomial's value is determined by
+ a phi statement. */
+ if (first_phi_for_crc)
+ {
+ second_phi_for_crc = def_stmt;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Set second phi.\n");
+ }
+ else
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Set first phi.\n");
+ first_phi_for_crc = def_stmt;
+ }
+ return true;
}
- return;
}
-
- /* Get the def chain for the operand. */
- get_dep (dep, &crc_optimization::check_def_stmt_for_xor);
+ return true;
}
-/* Walks through def-chain of if's condition and
- checks whether if's condition and xor-ed variable
+/* Checks whether if's condition and xor-ed variable
are dependent from the same variable.
- (The crc variable is xor-ed if variable's MSB/LSB is 1). */
+ (The crc variable is xor-ed if variable's MSB/LSB is 1).
-void
-crc_optimization::check_def_stmt_for_if (tree dep)
-{
- if (!gimple_range_ssa_p (dep))
- return;
- gimple *def_stmt = SSA_NAME_DEF_STMT (dep);
+ Also determines phi instruction's of data and crc
+ (for further polynomial extraction). */
- if (!def_stmt)
- return;
+bool
+crc_optimization::continue_to_check_dep_for_if (gimple *def_stmt)
+{
+ gimple_set_visited (def_stmt, true);
- /* Checks whether if's condition and xor-ed variable are dependent
- from the same variable. */
- if (is_a<gphi *> (def_stmt))
+ if (is_a<gphi *> (def_stmt) && bb_loop_header_p (gimple_bb (def_stmt)))
{
+ /* Checks whether if's condition and xor-ed variable are dependent
+ from the same variable. */
if ((first_phi_for_crc && first_phi_for_crc == def_stmt)
|| (second_phi_for_crc && second_phi_for_crc == def_stmt))
{
crc_if_dep = true;
+ /* If the second phi equals def_stmt,
+ then it is used for crc calculation,
+ keep crc phi in first_phi_for_crc.
+ (This is needed for the polynomial extraction.) */
+ if ((second_phi_for_crc && second_phi_for_crc == def_stmt))
+ {
+ first_phi_for_crc = second_phi_for_crc;
+ }
+
if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "\nIf condition has dependence "
- "from the same variable as xor.\n");
+ {
+ fprintf (dump_file,
+ "If condition has dependence "
+ "from the same variable as xor.\n"
+ "CRC's phi statement is:\n");
+ print_gimple_stmt (dump_file, def_stmt, dump_flags);
+ }
}
- return;
- }
+ /* If we encounter a phi statement which isn't the crc,
+ then it may be the data.
+ (This is needed for the polynomial extraction.) */
+ else
+ {
+ /* Cond statement for crc calculation
+ may depend only on data and crc.
+ If it doesn't then it's not for crc calculation. */
+ if (data && data != def_stmt)
+ {
+ crc_if_dep = false;
+ return false;
+ }
- /* Get the def chain for the operand. */
- get_dep (dep, &crc_optimization::check_def_stmt_for_if);
+ data = def_stmt;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file,
+ "Found data's phi statement:\n");
+ print_gimple_stmt (dump_file, def_stmt, dump_flags);
+ }
+ }
+ }
+ return true;
}
{
tree crc_var = gimple_assign_lhs (xor_stmt);
set_initial_values ();
+ set_loop_statements_not_visited (crc_loop);
get_dep (crc_var,
- &crc_optimization::check_def_stmt_for_xor);
+ &crc_optimization::continue_to_check_dep_for_xor);
+
+
if (!clean_xor_maybe_crc)
- return false;
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Xor doesn't calculate crc.\n");
+ return false;
+ }
/* Check the case when shift is done after xor. */
if (!shift_before_xor)
{
if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "No shift before xor.\n");
+ fprintf (dump_file, "No shift before xor, trying to find after xor.\n");
+
+ // TODO: It's time consuming to get loop's body,
+ // (set_all_statements_not_visited may be time consuming too).
+ // Do it better.
+ set_loop_statements_not_visited (crc_loop);
- set_all_statements_not_visited (fun);
find_shift_after_xor (crc_loop, crc_var);
if (!shift_after_xor)
return false;
return true;
}
}
+ else
+ {
+ if (dump_file)
+ fprintf (dump_file,
+ "Xor bb doesn't have single predecessor.\n");
+ }
return false;
}
if (!is_loop_of_crc_calculation (loop))
continue;
+ crc_loop = loop;
basic_block *bbs = get_loop_body_in_dom_order (loop);
/* Walk bbs of the loop. */
for (unsigned int i = 0; i < loop->num_nodes; i++)
projects / thirdparty / gcc.git / commitdiff
