static void
tree_if_convert_cond_expr (struct loop *loop, tree stmt, tree cond,
block_stmt_iterator *bsi)
{
tree c, c2;
edge true_edge, false_edge;
gcc_assert (TREE_CODE (stmt) == COND_EXPR);
c = COND_EXPR_COND (stmt);
extract_true_false_edges_from_block (bb_for_stmt (stmt),
&true_edge, &false_edge);
/* Add new condition into destination's predicate list. */
/* If 'c' is true then TRUE_EDGE is taken. */
add_to_dst_predicate_list (loop, true_edge, cond,
unshare_expr (c), bsi);
/* If 'c' is false then FALSE_EDGE is taken. */
c2 = invert_truthvalue (unshare_expr (c));
add_to_dst_predicate_list (loop, false_edge, cond, c2, bsi);
/* Now this conditional statement is redundant. Remove it.
But, do not remove exit condition! Update exit condition
using new condition. */
if (!bb_with_exit_edge_p (loop, bb_for_stmt (stmt)))
{
bsi_remove (bsi, true);
cond = NULL_TREE;
}
return;
}
static void
tree_ssa_forward_propagate_single_use_vars (void)
{
basic_block bb;
cfg_changed = false;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
/* Note we update BSI within the loop as necessary. */
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree stmt = bsi_stmt (bsi);
/* If this statement sets an SSA_NAME to an address,
try to propagate the address into the uses of the SSA_NAME. */
if (TREE_CODE (stmt) == MODIFY_EXPR
&& TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
{
if (forward_propagate_addr_expr (stmt))
bsi_remove (&bsi);
else
bsi_next (&bsi);
}
else if (TREE_CODE (stmt) == COND_EXPR)
{
forward_propagate_into_cond (stmt);
bsi_next (&bsi);
}
else
bsi_next (&bsi);
}
}
if (cfg_changed)
cleanup_tree_cfg ();
}
static void
forward_propagate_into_cond (tree cond_expr)
{
gcc_assert (TREE_CODE (cond_expr) == COND_EXPR);
while (1)
{
tree test_var = NULL_TREE;
tree cond = COND_EXPR_COND (cond_expr);
tree new_cond = forward_propagate_into_cond_1 (cond, &test_var);
/* Return if unsuccessful. */
if (new_cond == NULL_TREE)
break;
/* Dump details. */
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " Replaced '");
print_generic_expr (dump_file, cond, dump_flags);
fprintf (dump_file, "' with '");
print_generic_expr (dump_file, new_cond, dump_flags);
fprintf (dump_file, "'\n");
}
COND_EXPR_COND (cond_expr) = new_cond;
update_stmt (cond_expr);
if (has_zero_uses (test_var))
{
tree def = SSA_NAME_DEF_STMT (test_var);
block_stmt_iterator bsi = bsi_for_stmt (def);
bsi_remove (&bsi);
}
}
}
static void
tree_nrv (void)
{
tree result = DECL_RESULT (current_function_decl);
tree result_type = TREE_TYPE (result);
tree found = NULL;
basic_block bb;
block_stmt_iterator bsi;
struct nrv_data data;
/* If this function does not return an aggregate type in memory, then
there is nothing to do. */
if (!aggregate_value_p (result, current_function_decl))
return;
/* Look through each block for assignments to the RESULT_DECL. */
FOR_EACH_BB (bb)
{
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
tree stmt = bsi_stmt (bsi);
tree ret_expr;
if (TREE_CODE (stmt) == RETURN_EXPR)
{
/* In a function with an aggregate return value, the
gimplifier has changed all non-empty RETURN_EXPRs to
return the RESULT_DECL. */
ret_expr = TREE_OPERAND (stmt, 0);
if (ret_expr)
gcc_assert (ret_expr == result);
}
else if (TREE_CODE (stmt) == MODIFY_EXPR
&& TREE_OPERAND (stmt, 0) == result)
{
ret_expr = TREE_OPERAND (stmt, 1);
/* Now verify that this return statement uses the same value
as any previously encountered return statement. */
if (found != NULL)
{
/* If we found a return statement using a different variable
than previous return statements, then we can not perform
NRV optimizations. */
if (found != ret_expr)
return;
}
else
found = ret_expr;
/* The returned value must be a local automatic variable of the
same type and alignment as the function's result. */
if (TREE_CODE (found) != VAR_DECL
|| TREE_THIS_VOLATILE (found)
|| DECL_CONTEXT (found) != current_function_decl
|| TREE_STATIC (found)
|| TREE_ADDRESSABLE (found)
|| DECL_ALIGN (found) > DECL_ALIGN (result)
|| !lang_hooks.types_compatible_p (TREE_TYPE (found),
result_type))
return;
}
}
}
if (!found)
return;
/* If dumping details, then note once and only the NRV replacement. */
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "NRV Replaced: ");
print_generic_expr (dump_file, found, dump_flags);
fprintf (dump_file, " with: ");
print_generic_expr (dump_file, result, dump_flags);
fprintf (dump_file, "\n");
}
/* At this point we know that all the return statements return the
same local which has suitable attributes for NRV. Copy debugging
information from FOUND to RESULT. */
DECL_NAME (result) = DECL_NAME (found);
DECL_SOURCE_LOCATION (result) = DECL_SOURCE_LOCATION (found);
DECL_ABSTRACT_ORIGIN (result) = DECL_ABSTRACT_ORIGIN (found);
TREE_ADDRESSABLE (result) = TREE_ADDRESSABLE (found);
/* Now walk through the function changing all references to VAR to be
RESULT. */
data.var = found;
data.result = result;
FOR_EACH_BB (bb)
{
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree *tp = bsi_stmt_ptr (bsi);
/* If this is a copy from VAR to RESULT, remove it. */
if (TREE_CODE (*tp) == MODIFY_EXPR
&& TREE_OPERAND (*tp, 0) == result
&& TREE_OPERAND (*tp, 1) == found)
bsi_remove (&bsi);
else
{
walk_tree (tp, finalize_nrv_r, &data, 0);
bsi_next (&bsi);
}
}
}
/* FOUND is no longer used. Ensure it gets removed. */
var_ann (found)->used = 0;
}
static void
substitute_single_use_vars (varray_type *cond_worklist,
varray_type vars_worklist)
{
while (VARRAY_ACTIVE_SIZE (vars_worklist) > 0)
{
tree test_var = VARRAY_TOP_TREE (vars_worklist);
tree def = SSA_NAME_DEF_STMT (test_var);
dataflow_t df;
int j, num_uses, propagated_uses;
VARRAY_POP (vars_worklist);
/* Now compute the immediate uses of TEST_VAR. */
df = get_immediate_uses (def);
num_uses = num_immediate_uses (df);
propagated_uses = 0;
/* If TEST_VAR is used more than once and is not a boolean set
via TRUTH_NOT_EXPR with another SSA_NAME as its argument, then
we can not optimize. */
if (num_uses == 1
|| (TREE_CODE (TREE_TYPE (test_var)) == BOOLEAN_TYPE
&& TREE_CODE (TREE_OPERAND (def, 1)) == TRUTH_NOT_EXPR
&& (TREE_CODE (TREE_OPERAND (TREE_OPERAND (def, 1), 0))
== SSA_NAME)))
;
else
continue;
/* Walk over each use and try to forward propagate the RHS of
DEF into the use. */
for (j = 0; j < num_uses; j++)
{
tree cond_stmt;
tree cond;
enum tree_code cond_code;
tree def_rhs;
enum tree_code def_rhs_code;
tree new_cond;
cond_stmt = immediate_use (df, j);
/* For now we can only propagate into COND_EXPRs. */
if (TREE_CODE (cond_stmt) != COND_EXPR)
continue;
cond = COND_EXPR_COND (cond_stmt);
cond_code = TREE_CODE (cond);
def_rhs = TREE_OPERAND (def, 1);
def_rhs_code = TREE_CODE (def_rhs);
/* If the definition of the single use variable was from an
arithmetic operation, then we just need to adjust the
constant in the COND_EXPR_COND and update the variable tested. */
if (def_rhs_code == PLUS_EXPR || def_rhs_code == MINUS_EXPR)
{
tree op0 = TREE_OPERAND (def_rhs, 0);
tree op1 = TREE_OPERAND (def_rhs, 1);
enum tree_code new_code;
tree t;
/* If the variable was defined via X + C, then we must subtract
C from the constant in the conditional. Otherwise we add
C to the constant in the conditional. The result must fold
into a valid gimple operand to be optimizable. */
new_code = def_rhs_code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR;
t = int_const_binop (new_code, TREE_OPERAND (cond, 1), op1, 0);
if (!is_gimple_val (t))
continue;
new_cond = build (cond_code, boolean_type_node, op0, t);
}
/* If the variable is defined by a conditional expression... */
else if (TREE_CODE_CLASS (def_rhs_code) == tcc_comparison)
{
/* TEST_VAR was set from a relational operator. */
tree op0 = TREE_OPERAND (def_rhs, 0);
tree op1 = TREE_OPERAND (def_rhs, 1);
new_cond = build (def_rhs_code, boolean_type_node, op0, op1);
/* Invert the conditional if necessary. */
if ((cond_code == EQ_EXPR
&& integer_zerop (TREE_OPERAND (cond, 1)))
|| (cond_code == NE_EXPR
&& integer_onep (TREE_OPERAND (cond, 1))))
{
new_cond = invert_truthvalue (new_cond);
/* If we did not get a simple relational expression or
bare SSA_NAME, then we can not optimize this case. */
if (!COMPARISON_CLASS_P (new_cond)
&& TREE_CODE (new_cond) != SSA_NAME)
continue;
}
}
else
{
bool invert = false;
enum tree_code new_code;
tree new_arg;
/* TEST_VAR was set from a TRUTH_NOT_EXPR or a NOP_EXPR. */
if (def_rhs_code == TRUTH_NOT_EXPR)
invert = true;
/* If we don't have <NE_EXPR/EQ_EXPR x INT_CST>, then we cannot
optimize this case. */
if ((cond_code == NE_EXPR || cond_code == EQ_EXPR)
&& TREE_CODE (TREE_OPERAND (cond, 1)) != INTEGER_CST)
continue;
if (cond_code == SSA_NAME
|| (cond_code == NE_EXPR
&& integer_zerop (TREE_OPERAND (cond, 1)))
|| (cond_code == EQ_EXPR
&& integer_onep (TREE_OPERAND (cond, 1))))
new_code = NE_EXPR;
else
new_code = EQ_EXPR;
if (invert)
new_code = (new_code == EQ_EXPR ? NE_EXPR : EQ_EXPR);
new_arg = TREE_OPERAND (def_rhs, 0);
new_cond = build2 (new_code, boolean_type_node, new_arg,
fold_convert (TREE_TYPE (new_arg),
integer_zero_node));
}
/* Dump details. */
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " Replaced '");
print_generic_expr (dump_file, cond, dump_flags);
fprintf (dump_file, "' with '");
print_generic_expr (dump_file, new_cond, dump_flags);
fprintf (dump_file, "'\n");
}
/* Replace the condition. */
COND_EXPR_COND (cond_stmt) = new_cond;
modify_stmt (cond_stmt);
propagated_uses++;
VARRAY_PUSH_TREE (*cond_worklist, cond_stmt);
}
/* If we propagated into all the uses, then we can delete DEF.
Unfortunately, we have to find the defining statement in
whatever block it might be in. */
if (num_uses && num_uses == propagated_uses)
{
block_stmt_iterator bsi = bsi_for_stmt (def);
bsi_remove (&bsi);
}
}
}
