#include "set.h"
#include "bitset.h"
#include "bitfiddle.h"
+#include "irhooks.h"
#define MAX_DEPTH 20
static firm_dbg_module_t *dbg;
/**
- * A simple check for sde effects upton an opcode of a ir node.
+ * A simple check for side effects upto an opcode of a ir node.
* @param irn The ir node to check,
* @return 1 if the opcode itself may produce side effects, 0 if not.
*/
static INLINE int has_side_effects(const ir_node *irn)
{
- opcode opc = get_irn_opcode(irn);
+ ir_op *op = get_irn_op(irn);
- if(opc == iro_Cmp)
+ if (op == op_Cmp)
return 0;
return !mode_is_datab(get_irn_mode(irn));
}
+enum failure_reason_t {
+ SUCCESS = IF_RESULT_SUCCESS,
+ TO_DEEP = IF_RESULT_TOO_DEEP,
+ SIDE_EFFECTS = IF_RESULT_SIDE_EFFECT,
+ PHI_FOUND = IF_RESULT_SIDE_EFFECT_PHI
+};
+
/**
- * Decdies, if a given expression and its subexpressions
+ * Decides, if a given expression and its subexpressions
* (to certain, also given extent) can be moved to a block.
- * @param expr The expression to examine.
- * @param block The block where the expression should go.
- * @param depth The current depth, passed recursively. Use 0 for
- * non-recursive calls.
+ *
+ * @param expr The expression to examine.
+ * @param block The block where the expression should go.
+ * @param depth The current depth, passed recursively. Use 0 for
+ * non-recursive calls.
* @param max_depth The maximum depth to which the expression should be
* examined.
+ *
+ * @return a failure reason
*/
static int _can_move_to(ir_node *expr, ir_node *dest_block, int depth, int max_depth)
{
int i, n;
- int res = 1;
+ int res = SUCCESS;
ir_node *expr_block = get_nodes_block(expr);
-
/*
* If we are forced to look too deep into the expression,
* treat it like it could not be moved.
*/
if(depth >= max_depth) {
- res = 0;
+ res = TO_DEEP;
goto end;
}
* has side effects or anything else. It is executed on each
* path the destination block is reached.
*/
- if(block_dominates(expr_block, dest_block))
+ if (block_dominates(expr_block, dest_block))
goto end;
/*
* We cannot move phis!
*/
- if(is_Phi(expr)) {
- res = 0;
+ if (is_Phi(expr)) {
+ res = PHI_FOUND;
goto end;
}
/*
- * This should be superflous and could be converted into a assertion.
+ * This should be superfluous and could be converted into a assertion.
* The destination block _must_ dominate the block of the expression,
* else the expression could be used without its definition.
*/
- if(!block_dominates(dest_block, expr_block)) {
- res = 0;
+ if (! block_dominates(dest_block, expr_block)) {
+ res = IF_RESULT_SIDE_EFFECT;
goto end;
}
/*
* Surely, if the expression does not have a data mode, it is not
- * movable. Perhaps onw should also test the floating property of
+ * movable. Perhaps one should also test the floating property of
* the opcode/node.
*/
- if(has_side_effects(expr)) {
- res = 0;
+ if (has_side_effects(expr)) {
+ res = IF_RESULT_SIDE_EFFECT;
goto end;
}
* check them out. If one of them cannot be moved, this one
* cannot be moved either.
*/
- for(i = 0, n = get_irn_arity(expr); i < n; ++i) {
+ for (i = 0, n = get_irn_arity(expr); i < n; ++i) {
ir_node *op = get_irn_n(expr, i);
int new_depth = is_Proj(op) ? depth : depth + 1;
- if(!_can_move_to(op, dest_block, new_depth, max_depth)) {
- res = 0;
+
+ res = _can_move_to(op, dest_block, new_depth, max_depth);
+
+ if (res != SUCCESS)
goto end;
- }
}
end:
* deeper into an expression than a given threshold to examine if
* it can be moved, the expression is rejected and the test returns
* false.
- * @param expr The expression to check for.
+ *
+ * @param expr The expression to check for.
* @param dest_block The destination block you want @p expr to be.
- * @param max_depth The maximum depth @p expr should be investigated.
- * @return 1, if the expression can be moved to the destination block,
- * 0 if not.
+ * @param max_depth The maximum depth @p expr should be investigated.
+ *
+ * @return return a failure reason
*/
static INLINE int can_move_to(ir_node *expr, ir_node *dest_block, int max_depth)
{
return _can_move_to(expr, dest_block, 0, max_depth);
}
+/**
+ * move a DAG given by a root node expr into a new block
+ *
+ * @param expr the root of a dag
+ * @param dest_block the destination block
+ */
static void move_to(ir_node *expr, ir_node *dest_block)
{
int i, n;
* If we reached the dominator, we are done.
* We will never put code through the dominator
*/
- if(block_dominates(expr_block, dest_block))
+ if (block_dominates(expr_block, dest_block))
return;
- for(i = 0, n = get_irn_arity(expr); i < n; ++i)
+ for (i = 0, n = get_irn_arity(expr); i < n; ++i)
move_to(get_irn_n(expr, i), dest_block);
set_nodes_block(expr, dest_block);
}
+/**
+ * return the common dominator of two blocks
+ */
static INLINE ir_node *common_idom(ir_node *b1, ir_node *b2)
{
if(block_dominates(b1, b2))
else {
ir_node *p;
- for(p = b1; !block_dominates(p, b2); p = get_Block_idom(p));
+ for (p = get_Block_idom(b1); !block_dominates(p, b2); p = get_Block_idom(p));
return p;
}
}
-
/**
* Information about a cond node.
*/
typedef struct _cond_t {
ir_node *cond; /**< The cond node. */
- struct list_head list; /**< List head which is used for queueing this cond
+ struct list_head list; /**< List head which is used for queuing this cond
into the cond bunch it belongs to. */
unsigned is_new : 1;
unsigned totally_covers : 1;
} cases[2];
} cond_t;
+/**
+ * retrieve the conditional information from a Cond node
+ */
static INLINE cond_t *get_cond(ir_node *irn, set *cond_set)
{
cond_t templ;
* blocks in which phis are located.
*/
typedef struct _cond_info_t {
- struct list_head list; /**< Used to list all of these structs per method. */
+ struct list_head list; /**< Used to list all of these structs per class. */
- struct list_head roots; /**< A list of non-depending conds. Two conds are
- independent, if yot can not reach the one from the
- other (all conds in this list have to dominate the
- block this struct is attached to. */
+ struct list_head roots; /**< A list of non-depending Conds. Two Conds are
+ independent, if it's not possible not reach one from the
+ other (all Conds in this list have to dominate the
+ block this struct is attached to). */
ir_node *first_phi; /**< The first phi node this cond info was made for. */
- set *cond_set; /**< A set of all dominating reachable conds. */
+ set *cond_set; /**< A set of all dominating reachable Conds. */
} cond_info_t;
/**
ir_node *dominator, cond_t *masked_by, int pos, int depth, cond_info_t *ci)
{
ir_node *block;
- int saw_switch_cond = 0;
+ int saw_select_cond = 0;
block = get_nodes_block(irn);
* Only check this block if it is dominated by the specified
* dominator or it has not been visited yet.
*/
- if(block_dominates(dominator, block) && get_Block_block_visited(block) < visited_nr) {
+ if (block_dominates(dominator, block) && get_Block_block_visited(block) < visited_nr) {
cond_t *res = masked_by;
int i, n;
int is_modeb_cond = get_irn_opcode(cond) == iro_Cond
&& get_irn_mode(get_Cond_selector(cond)) == mode_b;
- saw_switch_cond = !is_modeb_cond;
+ saw_select_cond = !is_modeb_cond;
/* Check, if the pred of the proj is a Cond
* with a Projb as selector.
* root list of the conf trees.
*/
else {
- DBG((dbg, LEVEL_2, "%Ddeleting from list: %n, res: %n\n", depth, masked_by->cond, res->cond));
assert(res->cases[proj].pos < 0);
list_del_init(&masked_by->list);
}
}
}
- if(get_Block_block_visited(block) < visited_nr && !saw_switch_cond) {
+ if(get_Block_block_visited(block) < visited_nr && !saw_select_cond) {
set_Block_block_visited(block, visited_nr);
* A convenience function for _find_conds.
* It sets some parameters needed for recursion to appropriate start
* values. Always use this function.
- * @param irn The node to start looking for conds from. This might
- * be the phi node we are investigating.
- * @param conds The set to record the found conds in.
+ *
+ * @param irn The node to start looking for Conds from. This might
+ * be the phi node we are investigating.
+ * @param conds The set to record the found Conds in.
*/
static INLINE void find_conds(ir_node *irn, cond_info_t *ci)
{
ir_node *block = get_nodes_block(irn);
ir_node *dom = get_Block_idom(block);
-
for(i = 0, n = get_irn_arity(block); i < n; ++i) {
ir_node *pred = get_irn_n(block, i);
static ir_node *make_mux_on_demand(ir_node *phi, ir_node *dom, cond_t *cond,
int max_depth, ir_node **mux, bitset_t *positions, int *muxes_made, long visited_nr)
{
- int i;
+ int i, can_move[2];
ir_node *projb = get_Cond_selector(cond->cond);
ir_node *bl = get_nodes_block(cond->cond);
ir_node *operands[2];
set[i] = -1;
/*
- * If this cond branch is masked by another cond, make the mux
- * for that cond first, since the mux for this cond takes
+ * If this Cond branch is masked by another cond, make the mux
+ * for that Cond first, since the Mux for this cond takes
* it as an operand.
*/
if(masked_by) {
/*
* Move the operands to the dominator block if the cond
- * made sense. Some conds found are not suitable for making a mux
+ * made sense. Some Conds found are not suitable for making a mux
* out of them, since one of their branches cannot be reached from
* the phi block. In that case we do not make a mux and return NULL.
*/
- if(operands[0] && operands[1]
- && can_move_to(operands[0], bl, max_depth)
- && can_move_to(operands[1], bl, max_depth)) {
-
- move_to(operands[0], bl);
- move_to(operands[1], bl);
-
- /* Make the mux. */
- *mux = new_r_Mux(current_ir_graph, bl, projb,
- operands[0], operands[1], get_irn_mode(operands[0]));
-
- *muxes_made += 1;
-
- DBG((dbg, LEVEL_2, "\t%n(%n, %n, %n)[%d, %d]\n",
- *mux, projb, operands[0], operands[1], set[0], set[1]));
-
- for(i = 0; i < 2; ++i)
- if(set[i] >= 0)
- bitset_set(positions, set[i]);
+ if(operands[0] && operands[1]) {
+ if (operands[0] == operands[1]) {
+ /* there is no gain in using mux in this case, as
+ it will be optimized away. We will NOT move the
+ content of the blocks either
+ */
+ for (i = 0; i < 2; ++i)
+ if(set[i] >= 0)
+ bitset_set(positions, set[i]);
+
+ *mux = operands[0];
+ return *mux;
+ }
+
+ can_move[0] = can_move_to(operands[0], bl, max_depth);
+ can_move[1] = can_move_to(operands[1], bl, max_depth);
+
+ if (can_move[0] == SUCCESS && can_move[1] == SUCCESS) {
+ move_to(operands[0], bl);
+ move_to(operands[1], bl);
+
+ /* Make the mux. */
+ *mux = new_r_Mux(current_ir_graph, bl, projb,
+ operands[0], operands[1], get_irn_mode(operands[0]));
+
+ *muxes_made += 1;
+
+ DBG((dbg, LEVEL_2, "\t%n(%n, %n, %n)[%d, %d]\n",
+ *mux, projb, operands[0], operands[1], set[0], set[1]));
+
+ for(i = 0; i < 2; ++i)
+ if(set[i] >= 0) {
+ bitset_set(positions, set[i]);
+
+ /* we have done one */
+ hook_if_conversion(current_ir_graph, phi, set[i], *mux, IF_RESULT_SUCCESS);
+ }
+ }
+ else {
+ if(can_move[0] != SUCCESS)
+ hook_if_conversion(current_ir_graph, phi, set[0], NULL, can_move[0]);
+ if(can_move[1] != SUCCESS)
+ hook_if_conversion(current_ir_graph, phi, set[1], NULL, can_move[1]);
+ }
}
+ else {
+ if(operands[0] != SUCCESS)
+ hook_if_conversion(current_ir_graph, phi, set[0], NULL, IF_RESULT_BAD_CF);
+ if(operands[1] != SUCCESS)
+ hook_if_conversion(current_ir_graph, phi, set[1], NULL, IF_RESULT_BAD_CF);
+ }
return *mux;
}
*/
list_add(&cwi->cond_info_head, &ci->list);
- DBG((dbg, LEVEL_2, "searching conds at %n(%n)\n", irn, block));
+ DBG((dbg, LEVEL_2, "searching conds at %n\n", irn));
/*
* Fill the set with conds we find on the way from
/* Init the debug stuff. */
dbg = firm_dbg_register("firm.opt.ifconv");
#if 0
- firm_dbg_set_mask(dbg, LEVEL_1 | LEVEL_2 | LEVEL_3);
+ firm_dbg_set_mask(dbg, LEVEL_1);
#endif
/* Ensure, that the dominators are computed. */
projects / libfirm / commitdiff