static ir_node *equivalent_node_Mux(ir_node *n)
{
ir_node *oldn = n, *sel = get_Mux_sel(n);
+ ir_node *n_t, *n_f;
tarval *ts = value_of(sel);
/* Mux(true, f, t) == t */
if (ts == tarval_b_true) {
n = get_Mux_true(n);
DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_C);
+ return n;
}
/* Mux(false, f, t) == f */
- else if (ts == tarval_b_false) {
+ if (ts == tarval_b_false) {
n = get_Mux_false(n);
DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_C);
+ return n;
+ }
+ n_t = get_Mux_true(n);
+ n_f = get_Mux_false(n);
+
+ /* Mux(v, x, T) == x */
+ if (is_Unknown(n_f)) {
+ n = n_t;
+ DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
+ return n;
}
+ /* Mux(v, T, x) == x */
+ if (is_Unknown(n_t)) {
+ n = n_f;
+ DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
+ return n;
+ }
+
/* Mux(v, x, x) == x */
- else if (get_Mux_false(n) == get_Mux_true(n)) {
- n = get_Mux_true(n);
+ if (n_t == n_f) {
+ n = n_t;
DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
+ return n;
}
- else if (is_Proj(sel) && !mode_honor_signed_zeros(get_irn_mode(n))) {
+ if (is_Proj(sel) && !mode_honor_signed_zeros(get_irn_mode(n))) {
ir_node *cmp = get_Proj_pred(sel);
long proj_nr = get_Proj_proj(sel);
ir_node *f = get_Mux_false(n);
ir_node *f = get_Mux_false(n);
ir_graph *irg = current_ir_graph;
+ if (is_Mux(t)) {
+ ir_node* block = get_nodes_block(n);
+ ir_node* c0 = sel;
+ ir_node* c1 = get_Mux_sel(t);
+ ir_node* t1 = get_Mux_true(t);
+ ir_node* f1 = get_Mux_false(t);
+ if (f == f1) {
+ /* Mux(c0, Mux(c1, x, y), y) -> typical if (c0 && c1) x else y */
+ ir_node* and_ = new_r_And(irg, block, c0, c1, mode_b);
+ ir_node* new_mux = new_r_Mux(irg, block, and_, f1, t1, mode);
+ n = new_mux;
+ sel = and_;
+ f = f1;
+ t = t1;
+ DBG_OPT_ALGSIM0(oldn, t, FS_OPT_MUX_COMBINE);
+ } else if (f == t1) {
+ /* Mux(c0, Mux(c1, x, y), x) */
+ ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
+ ir_node* and_ = new_r_And(irg, block, c0, not_c1, mode_b);
+ ir_node* new_mux = new_r_Mux(irg, block, and_, t1, f1, mode);
+ n = new_mux;
+ sel = and_;
+ f = t1;
+ t = f1;
+ DBG_OPT_ALGSIM0(oldn, t, FS_OPT_MUX_COMBINE);
+ }
+ } else if (is_Mux(f)) {
+ ir_node* block = get_nodes_block(n);
+ ir_node* c0 = sel;
+ ir_node* c1 = get_Mux_sel(f);
+ ir_node* t1 = get_Mux_true(f);
+ ir_node* f1 = get_Mux_false(f);
+ if (t == t1) {
+ /* Mux(c0, x, Mux(c1, x, y)) -> typical if (c0 || c1) x else y */
+ ir_node* or_ = new_r_Or(irg, block, c0, c1, mode_b);
+ ir_node* new_mux = new_r_Mux(irg, block, or_, f1, t1, mode);
+ n = new_mux;
+ sel = or_;
+ f = f1;
+ t = t1;
+ DBG_OPT_ALGSIM0(oldn, f, FS_OPT_MUX_COMBINE);
+ } else if (t == f1) {
+ /* Mux(c0, x, Mux(c1, y, x)) */
+ ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
+ ir_node* or_ = new_r_Or(irg, block, c0, not_c1, mode_b);
+ ir_node* new_mux = new_r_Mux(irg, block, or_, t1, f1, mode);
+ n = new_mux;
+ sel = or_;
+ f = t1;
+ t = f1;
+ DBG_OPT_ALGSIM0(oldn, f, FS_OPT_MUX_COMBINE);
+ }
+ }
+
/* first normalization step: move a possible zero to the false case */
if (is_Proj(sel)) {
ir_node *cmp = get_Proj_pred(sel);
tarval *null = get_tarval_null(mode);
tarval *diff, *min;
+ if (get_opt_allow_conv_b()) {
+ if (tarval_is_one(a) && tarval_is_null(b)) {
+ ir_node *block = get_nodes_block(n);
+ ir_node *conv = new_r_Conv(current_ir_graph, block, sel, mode);
+ n = conv;
+ DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_CONV);
+ return n;
+ } else if (tarval_is_null(a) && tarval_is_one(b)) {
+ ir_node *block = get_nodes_block(n);
+ ir_node *not_ = new_r_Not(current_ir_graph, block, sel, mode_b);
+ ir_node *conv = new_r_Conv(current_ir_graph, block, not_, mode);
+ n = conv;
+ DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_CONV);
+ return n;
+ }
+ }
+ /* TODO: it's not really clear if that helps in general or should be moved
+ * to backend, especially with the MUX->Conv transformation above */
if (tarval_cmp(a, b) & pn_Cmp_Gt) {
diff = tarval_sub(a, b, NULL);
min = b;
min = a;
}
- if (diff == get_tarval_one(mode) && min != null) {
+ if (diff == get_tarval_one(mode)) {
dbg_info *dbg = get_irn_dbg_info(n);
ir_node *block = get_nodes_block(n);
- ir_graph *irg = current_ir_graph;
ir_node *t = new_Const(tarval_sub(a, min, NULL));
ir_node *f = new_Const(tarval_sub(b, min, NULL));
n = new_rd_Mux(dbg, irg, block, sel, f, t, mode);
#include "irnode_t.h"
#include "cdep.h"
#include "ircons.h"
-#include "irdom.h"
#include "irgmod.h"
#include "irgopt.h"
#include "irgwalk.h"
#include "irdump.h"
#include "debug.h"
+/**
+ * Environment for if-conversion.
+ */
+typedef struct walker_env {
+ const ir_settings_if_conv_t *params; /**< Conversion parameter. */
+ int changed; /**< Set if the graph was changed. */
+} walker_env;
+
DEBUG_ONLY(static firm_dbg_module_t *dbg);
-/** allow every Mux to be created. */
+/**
+ * Default callback for Mux creation: allows every Mux to be created.
+ */
static int default_allow_ifconv(ir_node *sel, ir_node* phi_list, int i, int j)
{
(void) sel;
/**
* Returns non-zero if a Block can be emptied.
+ *
+ * @param block the block
*/
static int can_empty_block(ir_node *block) {
return get_Block_mark(block) == 0;
}
-
+/**
+ * Find the ProjX node leading from block dependency to block start.
+ *
+ * @param start a block that is control depended on dependency
+ * @param dependency the block that decides whether start is executed
+ *
+ * @return a ProjX node that represent the decision control flow or
+ * NULL is start is not dependent at all or a block on the way
+ * cannot be emptied
+ */
static ir_node* walk_to_projx(ir_node* start, const ir_node* dependency)
{
int arity;
arity = get_irn_arity(start);
for (i = 0; i < arity; ++i) {
ir_node* pred = get_irn_n(start, i);
- ir_node* pred_block = get_nodes_block(pred);
+ ir_node* pred_block = get_nodes_block(skip_Proj(pred));
if (pred_block == dependency) {
if (is_Proj(pred)) {
assert(get_irn_mode(pred) == mode_X);
+ /* we found it */
return pred;
}
+ /* Not a Proj? Should not happen. */
return NULL;
}
if (is_Proj(pred)) {
assert(get_irn_mode(pred) == mode_X);
+ /* another Proj but not from the control block */
return NULL;
}
/**
- * Copies the DAG starting at node to the ith predecessor block of src_block
- * -if the node isn't in the src_block, this is a nop and the node is returned
- * -if the node is a phi in the src_block, the ith predecessor of the phi is
- * returned
- * otherwise returns the copy of the passed node
+ * Recursively copies the DAG starting at node to the i-th predecessor
+ * block of src_block
+ * - if node isn't in the src_block, recursion ends and node is returned
+ * - if node is a Phi in the src_block, the i-th predecessor of this Phi is
+ * returned and recursion ends
+ * otherwise returns a copy of the passed node created in the i-th predecessor of
+ * src_block.
+ *
+ * @param node a root of a DAG
+ * @param src_block the block of the DAG
+ * @param i the position of the predecessor the DAG
+ * is moved to
+ *
+ * @return the root of the copied DAG
*/
static ir_node* copy_to(ir_node* node, ir_node* src_block, int i)
{
ir_node* dst_block;
ir_node* copy;
- int arity;
int j;
- if (get_nodes_block(node) != src_block) return node;
- if (get_irn_op(node) == op_Phi) return get_irn_n(node, i);
+ if (get_nodes_block(node) != src_block) {
+ /* already outside src_block, do not copy */
+ return node;
+ }
+ if (is_Phi(node)) {
+ /* move through the Phi to the i-th predecessor */
+ return get_irn_n(node, i);
+ }
+ /* else really need a copy */
copy = exact_copy(node);
dst_block = get_nodes_block(get_irn_n(src_block, i));
set_nodes_block(copy, dst_block);
DB((dbg, LEVEL_1, "Copying node %+F to block %+F, copy is %+F\n",
node, dst_block, copy));
- arity = get_irn_arity(node);
- for (j = 0; j < arity; ++j) {
+ /* move recursively all predecessors */
+ for (j = get_irn_arity(node) - 1; j >= 0; --j) {
set_irn_n(copy, j, copy_to(get_irn_n(node, j), src_block, i));
DB((dbg, LEVEL_2, "-- pred %d is %+F\n", j, get_irn_n(copy, j)));
}
/**
- * Remove predecessors i and j from node and add predecessor new_pred
+ * Remove predecessors i and j (i < j) from a node and
+ * add an additional predecessor new_pred.
+ *
+ * @param node the node whose inputs are changed
+ * @param i the first index to remove
+ * @param j the second index to remove
+ * @param new_pred a node that is added as a new input to node
*/
static void rewire(ir_node* node, int i, int j, ir_node* new_pred)
{
/**
- * Remove the jth predecessors from the ith predecessor of block and add it to block
+ * Remove the j-th predecessors from the i-th predecessor of block and add it to block
*/
static void split_block(ir_node* block, int i, int j)
{
}
}
-
-static void if_conv_walker(ir_node* block, void* env)
+/**
+ * Block walker: Search for diamonds and do the if conversion.
+ */
+static void if_conv_walker(ir_node *block, void *ctx)
{
- ir_settings_if_conv_t* opt_info = env;
+ walker_env *env = ctx;
int arity;
int i;
if (projx1 == NULL) continue;
phi = get_Block_phis(block);
- if (!opt_info->allow_ifconv(get_Cond_selector(cond), phi, i, j)) continue;
+ if (!env->params->allow_ifconv(get_Cond_selector(cond), phi, i, j))
+ continue;
DB((dbg, LEVEL_1, "Found Cond %+F with proj %+F and %+F\n",
cond, projx0, projx1
));
+ env->changed = 1;
prepare_path(block, i, dependency);
prepare_path(block, j, dependency);
arity = get_irn_arity(block);
} else {
rewire(phi, i, j, mux);
}
-
phi = next_phi;
} while (phi != NULL);
}
/**
- * Block walker: clear block mark and Phi list
+ * Block walker: clear block marks and Phi lists.
*/
static void init_block_link(ir_node *block, void *env)
{
/**
- * Daisy-chain all phis in a block
+ * Daisy-chain all Phis in a block.
* If a non-movable node is encountered set the has_pinned flag in its block.
*/
static void collect_phis(ir_node *node, void *env) {
} else {
if (is_no_Block(node) && get_irn_pinned(node) == op_pin_state_pinned) {
/*
- * Ignore control flow nodes, these will be removed.
- * This ignores Raise. That is surely bad. FIXME.
+ * Ignore control flow nodes (except Raise), these will be removed.
*/
- if (!is_cfop(node)) {
+ if (!is_cfop(node) && !is_Raise(node)) {
ir_node *block = get_nodes_block(node);
DB((dbg, LEVEL_2, "Node %+F in block %+F is unmovable\n", node, block));
}
}
-static void optimise_muxs_0(ir_node* mux, void* env)
-{
- ir_node* t;
- ir_node* f;
-
- (void) env;
-
- if (!is_Mux(mux)) return;
-
- t = get_Mux_true(mux);
- f = get_Mux_false(mux);
-
- DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", mux, t, f));
-
- if (is_Unknown(t)) {
- DB((dbg, LEVEL_3, "Replace Mux with unknown operand by %+F\n", f));
- exchange(mux, f);
- return;
- }
- if (is_Unknown(f)) {
- DB((dbg, LEVEL_3, "Replace Mux with unknown operand by %+F\n", t));
- exchange(mux, t);
- return;
- }
-
- if (is_Mux(t)) {
- ir_graph* irg = current_ir_graph;
- ir_node* block = get_nodes_block(mux);
- ir_mode* mode = get_irn_mode(mux);
- ir_node* c0 = get_Mux_sel(mux);
- ir_node* c1 = get_Mux_sel(t);
- ir_node* t1 = get_Mux_true(t);
- ir_node* f1 = get_Mux_false(t);
- if (f == f1) {
- /* Mux(c0, Mux(c1, x, y), y) -> typical if (c0 && c1) x else y */
- ir_node* and_ = new_r_And(irg, block, c0, c1, mode_b);
- ir_node* new_mux = new_r_Mux(irg, block, and_, f1, t1, mode);
- exchange(mux, new_mux);
- } else if (f == t1) {
- /* Mux(c0, Mux(c1, x, y), x) */
- ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
- ir_node* and_ = new_r_And(irg, block, c0, not_c1, mode_b);
- ir_node* new_mux = new_r_Mux(irg, block, and_, t1, f1, mode);
- exchange(mux, new_mux);
- }
- } else if (is_Mux(f)) {
- ir_graph* irg = current_ir_graph;
- ir_node* block = get_nodes_block(mux);
- ir_mode* mode = get_irn_mode(mux);
- ir_node* c0 = get_Mux_sel(mux);
- ir_node* c1 = get_Mux_sel(f);
- ir_node* t1 = get_Mux_true(f);
- ir_node* f1 = get_Mux_false(f);
- if (t == t1) {
- /* Mux(c0, x, Mux(c1, x, y)) -> typical if (c0 || c1) x else y */
- ir_node* or_ = new_r_Or(irg, block, c0, c1, mode_b);
- ir_node* new_mux = new_r_Mux(irg, block, or_, f1, t1, mode);
- exchange(mux, new_mux);
- } else if (t == f1) {
- /* Mux(c0, x, Mux(c1, y, x)) */
- ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
- ir_node* or_ = new_r_Or(irg, block, c0, not_c1, mode_b);
- ir_node* new_mux = new_r_Mux(irg, block, or_, t1, f1, mode);
- exchange(mux, new_mux);
- }
- }
-}
-
-
-static void optimise_muxs_1(ir_node* mux, void* env)
-{
- ir_node* t;
- ir_node* f;
- ir_mode* mode;
-
- (void) env;
-
- if (!is_Mux(mux)) return;
-
- t = get_Mux_true(mux);
- f = get_Mux_false(mux);
-
- DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", mux, t, f));
-
- mode = get_irn_mode(mux);
-
- if (is_Const(t) && is_Const(f) && (mode_is_int(mode))) {
- ir_node* block = get_nodes_block(mux);
- ir_node* c = get_Mux_sel(mux);
- tarval* tv_t = get_Const_tarval(t);
- tarval* tv_f = get_Const_tarval(f);
- if (tarval_is_one(tv_t) && tarval_is_null(tv_f)) {
- ir_node* conv = new_r_Conv(current_ir_graph, block, c, mode);
- exchange(mux, conv);
- } else if (tarval_is_null(tv_t) && tarval_is_one(tv_f)) {
- ir_node* not_ = new_r_Not(current_ir_graph, block, c, mode_b);
- ir_node* conv = new_r_Conv(current_ir_graph, block, not_, mode);
- exchange(mux, conv);
- }
- }
-}
-
-
void opt_if_conv(ir_graph *irg, const ir_settings_if_conv_t *params)
{
- ir_settings_if_conv_t p;
+ walker_env env;
/* get the parameters */
- p = (params != NULL ? *params : default_info);
+ env.params = (params != NULL ? params : &default_info);
+ env.changed = 0;
FIRM_DBG_REGISTER(dbg, "firm.opt.ifconv");
remove_critical_cf_edges(irg);
compute_cdep(irg);
- assure_doms(irg);
ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
irg_block_walk_graph(irg, init_block_link, NULL, NULL);
irg_walk_graph(irg, collect_phis, NULL, NULL);
- irg_block_walk_graph(irg, NULL, if_conv_walker, &p);
+ irg_block_walk_graph(irg, NULL, if_conv_walker, &env);
ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
- local_optimize_graph(irg);
-
- irg_walk_graph(irg, NULL, optimise_muxs_0, NULL);
-#if 1
- irg_walk_graph(irg, NULL, optimise_muxs_1, NULL);
-#endif
+ if (env.changed) {
+ local_optimize_graph(irg);
- /* TODO: graph might be changed, handle more graceful */
- set_irg_outs_inconsistent(irg);
- set_irg_extblk_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
- free_dom(irg);
+ /* graph has changed, invalidate analysis info */
+ set_irg_outs_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+ set_irg_loopinfo_inconsistent(irg);
+ set_irg_doms_inconsistent(irg);
+ }
free_cdep(irg);
}
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