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Commit bc785b94 authored by Matthias Braun's avatar Matthias Braun
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cfopt: code cleanup

parent 550ae1cf
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ir/opt/cfopt.c
View file @ bc785b94
......@@ -74,13 +74,13 @@ static void set_Block_removable(ir_node *block, bool removable)
}
/** check if a block has the removable property set. */
static bool is_Block_removable(ir_node *block)
static bool is_Block_removable(const ir_node *block)
{
return get_Block_mark(block);
}
/** checks if a given Cond node is a switch Cond. */
static bool is_switch_Cond(ir_node *cond)
static bool is_switch_Cond(const ir_node *cond)
{
ir_node *sel = get_Cond_selector(cond);
return get_irn_mode(sel) != mode_b;
......@@ -91,8 +91,12 @@ static void clear_link_and_mark_blocks_removable(ir_node *node, void *ctx)
{
(void) ctx;
set_irn_link(node, NULL);
if (is_Block(node))
if (is_Block(node)) {
set_Block_removable(node, true);
set_Block_phis(node, NULL);
} else if (is_Phi(node)) {
set_Phi_next(node, NULL);
}
}
/**
......@@ -109,8 +113,7 @@ static void collect_nodes(ir_node *n, void *ctx)
if (is_Phi(n)) {
/* Collect Phi nodes to compact ins along with block's ins. */
ir_node *block = get_nodes_block(n);
set_irn_link(n, get_irn_link(block));
set_irn_link(block, n);
add_Block_phi(block, n);
} else if (is_Block(n)) {
if (has_Block_entity(n)) {
/* block with a jump label attached cannot be removed. */
......@@ -122,8 +125,6 @@ static void collect_nodes(ir_node *n, void *ctx)
} else {
/* Check for non-empty block. */
ir_node *block = get_nodes_block(n);
if (is_Bad(block))
return;
set_Block_removable(block, false);
......@@ -140,7 +141,7 @@ static void collect_nodes(ir_node *n, void *ctx)
}
/** Returns true if pred is predecessor of block b. */
static bool is_pred_of(ir_node *pred, ir_node *b)
static bool is_pred_of(const ir_node *pred, const ir_node *b)
{
int i;
......@@ -179,7 +180,7 @@ static bool is_pred_of(ir_node *pred, ir_node *b)
* To perform the test for pos, we must regard predecessors before pos
* as already removed.
**/
static unsigned test_whether_dispensable(ir_node *b, int pos)
static unsigned test_whether_dispensable(const ir_node *b, int pos)
{
ir_node *pred = get_Block_cfgpred(b, pos);
ir_node *predb = get_nodes_block(pred);
......@@ -194,7 +195,7 @@ static unsigned test_whether_dispensable(ir_node *b, int pos)
goto non_dispensable;
/* Seems to be empty. At least we detected this in collect_nodes. */
if (get_irn_link(b) != NULL) {
if (get_Block_phis(b) != NULL) {
int n_cfgpreds = get_Block_n_cfgpreds(b);
int i;
/* there are Phi nodes */
......@@ -287,7 +288,8 @@ non_dispensable:
static void optimize_blocks(ir_node *b, void *ctx)
{
int i, j, k, n, max_preds, n_preds, p_preds = -1;
ir_node *pred, *phi, *next;
ir_node *phi;
ir_node *next;
ir_node **in;
merge_env *env = (merge_env*)ctx;
......@@ -305,21 +307,27 @@ static void optimize_blocks(ir_node *b, void *ctx)
in = XMALLOCN(ir_node*, max_preds);
/*- Fix the Phi nodes of the current block -*/
for (phi = (ir_node*)get_irn_link(b); phi != NULL; phi = (ir_node*)next) {
assert(is_Phi(phi));
next = (ir_node*)get_irn_link(phi);
for (phi = get_Block_phis(b); phi != NULL; phi = next) {
next = get_Phi_next(phi);
/* Find the new predecessors for the Phi */
p_preds = 0;
for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) {
ir_graph *irg = get_irn_irg(b);
pred = get_Block_cfgpred_block(b, i);
ir_node *predx = get_Block_cfgpred(b, i);
ir_node *pred;
if (is_Bad(pred)) {
/* case Phi 1: maintain Bads, as somebody else is responsible to remove them */
/* case Phi 1: maintain Bads, as somebody else is responsible to
* remove them */
if (is_Bad(predx)) {
in[p_preds++] = new_r_Bad(irg, get_irn_mode(phi));
} else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
/* case Phi 2: It's an empty block and not yet visited. */
continue;
}
pred = get_nodes_block(predx);
/* case Phi 2: It's an empty block and not yet visited. */
if (is_Block_removable(pred) && !Block_block_visited(pred)) {
ir_node *phi_pred = get_Phi_pred(phi, i);
for (j = 0, k = get_Block_n_cfgpreds(pred); j < k; j++) {
......@@ -348,10 +356,11 @@ static void optimize_blocks(ir_node *b, void *ctx)
assert(p_preds == max_preds);
/* Fix the node */
if (p_preds == 1)
if (p_preds == 1) {
exchange(phi, in[0]);
else
} else {
set_irn_in(phi, p_preds, in);
}
env->changed = true;
}
......@@ -368,37 +377,43 @@ static void optimize_blocks(ir_node *b, void *ctx)
ir_node *next_phi;
/* we found a predecessor block at position k that will be removed */
for (phi = (ir_node*)get_irn_link(predb); phi; phi = next_phi) {
for (phi = get_Block_phis(predb); phi != NULL; phi = next_phi) {
int q_preds = 0;
next_phi = (ir_node*)get_irn_link(phi);
assert(is_Phi(phi));
next_phi = get_Phi_next(phi);
if (get_Block_idom(b) != predb) {
/* predb is not the dominator. There can't be uses of pred's Phi nodes, kill them .*/
/* predb is not the dominator. There can't be uses of
* pred's Phi nodes, kill them .*/
ir_graph *irg = get_irn_irg(b);
ir_mode *mode = get_irn_mode(phi);
exchange(phi, new_r_Bad(irg, mode));
} else {
/* predb is the direct dominator of b. There might be uses of the Phi nodes from
predb in further block, so move this phi from the predecessor into the block b */
/* predb is the direct dominator of b. There might be uses
* of the Phi nodes from predb in further block, so move
* this phi from the predecessor into the block b */
set_nodes_block(phi, b);
set_irn_link(phi, get_irn_link(b));
set_irn_link(b, phi);
set_Phi_next(phi, get_Block_phis(b));
set_Block_phis(b, phi);
env->phis_moved = true;
/* first, copy all 0..k-1 predecessors */
for (i = 0; i < k; i++) {
pred = get_Block_cfgpred_block(b, i);
ir_node *predx = get_Block_cfgpred(b, i);
ir_node *pred_block;
if (is_Bad(pred)) {
if (is_Bad(predx)) {
ir_graph *irg = get_irn_irg(b);
ir_mode *mode = get_irn_mode(phi);
in[q_preds++] = new_r_Bad(irg, mode);
} else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
continue;
}
pred_block = get_nodes_block(predx);
if (is_Block_removable(pred_block)
&& !Block_block_visited(pred_block)) {
int n_cfgpreds = get_Block_n_cfgpreds(pred_block);
/* It's an empty block and not yet visited. */
for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
if (! is_Bad(get_Block_cfgpred(pred, j))) {
for (j = 0; j < n_cfgpreds; j++) {
if (!is_Bad(get_Block_cfgpred(pred_block, j))) {
in[q_preds++] = phi;
} else {
ir_graph *irg = get_irn_irg(b);
......@@ -493,7 +508,7 @@ static void optimize_blocks(ir_node *b, void *ctx)
env->changed = true;
/* see if phi-fix was correct */
assert(get_irn_link(b) == NULL || p_preds == -1 || (n_preds == p_preds));
assert(get_Block_phis(b) == NULL || p_preds == -1 || (n_preds == p_preds));
xfree(in);
}
......@@ -697,8 +712,7 @@ typedef struct skip_env {
/**
* Post-Block-walker: Optimize useless if's (boolean Cond nodes
* with same true/false target)
* away.
* with same true/false target) away.
*/
static void optimize_ifs(ir_node *block, void *x)
{
......@@ -746,7 +760,8 @@ static void remove_empty_blocks(ir_node *block, void *x)
if (Block_block_visited(jmp_block)) {
continue;
/* otherwise we could break the walker,
* if block was reached via KeepAlive edge -> jmp_block -> A ---> block,
* if block was reached via
* KeepAlive edge -> jmp_block -> A ---> block,
* because the walker cannot handle Id nodes.
*
* A B
......@@ -782,7 +797,8 @@ static void remove_empty_blocks(ir_node *block, void *x)
exchange(jmp_block, pred_block);
env->changed = true;
} else if (! has_phis(env->phase, block)) {
/* all predecessors can skip the jmp block, so block gets some new predecessors
/* all predecessors can skip the jmp block, so block gets some new
* predecessors
*
* A B A B
* \ / | |
......@@ -790,10 +806,10 @@ static void remove_empty_blocks(ir_node *block, void *x)
* \ / \ | | /
* block block
*/
ir_node **ins = NULL;
ir_node **ins = ALLOCAN(ir_node*, n_preds+n_jpreds);
int j;
NEW_ARR_A(ir_node *, ins, n_preds+n_jpreds);
/* first copy the old predecessors, because the outer loop (i) still walks over them */
/* first copy the old predecessors, because the outer loop (i)
* still walks over them */
for (j = 0; j < n_preds; ++j) {
ins[j] = get_Block_cfgpred(block, j);
}
......@@ -875,7 +891,8 @@ static ir_graph_state_t do_cfopt(ir_graph *irg)
cfgopt_ignoring_phis(irg);
/* we use the mark flag to mark removable blocks */
ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_LINK);
ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_LINK
| IR_RESOURCE_PHI_LIST);
/* The switch Cond optimization might expose unreachable code, so we loop */
for (;;) {
......@@ -929,7 +946,8 @@ static ir_graph_state_t do_cfopt(ir_graph *irg)
}
remove_End_Bads_and_doublets(end);
ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_LINK);
ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_LINK
| IR_RESOURCE_PHI_LIST);
if (env.phis_moved) {
/* Bad: when we moved Phi's, we might produce dead Phi nodes
......@@ -976,7 +994,8 @@ static optdesc_t opt_cf = {
do_cfopt,
};
void optimize_cf(ir_graph *irg) {
void optimize_cf(ir_graph *irg)
{
perform_irg_optimization(irg, &opt_cf);
}
......
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