#include "irpass_t.h"
#include "lowering.h"
#include "error.h"
+#include "irnodeset.h"
#define foreach_out_irn(irn, i, outirn) for (i = get_irn_n_outs(irn) - 1;\
i >= 0 && (outirn = get_irn_out(irn, i)); --i)
-typedef struct walk_env {
- unsigned spare_size; /**< the allowed spare size for table switches */
- bool changed; /**< indicates whether a change was performed */
+typedef struct walk_env_t {
+ unsigned spare_size; /**< the allowed spare size for table switches */
+ bool allow_out_of_bounds;
+ bool changed; /**< indicates whether a change was performed */
+ ir_nodeset_t processed;
} walk_env_t;
-typedef struct case_data {
+typedef struct case_data_t {
long value;
ir_node *target;
} case_data_t;
-typedef struct ifcas_env {
+typedef struct cond_env_t {
ir_node *sel;
- int defindex;
+ long switch_min;
+ long switch_max;
+ ir_node *default_block;
+ unsigned num_cases;
ir_node **defusers; /**< the Projs pointing to the default case */
-} ifcas_env_t;
+} cond_env_t;
-/**
- * Evaluate a switch and decide whether we should build a table switch.
- *
- * @param cond The Cond node representing the switch.
- * @param spare_size Allowed spare size for table switches in machine words.
- * (Default in edgfe: 128)
- */
-static bool should_do_table_switch(ir_node *cond, unsigned spare_size)
+static void analyse_switch(cond_env_t *env, ir_node *cond)
{
- long default_pn;
+ long default_pn = get_Cond_default_proj(cond);
+ long switch_min = LONG_MAX;
+ long switch_max = LONG_MIN;
+ ir_node *default_block = NULL;
+ unsigned num_cases = 0;
int i;
ir_node *proj;
- long switch_min = LONG_MAX;
- long switch_max = LONG_MIN;
- unsigned long spare;
- unsigned long num_cases = 0;
-
- /* TODO: Minimum size for jump table? */
- if (get_irn_n_outs(cond) <= 4)
- return false;
-
- default_pn = get_Cond_default_proj(cond);
foreach_out_irn(cond, i, proj) {
long pn = get_Proj_proj(proj);
- if (pn == default_pn)
+ if (pn == default_pn) {
+ ir_node *target = get_irn_out(proj, 0);
+ assert(default_block == NULL || default_block == target);
+ default_block = target;
continue;
+ }
if (pn < switch_min)
switch_min = pn;
switch_max = pn;
++num_cases;
}
+ assert(default_block != NULL);
- /*
- * Here we have: num_cases and [switch_min, switch_max] interval.
- * We do an if-cascade if there are too many spare numbers.
- */
- spare = (unsigned long) switch_max - (unsigned long) switch_min - num_cases + 1;
- return spare < spare_size;
+ env->switch_min = switch_min;
+ env->switch_max = switch_max;
+ env->num_cases = num_cases;
+ env->default_block = default_block;
}
static int casecmp(const void *a, const void *b)
/**
* Creates an if cascade realizing binary search.
*/
-static void create_if_cascade(ifcas_env_t *env, dbg_info *dbgi, ir_node *block,
+static void create_if_cascade(cond_env_t *env, dbg_info *dbgi, ir_node *block,
case_data_t *curcases, unsigned numcases)
{
ir_graph *irg = get_irn_irg(block);
- ir_mode *cmp_mode;
- ir_node *cmp_sel;
- ir_node *sel_block;
+ ir_mode *cmp_mode;
+ ir_node *cmp_sel;
+ ir_node *sel_block;
/* Get the mode and sel node for the comparison. */
cmp_mode = get_irn_mode(env->sel);
if (numcases == 0) {
/* zero cases: "goto default;" */
- env->defusers[env->defindex++] = new_Jmp();
+ ARR_APP1(ir_node*, env->defusers, new_Jmp());
} else if (numcases == 1) {
/* only one case: "if (sel == val) goto target else goto default;" */
ir_node *val = new_r_Const_long(irg, cmp_mode, curcases[0].value);
ir_node *falseproj = new_r_Proj(cond, mode_X, pn_Cond_false);
set_Block_cfgpred(curcases[0].target, 0, trueproj);
- env->defusers[env->defindex++] = falseproj;
+ ARR_APP1(ir_node*, env->defusers, falseproj);
} else if (numcases == 2) {
/* only two cases: "if (sel == val[0]) goto target[0];" */
ir_node *val = new_r_Const_long(irg, cmp_mode, curcases[0].value);
trueproj = new_r_Proj(cond, mode_X, pn_Cond_true);
falseproj = new_r_Proj(cond, mode_X, pn_Cond_false);
set_Block_cfgpred(curcases[1].target, 0, trueproj);
- env->defusers[env->defindex++] = falseproj;
+ ARR_APP1(ir_node*, env->defusers, falseproj);
} else {
/* recursive case: split cases in the middle */
int midcase = numcases / 2;
}
}
+static void create_out_of_bounds_check(cond_env_t *env, ir_node *cond)
+{
+ ir_graph *irg = get_irn_irg(cond);
+ dbg_info *dbgi = get_irn_dbg_info(cond);
+ ir_node *sel = get_Cond_selector(cond);
+ ir_node *block = get_nodes_block(cond);
+ ir_mode *cmp_mode = get_irn_mode(sel);
+ ir_node **default_preds = NEW_ARR_F(ir_node*, 0);
+ unsigned long default_pn = get_Cond_default_proj(cond);
+ long delta = 0;
+ ir_node *max_const;
+ ir_node *proj_true;
+ ir_node *proj_false;
+ ir_node *cmp;
+ ir_node *proj_cmp;
+ ir_node *oob_cond;
+ ir_node *in[1];
+ ir_node *new_block;
+ int n_default_preds;
+ int i;
+ ir_node *proj;
+
+ if (mode_is_signed(cmp_mode)) {
+ cmp_mode = find_unsigned_mode(cmp_mode);
+ sel = new_r_Conv(block, sel, cmp_mode);
+ }
+
+ /* normalize so switch_min is at 0 */
+ if (env->switch_min != 0) {
+ ir_node *min_const = new_r_Const_long(irg, cmp_mode, env->switch_min);
+ sel = new_rd_Sub(dbgi, block, sel, min_const, cmp_mode);
+
+ delta = env->switch_min;
+ env->switch_min = 0;
+ env->switch_max -= delta;
+ }
+
+ /* check for out-of-bounds */
+ max_const = new_r_Const_long(irg, cmp_mode, env->switch_max);
+ cmp = new_rd_Cmp(dbgi, block, sel, max_const);
+ proj_cmp = new_r_Proj(cmp, mode_b, pn_Cmp_Le);
+ oob_cond = new_rd_Cond(dbgi, block, proj_cmp);
+ proj_true = new_r_Proj(oob_cond, mode_X, pn_Cond_true);
+ proj_false = new_r_Proj(oob_cond, mode_X, pn_Cond_false);
+
+ ARR_APP1(ir_node*, default_preds, proj_false);
+
+ /* create new block containing the cond */
+ in[0] = proj_true;
+ new_block = new_r_Block(irg, 1, in);
+ set_nodes_block(cond, new_block);
+
+ /* adapt projs */
+ foreach_out_irn(cond, i, proj) {
+ unsigned long pn = get_Proj_proj(proj);
+ unsigned long new_pn = pn - delta;
+ if (pn == default_pn) {
+ /* we might have to choose a new default_pn */
+ if (pn < (unsigned long) env->switch_max) {
+ new_pn = env->switch_max + 1;
+ set_Cond_default_proj(cond, new_pn);
+ } else {
+ new_pn = default_pn;
+ }
+ ARR_APP1(ir_node*, default_preds, proj);
+ }
+
+ set_Proj_proj(proj, new_pn);
+ set_nodes_block(proj, new_block);
+ }
+
+ /* adapt default block */
+ n_default_preds = ARR_LEN(default_preds);
+ if (n_default_preds > 1) {
+ int i;
+
+ /* create new intermediate blocks so we don't have critical edges */
+ for (i = 0; i < n_default_preds; ++i) {
+ ir_node *proj = default_preds[i];
+ ir_node *block;
+ ir_node *in[1];
+
+ in[0] = proj;
+ block = new_r_Block(irg, 1, in);
+
+ default_preds[i] = new_r_Jmp(block);
+ }
+ }
+ set_irn_in(env->default_block, n_default_preds, default_preds);
+
+ DEL_ARR_F(default_preds);
+}
+
/**
* Block-Walker: searches for Cond nodes with a non-boolean mode
*/
ir_node *condblock;
ir_node *defblock = NULL;
dbg_info *dbgi;
- ifcas_env_t ifcas_env;
+ cond_env_t cond_env;
+ unsigned long spare;
/* because we split critical blocks only blocks with 1 predecessors may
* contain Proj->Cond nodes */
if (sel_mode == mode_b)
return;
+ if (ir_nodeset_contains(&env->processed, cond))
+ return;
+ ir_nodeset_insert(&env->processed, cond);
+
/* the algorithms here don't work reliable for modes bigger than 32
* since we operate with long numbers */
assert(get_mode_size_bits(sel_mode) <= 32);
- /* ok, we have found a switch cond */
+ analyse_switch(&cond_env, cond);
- /* no need to do anything if backend handles out-of-bounds and the switch
- * is small enough */
- if (should_do_table_switch(cond, env->spare_size))
+ /*
+ * Here we have: num_cases and [switch_min, switch_max] interval.
+ * We do an if-cascade if there are too many spare numbers.
+ */
+ spare = (unsigned long) cond_env.switch_max
+ - (unsigned long) cond_env.switch_min
+ - (unsigned long) cond_env.num_cases + 1;
+ if (spare < env->spare_size) {
+ /* we won't decompose the switch. But we might have to add
+ * out-of-bounds checking */
+ if (!env->allow_out_of_bounds) {
+ create_out_of_bounds_check(&cond_env, cond);
+ env->changed = true;
+ }
return;
+ }
/*
* Switch should be transformed into an if cascade.
numcases = get_irn_n_outs(cond) - 1; /* does not contain default case */
cases = XMALLOCN(case_data_t, numcases);
- default_pn = get_Cond_default_proj(cond);
- ifcas_env.sel = sel;
- ifcas_env.defindex = 0;
- ifcas_env.defusers = XMALLOCN(ir_node*, numcases);
+ default_pn = get_Cond_default_proj(cond);
+ cond_env.sel = sel;
+ cond_env.defusers = NEW_ARR_F(ir_node*, 0);
foreach_out_irn(cond, i, proj) {
long pn = get_Proj_proj(proj);
/* Now create the if cascade */
condblock = get_nodes_block(cond);
dbgi = get_irn_dbg_info(cond);
- create_if_cascade(&ifcas_env, dbgi, condblock, cases, numcases);
+ create_if_cascade(&cond_env, dbgi, condblock, cases, numcases);
/* Connect new default case users */
- set_irn_in(defblock, ifcas_env.defindex, ifcas_env.defusers);
+ set_irn_in(defblock, ARR_LEN(cond_env.defusers), cond_env.defusers);
xfree(cases);
- xfree(ifcas_env.defusers);
+ DEL_ARR_F(cond_env.defusers);
}
-void lower_switch(ir_graph *irg, unsigned spare_size)
+void lower_switch(ir_graph *irg, unsigned spare_size, int allow_out_of_bounds)
{
walk_env_t env;
env.changed = false;
env.spare_size = spare_size;
+ env.allow_out_of_bounds = allow_out_of_bounds;
+ ir_nodeset_init(&env.processed);
remove_critical_cf_edges(irg);
assure_irg_outs(irg);
irg_block_walk_graph(irg, find_cond_nodes, NULL, &env);
+ ir_nodeset_destroy(&env.processed);
if (env.changed) {
/* control flow changed */
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