#include "bechordal_t.h"
#include "bejavacoal.h"
+// only rematerialise when costs are less than REMAT_COST_LIMIT
+#define REMAT_COST_LIMIT 4
+
/* This enables re-computation of values. Current state: Unfinished and buggy. */
#undef BUGGY_REMAT
free(env);
}
+/**
+ * ____ _ ____ _ _
+ * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
+ * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
+ * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
+ * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
+ *
+ */
+
+void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
+ spill_info_t *info;
+ reloader_t *rel;
+
+ assert(sched_is_scheduled(before));
+ assert(arch_irn_consider_in_reg_alloc(env->chordal_env->birg->main_env->arch_env, env->cls, to_spill));
+
+ info = get_spillinfo(env, to_spill);
+
+ if(is_Phi(to_spill)) {
+ int i, arity;
+ // create spillinfos for the phi arguments
+ for(i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
+ ir_node *arg = get_irn_n(to_spill, i);
+ get_spillinfo(env, arg);
+ }
+ }
+
+ rel = obstack_alloc(&env->obst, sizeof(rel[0]));
+ rel->reloader = before;
+ rel->next = info->reloaders;
+ info->reloaders = rel;
+ be_liveness_add_missing(env->chordal_env->lv);
+}
+
+void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
+ ir_node *predblock, *last;
+
+ /* simply add the reload to the beginning of the block if we only have 1 predecessor
+ * (we don't need to check for phis as there can't be any in a block with only 1 pred)
+ */
+ if(get_Block_n_cfgpreds(block) == 1) {
+ assert(!is_Phi(sched_first(block)));
+ be_add_reload(env, to_spill, sched_first(block));
+ return;
+ }
+
+ /* We have to reload the value in pred-block */
+ predblock = get_Block_cfgpred_block(block, pos);
+ last = sched_last(predblock);
+
+ /* we might have projs and keepanys behind the jump... */
+ while(is_Proj(last) || be_is_Keep(last)) {
+ last = sched_prev(last);
+ assert(!sched_is_end(last));
+ }
+ assert(is_cfop(last));
+
+ // add the reload before the (cond-)jump
+ be_add_reload(env, to_spill, last);
+}
+
+void be_spill_phi(spill_env_t *env, ir_node *node) {
+ int i, arity;
+
+ assert(is_Phi(node));
+
+ pset_insert_ptr(env->mem_phis, node);
+
+ // create spillinfos for the phi arguments
+ get_spillinfo(env, node);
+ for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
+ ir_node *arg = get_irn_n(node, i);
+ get_spillinfo(env, arg);
+ }
+}
+
+/*
+ * ____ _ ____ _ _ _
+ * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
+ * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
+ * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
+ * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
+ * |_|
+ */
+
/**
* Schedules a node after an instruction. (That is the place after all projs and phis
* that are scheduled after the instruction)
+ * This function also skips phi nodes at the beginning of a block
*/
static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
ir_node *next = sched_next(sched_after);
- while(!sched_is_end(next)) {
- if(!is_Proj(next) && !is_Phi(next))
- break;
+ while(is_Proj(next) || is_Phi(next)) {
next = sched_next(next);
}
+ assert(next != NULL);
if(sched_is_end(next)) {
- next = sched_last(get_nodes_block(sched_after));
- sched_add_after(next, node);
+ sched_add_after(sched_last(get_nodes_block(sched_after)), node);
} else {
sched_add_before(next, node);
}
/* Trying to spill an already spilled value, no need for a new spill
* node then, we can simply connect to the same one for this reload
+ *
+ * (although rematerialisation code should handle most of these cases
+ * this can still happen when spilling Phis)
*/
if(be_is_Reload(to_spill)) {
spillinfo->spill = get_irn_n(to_spill, be_pos_Reload_mem);
}
}
-static INLINE ir_node *skip_projs(ir_node *node) {
- while(is_Proj(node)) {
- node = sched_next(node);
- assert(!sched_is_end(node));
- }
-
- return node;
-}
+/*
+ *
+ * ____ _ _ _ _
+ * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
+ * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
+ * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
+ * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
+ *
+ */
-#if 0
/**
- * Searchs the schedule backwards until we reach the first use or def of a
- * value or a phi.
- * Returns the node after this node (so that you can do sched_add_before)
+ * Tests whether value @p arg is available before node @p reloader
+ * @returns 1 if value is available, 0 otherwise
*/
-static ir_node *find_last_use_def(spill_env_t *env, ir_node *block, ir_node *value) {
- ir_node *node, *last;
+static int is_value_available(spill_env_t *env, ir_node *arg, ir_node *reloader) {
+ if(is_Unknown(arg) || arg == new_NoMem())
+ return 1;
- last = NULL;
- sched_foreach_reverse(block, node) {
- int i, arity;
+ if(be_is_Spill(arg))
+ return 1;
- if(is_Phi(node)) {
- return last;
- }
- if(value == node) {
- return skip_projs(last);
- }
- for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
- ir_node *arg = get_irn_n(node, i);
- if(arg == value) {
- return skip_projs(last);
- }
- }
- last = node;
+ if(arg == get_irg_frame(env->chordal_env->irg))
+ return 1;
+
+#if 0
+ /* we want to remat before the insn reloader
+ * thus an arguments is alive if
+ * - it interferes with the reloaders result
+ * or
+ * - or it is (last-) used by reloader itself
+ */
+ int i, m;
+
+ if (values_interfere(reloader, arg))
+ return 1;
+
+ for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
+ ir_node *rel_arg = get_irn_n(reloader, i);
+ if (rel_arg == arg)
+ return 1;
}
- // simply return first node if no def or use found
- return sched_first(block);
-}
+ /* arg is not alive before reloader */
+ return 0;
#endif
-#ifdef BUGGY_REMAT
+ return 0;
+}
/**
- * Check if a spilled node could be rematerialized.
- *
- * @param senv the spill environment
- * @param spill the Spill node
- * @param spilled the node that was spilled
- * @param reloader a irn that requires a reload
+ * Checks whether the node can principally be rematerialized
*/
-static int check_remat_conditions(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
- int pos, max;
+static int is_remat_node(spill_env_t *env, ir_node *node) {
+ const arch_env_t *arch_env = env->chordal_env->birg->main_env->arch_env;
- /* check for 'normal' spill and general remat condition */
- if (!arch_irn_is(senv->chordal_env->birg->main_env->arch_env, spilled, rematerializable))
- return 0;
+ assert(!be_is_Spill(node));
- /* check availability of original arguments */
- if (is_Block(reloader)) {
+ if(be_is_Reload(node))
+ return 1;
- /* we want to remat at the end of a block.
- * thus all arguments must be alive at the end of the block
- */
- for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
- ir_node *arg = get_irn_n(spilled, pos);
- if (!is_live_end(reloader, arg))
- return 0;
- }
+ // TODO why does arch_irn_is say rematerializable anyway?
+ if(be_is_Barrier(node))
+ return 0;
- } else {
+ if(arch_irn_is(arch_env, node, rematerializable))
+ return 1;
- /* we want to remat before the insn reloader
- * thus an arguments is alive if
- * - it interferes with the reloaders result
- * or
- * - or it is (last-) used by reloader itself
- */
- for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
- ir_node *arg = get_irn_n(spilled, pos);
- int i, m;
-
- if (values_interfere(reloader, arg))
- goto is_alive;
-
- for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
- ir_node *rel_arg = get_irn_n(reloader, i);
- if (rel_arg == arg)
- goto is_alive;
- }
+ if(be_is_StackParam(node))
+ return 1;
- /* arg is not alive before reloader */
- return 0;
+ return 0;
+}
+
+/**
+ * Check if a node is rematerializable. This tests for the following conditions:
+ *
+ * - The node itself is rematerializable
+ * - All arguments of the node are available or also rematerialisable
+ * - The costs for the rematerialisation operation is less or equal a limit
+ *
+ * Returns the costs needed for rematerialisation or something
+ * > REMAT_COST_LIMIT if remat is not possible.
+ */
+static int check_remat_conditions_costs(spill_env_t *env, ir_node *spilled, ir_node *reloader, int parentcosts) {
+ int i, arity;
+ int argremats;
+ int costs = 0;
-is_alive: ;
+ if(!is_remat_node(env, spilled))
+ return REMAT_COST_LIMIT;
+ if(be_is_Reload(spilled)) {
+ costs += 2;
+ } else if(is_Proj(spilled)) {
+ costs += 0;
+ } else {
+ costs += 1;
+ }
+ if(parentcosts + costs >= REMAT_COST_LIMIT)
+ return REMAT_COST_LIMIT;
+
+ argremats = 0;
+ for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
+ ir_node *arg = get_irn_n(spilled, i);
+
+ if(is_value_available(env, arg, reloader))
+ continue;
+
+ // we have to rematerialize the argument as well...
+ if(argremats >= 1) {
+ /* we only support rematerializing 1 argument at the moment,
+ * so that we don't have to care about register pressure
+ */
+ return REMAT_COST_LIMIT;
}
+ argremats++;
+ // TODO can we get more accurate costs than +1?
+ costs += check_remat_conditions_costs(env, arg, reloader, parentcosts + costs);
+ if(parentcosts + costs >= REMAT_COST_LIMIT)
+ return REMAT_COST_LIMIT;
}
- return 1;
+ return costs;
}
-#else /* BUGGY_REMAT */
-
-/**
- * A very simple rematerialization checker.
- *
- * @param senv the spill environment
- * @param spill the Spill node
- * @param spilled the node that was spilled
- * @param reloader a irn that requires a reload
- */
-static int check_remat_conditions(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
- const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
+static int check_remat_conditions(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
+ int costs = check_remat_conditions_costs(env, spilled, reloader, 1);
- return get_irn_arity(spilled) == 0 &&
- arch_irn_is(aenv, spilled, rematerializable);
+ return costs < REMAT_COST_LIMIT;
}
-#endif /* BUGGY_REMAT */
-
/**
* Re-materialize a node.
*
* @param spilled the node that was spilled
* @param reloader a irn that requires a reload
*/
-static ir_node *do_remat(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
+static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader) {
+ int i, arity;
ir_node *res;
- ir_node *bl = (is_Block(reloader)) ? reloader : get_nodes_block(reloader);
+ ir_node *bl = get_nodes_block(reloader);
+ ir_node **ins;
+
+ ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
+ for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
+ ir_node *arg = get_irn_n(spilled, i);
- /* recompute the value */
- res = new_ir_node(get_irn_dbg_info(spilled), senv->chordal_env->irg, bl,
+ if(is_value_available(env, arg, reloader)) {
+ ins[i] = arg;
+ } else {
+ ins[i] = do_remat(env, arg, reloader);
+ }
+ }
+
+ /* create a copy of the node */
+ res = new_ir_node(get_irn_dbg_info(spilled), env->chordal_env->irg, bl,
get_irn_op(spilled),
get_irn_mode(spilled),
get_irn_arity(spilled),
- get_irn_in(spilled) + 1);
+ ins);
copy_node_attr(spilled, res);
- DBG((senv->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
+ DBG((env->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
+ ir_printf("Insert remat %+F for %+F before reloader %+F(%s)\n", res, spilled, reloader, get_irg_dump_name(get_irn_irg(reloader)));
/* insert in schedule */
- if (is_Block(reloader)) {
- ir_node *insert = sched_skip(reloader, 0, sched_skip_cf_predicator, (void *) senv->chordal_env->birg->main_env->arch_env);
- sched_add_after(insert, res);
- } else {
- sched_add_before(reloader, res);
- }
+ assert(!is_Block(reloader));
+ sched_add_before(reloader, res);
return res;
}
-void be_spill_phi(spill_env_t *env, ir_node *node) {
- int i, arity;
-
- assert(is_Phi(node));
-
- pset_insert_ptr(env->mem_phis, node);
-
- // create spillinfos for the phi arguments
- get_spillinfo(env, node);
- for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
- ir_node *arg = get_irn_n(node, i);
- get_spillinfo(env, arg);
- }
-}
+/*
+ * ___ _ ____ _ _
+ * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
+ * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
+ * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
+ * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
+ *
+ */
void be_insert_spills_reloads(spill_env_t *env) {
const arch_env_t *arch_env = env->chordal_env->birg->main_env->arch_env;
del_set(env->spills);
env->spills = new_set(cmp_spillinfo, 1024);
}
-
-void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
- spill_info_t *info;
- reloader_t *rel;
-
- assert(sched_is_scheduled(before));
- assert(arch_irn_consider_in_reg_alloc(env->chordal_env->birg->main_env->arch_env, env->cls, to_spill));
-
- info = get_spillinfo(env, to_spill);
-
- if(is_Phi(to_spill)) {
- int i, arity;
- // create spillinfos for the phi arguments
- for(i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
- ir_node *arg = get_irn_n(to_spill, i);
- get_spillinfo(env, arg);
- }
- }
-
- rel = obstack_alloc(&env->obst, sizeof(rel[0]));
- rel->reloader = before;
- rel->next = info->reloaders;
- info->reloaders = rel;
- be_liveness_add_missing(env->chordal_env->lv);
-}
-
-void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
- ir_node *predblock, *last;
-
- /* simply add the reload to the beginning of the block if we only have 1 predecessor
- * (we don't need to check for phis as there can't be any in a block with only 1 pred)
- */
- if(get_Block_n_cfgpreds(block) == 1) {
- assert(!is_Phi(sched_first(block)));
- be_add_reload(env, to_spill, sched_first(block));
- return;
- }
-
- /* We have to reload the value in pred-block */
- predblock = get_Block_cfgpred_block(block, pos);
- last = sched_last(predblock);
-
- /* we might have projs and keepanys behind the jump... */
- while(is_Proj(last) || be_is_Keep(last)) {
- last = sched_prev(last);
- assert(!sched_is_end(last));
- }
- assert(is_cfop(last));
-
- // add the reload before the (cond-)jump
- be_add_reload(env, to_spill, last);
-}
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