+/*
+ * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
/**
- * Project: libFIRM
- * File name: ir/opt/opt_osr.
- * Purpose: Operator Strength Reduction,
- * Keith D. Cooper, L. Taylor Simpson, Christopher A. Vick
- * Author: Michael Beck
- * Modified by:
- * Created: 12.5.2006
- * CVS-ID: $Id$
- * Copyright: (c) 2006 Universität Karlsruhe
- * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ * @file
+ * @brief Operator Strength Reduction.
+ * @date 12.5.2006
+ * @author Michael Beck
+ * @version $Id$
+ * @summary
+ * Implementation of the Operator Strength Reduction algorithm
+ * by Keith D. Cooper, L. Taylor Simpson, Christopher A. Vick.
+ * Extended version.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
-#ifdef HAVE_MALLOC_H
-#include <malloc.h>
-#endif
-#ifdef HAVE_ALLOCA_H
-#include <alloca.h>
-#endif
-
-#include "opt_osr.h"
+#include "adt/pdeq.h"
+#include "iroptimize.h"
#include "irgraph.h"
+#include "ircons.h"
#include "irop_t.h"
-#include "irloop.h"
#include "irdom.h"
+#include "irgmod.h"
#include "irflag_t.h"
#include "irgwalk.h"
+#include "irouts.h"
+#include "iredges.h"
#include "debug.h"
#include "obst.h"
+#include "set.h"
+#include "tv.h"
+#include "hashptr.h"
#include "irtools.h"
+#include "irloop_t.h"
#include "array.h"
+#include "firmstat.h"
+#include "xmalloc.h"
/** The debug handle. */
DEBUG_ONLY(static firm_dbg_module_t *dbg;)
-/* Use the link field to mark IV's */
-#define MARK_LOOP_IV(loop) set_loop_link((loop), (loop))
-#define UNMARK_LOOP_IV(loop) set_loop_link((loop), NULL)
-#define IS_LOOP_IV(loop) (get_loop_link(loop) != NULL)
-
/** A scc. */
typedef struct scc {
- ir_node *head; /**< the head of the list */
- ir_node *header; /**< the header block of this scc */
- int is_iv; /**< true, if this scc is an IV */
+ ir_node *head; /**< the head of the list */
+ tarval *init; /**< the init value iff only one exists. */
+ tarval *incr; /**< the induction variable increment if only a single const exists. */
+ unsigned code; /**< == iro_Add if +incr, iro_Sub if -incr, 0 if not analysed, iro_Bad else */
} scc;
/** A node entry */
/** The environment. */
typedef struct iv_env {
- node_entry *entries; /**< the node entry array */
- struct obstack obst; /**< an obstack for allocations */
- ir_node **stack; /**< the node stack */
- int tos; /**< tos index */
- unsigned nextDFSnum; /**< the current DFS number */
- unsigned replaced; /**< number of replaced ops */
- unsigned POnum; /**< current post order number */
+ struct obstack obst; /**< an obstack for allocations */
+ ir_node **stack; /**< the node stack */
+ int tos; /**< tos index */
+ unsigned nextDFSnum; /**< the current DFS number */
+ unsigned POnum; /**< current post order number */
+ set *quad_map; /**< a map from (op, iv, rc) to node */
+ set *lftr_edges; /**< the set of lftr edges */
+ unsigned replaced; /**< number of replaced ops */
+ unsigned lftr_replaced; /**< number of applied linear function test replacements */
+ unsigned flags; /**< additional flags */
+ /** Function called to process a SCC. */
+ void (*process_scc)(scc *pscc, struct iv_env *env);
} iv_env;
/**
- * Check if irn is an IV.
+ * An entry in the (op, node, node) -> node map.
*/
-static scc *is_iv(ir_node *irn, iv_env *env) {
- int idx = get_irn_idx(irn);
- node_entry *e = &env->entries[idx];
+typedef struct quadruple_t {
+ ir_opcode code; /**< the opcode of the reduced operation */
+ ir_node *op1; /**< the first operand the reduced operation */
+ ir_node *op2; /**< the second operand of the reduced operation */
- return e->pscc && e->pscc->is_iv ? e->pscc : NULL;
+ ir_node *res; /**< the reduced operation */
+} quadruple_t;
+
+/**
+ * A LFTR edge.
+ */
+typedef struct LFTR_edge {
+ ir_node *src; /**< the source node */
+ ir_node *dst; /**< the destination node */
+ ir_opcode code; /**< the opcode that must be applied */
+ ir_node *rc; /**< the region const that must be applied */
+} LFTR_edge;
+
+/* forward */
+static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env);
+
+/**
+ * Compare two LFTR edges.
+ */
+static int LFTR_cmp(const void *e1, const void *e2, size_t size) {
+ const LFTR_edge *l1 = e1;
+ const LFTR_edge *l2 = e2;
+ (void) size;
+
+ return l1->src != l2->src;
+}
+
+/**
+ * Find a LFTR edge.
+ */
+static LFTR_edge *LFTR_find(ir_node *src, iv_env *env) {
+ LFTR_edge key;
+
+ key.src = src;
+
+ return set_find(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
+}
+
+/**
+ * Add a LFTR edge.
+ */
+static void LFTR_add(ir_node *src, ir_node *dst, ir_opcode code, ir_node *rc, iv_env *env) {
+ LFTR_edge key;
+
+ key.src = src;
+ key.dst = dst;
+ key.code = code;
+ key.rc = rc;
+
+ /*
+ * There might be more than one edge here. This is rather bad
+ * because we currently store only one.
+ */
+// assert(LFTR_find(src, env) == NULL);
+ set_insert(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
+}
+
+/**
+ * Gets the node_entry of a node
+ */
+static node_entry *get_irn_ne(ir_node *irn, iv_env *env) {
+ node_entry *e = get_irn_link(irn);
+
+ if (! e) {
+ e = obstack_alloc(&env->obst, sizeof(*e));
+ memset(e, 0, sizeof(*e));
+ set_irn_link(irn, e);
+ }
+ return e;
+}
+
+/**
+ * Gets the scc from an IV.
+ */
+static scc *get_iv_scc(ir_node *iv, iv_env *env) {
+ node_entry *e = get_irn_ne(iv, env);
+ return e->pscc;
+}
+
+/**
+ * Check if irn is an IV.
+ *
+ * @param irn the node to check
+ * @param env the environment
+ *
+ * @returns the header if it is one, NULL else
+ */
+static ir_node *is_iv(ir_node *irn, iv_env *env) {
+ return get_irn_ne(irn, env)->header;
}
/**
* Check if irn is a region constant.
+ * The block or irn must strictly dominate the header block.
+ *
+ * @param irn the node to check
+ * @param header_block the header block of the induction variable
*/
static int is_rc(ir_node *irn, ir_node *header_block) {
ir_node *block = get_nodes_block(irn);
- return block_dominates(block, header_block);
+ return (block != header_block) && block_dominates(block, header_block);
+}
+
+/**
+ * Set compare function for the quad set.
+ */
+static int quad_cmp(const void *e1, const void *e2, size_t size) {
+ const quadruple_t *c1 = e1;
+ const quadruple_t *c2 = e2;
+ (void) size;
+
+ return c1->code != c2->code || c1->op1 != c2->op1 || c1->op2 != c2->op2;
+}
+
+/**
+ * Check if an reduced operation was already calculated.
+ *
+ * @param code the opcode of the operation
+ * @param op1 the first operand of the operation
+ * @param op2 the second operand of the operation
+ * @param env the environment
+ *
+ * @return the already reduced node or NULL if this operation is not yet reduced
+ */
+static ir_node *search(ir_opcode code, ir_node *op1, ir_node *op2, iv_env *env) {
+ quadruple_t key, *entry;
+
+ key.code = code;
+ key.op1 = op1;
+ key.op2 = op2;
+
+ entry = set_find(env->quad_map, &key, sizeof(key),
+ (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
+ if (entry)
+ return entry->res;
+ return NULL;
}
/**
- * Do the replacement operation.
+ * Add an reduced operation.
+ *
+ * @param code the opcode of the operation
+ * @param op1 the first operand of the operation
+ * @param op2 the second operand of the operation
+ * @param result the result of the reduced operation
+ * @param env the environment
+ */
+static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env) {
+ quadruple_t key;
+
+ key.code = code;
+ key.op1 = op1;
+ key.op2 = op2;
+ key.res = result;
+
+ set_insert(env->quad_map, &key, sizeof(key),
+ (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
+}
+
+/**
+ * Find a location where to place a bin-op whose operands are in
+ * block1 and block2.
+ *
+ * @param block1 the block of the first operand
+ * @param block2 the block of the second operand
+ *
+ * Note that we know here that such a place must exists. Moreover, this means
+ * that either block1 dominates block2 or vice versa. So, just return
+ * the "smaller" one.
+ */
+static ir_node *find_location(ir_node *block1, ir_node *block2) {
+ if (block_dominates(block1, block2))
+ return block2;
+ assert(block_dominates(block2, block1));
+ return block1;
+}
+
+/**
+ * Create a node that executes an op1 code op1 operation.
+ *
+ * @param code the opcode to execute
+ * @param db debug info to add to the new node
+ * @param op1 the first operand
+ * @param op2 the second operand
+ * @param mode the mode of the new operation
+ *
+ * @return the newly created node
+ */
+static ir_node *do_apply(ir_opcode code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode) {
+ ir_graph *irg = current_ir_graph;
+ ir_node *result;
+ ir_node *block = find_location(get_nodes_block(op1), get_nodes_block(op2));
+
+ switch (code) {
+ case iro_Mul:
+ result = new_rd_Mul(db, irg, block, op1, op2, mode);
+ break;
+ case iro_Add:
+ result = new_rd_Add(db, irg, block, op1, op2, mode);
+ break;
+ case iro_Sub:
+ result = new_rd_Sub(db, irg, block, op1, op2, mode);
+ break;
+ default:
+ assert(0);
+ result = NULL;
+ }
+ return result;
+}
+
+/**
+ * The Apply operation.
+ *
+ * @param orig the node that represent the original operation and determines
+ * the opcode, debug-info and mode of a newly created one
+ * @param op1 the first operand
+ * @param op2 the second operand
+ * @param env the environment
+ *
+ * @return the newly created node
+ */
+static ir_node *apply(ir_node *header, ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env) {
+ ir_opcode code = get_irn_opcode(orig);
+ ir_node *result = search(code, op1, op2, env);
+
+ if (result == NULL) {
+ dbg_info *db = get_irn_dbg_info(orig);
+ ir_node *op1_header = get_irn_ne(op1, env)->header;
+ ir_node *op2_header = get_irn_ne(op2, env)->header;
+
+ if (op1_header == header && is_rc(op2, op1_header)) {
+ result = reduce(orig, op1, op2, env);
+ }
+ else if (op2_header == header && is_rc(op1, op2_header)) {
+ result = reduce(orig, op2, op1, env);
+ }
+ else {
+ result = do_apply(code, db, op1, op2, get_irn_mode(orig));
+ get_irn_ne(result, env)->header = NULL;
+ }
+ }
+ return result;
+}
+
+/**
+ * The Reduce operation.
+ *
+ * @param orig the node that represent the original operation and determines
+ * the opcode, debug-info and mode of a newly created one
+ * @param iv the induction variable
+ * @param rc the region constant
+ * @param env the environment
+ *
+ * @return the reduced node
+ */
+static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
+ ir_opcode code = get_irn_opcode(orig);
+ ir_node *result = search(code, iv, rc, env);
+
+ if (result == NULL) {
+ node_entry *e, *iv_e;
+ int i, n;
+ ir_mode *mode = get_irn_mode(orig);
+
+ result = exact_copy(iv);
+
+ /* Beware: we must always create a new induction variable with the same mode
+ as the node we are replacing. Especially this means the mode might be changed
+ from P to I and back. This is always possible, because we have only Phi, Add
+ and Sub nodes. */
+ set_irn_mode(result, mode);
+ add(code, iv, rc, result, env);
+ DB((dbg, LEVEL_3, " Created new %+F for %+F (%s %+F)\n", result, iv,
+ get_irn_opname(orig), rc));
+
+ iv_e = get_irn_ne(iv, env);
+ e = get_irn_ne(result, env);
+ e->header = iv_e->header;
+
+ /* create the LFTR edge */
+ LFTR_add(iv, result, code, rc, env);
+
+ n = get_irn_arity(result);
+ for (i = 0; i < n; ++i) {
+ ir_node *o = get_irn_n(result, i);
+
+ e = get_irn_ne(o, env);
+ if (e->header == iv_e->header)
+ o = reduce(orig, o, rc, env);
+ else if (is_Phi(result) || code == iro_Mul)
+ o = apply(iv_e->header, orig, o, rc, env);
+ set_irn_n(result, i, o);
+ }
+ }
+ else {
+ DB((dbg, LEVEL_3, " Already Created %+F for %+F (%s %+F)\n", result, iv,
+ get_irn_opname(orig), rc));
+ }
+ return result;
+}
+
+/**
+ * Update the scc for a newly created IV.
+ */
+static void update_scc(ir_node *iv, node_entry *e, iv_env *env) {
+ scc *pscc = e->pscc;
+ ir_node *header = e->header;
+ waitq *wq = new_waitq();
+
+ DB((dbg, LEVEL_2, " Creating SCC for new an induction variable:\n "));
+ pscc->head = NULL;
+ waitq_put(wq, iv);
+ do {
+ ir_node *irn = waitq_get(wq);
+ node_entry *ne = get_irn_ne(irn, env);
+ int i;
+
+ ne->pscc = pscc;
+ ne->next = pscc->head;
+ pscc->head = irn;
+ DB((dbg, LEVEL_2, " %+F,", irn));
+
+ for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
+ ir_node *pred = get_irn_n(irn, i);
+ node_entry *pe = get_irn_ne(pred, env);
+
+ if (pe->header == header && pe->pscc == NULL) {
+ /* set the pscc here to ensure that the node is NOT enqueued another time */
+ pe->pscc = pscc;
+ waitq_put(wq, pred);
+ }
+ }
+ } while (! waitq_empty(wq));
+ del_waitq(wq);
+ DB((dbg, LEVEL_2, "\n"));
+}
+
+/**
+ * The Replace operation.
*
* @param irn the node that will be replaced
* @param iv the induction variable
* @param rc the region constant
* @param env the environment
*/
-static void replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
+static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
+ ir_node *result;
+
DB((dbg, LEVEL_2, " Replacing %+F\n", irn));
+
+ result = reduce(irn, iv, rc, env);
+ if (result != irn) {
+ node_entry *e;
+
+ hook_strength_red(current_ir_graph, irn);
+ exchange(irn, result);
+ e = get_irn_ne(result, env);
+ if (e->pscc == NULL) {
+ e->pscc = obstack_alloc(&env->obst, sizeof(*e->pscc));
+ memset(e->pscc, 0, sizeof(*e->pscc));
+ update_scc(result, e, env);
+ }
+ ++env->replaced;
+ return 1;
+ }
+ return 0;
}
+#if 0
/**
- * check if a node can be replaced
+ * check if a given node is a mul with 2, 4, 8
*/
-static void check_replace(ir_node *irn, iv_env *env) {
- ir_node *left, *right, *iv, *rc;
- ir_op *op = get_irn_op(irn);
- opcode code = get_op_code(op);
- scc *liv, *riv;
+static int is_x86_shift_const(ir_node *mul) {
+ ir_node *rc;
+
+ if (! is_Mul(mul))
+ return 0;
+
+ /* normalization put constants on the right side */
+ rc = get_Mul_right(mul);
+ if (is_Const(rc)) {
+ tarval *tv = get_Const_tarval(rc);
+
+ if (tarval_is_long(tv)) {
+ long value = get_tarval_long(tv);
+
+ if (value == 2 || value == 4 || value == 8) {
+ /* do not reduce multiplications by 2, 4, 8 */
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+#endif
+
+/**
+ * Check if an IV represents a counter with constant limits.
+ */
+static int is_counter_iv(ir_node *iv, iv_env *env) {
+ node_entry *e = get_irn_ne(iv, env);
+ scc *pscc = e->pscc;
+ ir_node *have_init = NULL;
+ ir_node *have_incr = NULL;
+ ir_opcode code = iro_Bad;
+ ir_node *irn;
+
+ if (pscc->code != 0) {
+ /* already analysed */
+ return pscc->code != iro_Bad;
+ }
+
+ pscc->code = iro_Bad;
+ for (irn = pscc->head; irn != NULL; irn = e->next) {
+ if (is_Add(irn)) {
+ if (have_incr != NULL)
+ return 0;
+
+ have_incr = get_Add_right(irn);
+ if (! is_Const(have_incr)) {
+ have_incr = get_Add_left(irn);
+ if (! is_Const(have_incr))
+ return 0;
+ }
+ code = iro_Add;
+ } else if (is_Sub(irn)) {
+ if (have_incr != NULL)
+ return 0;
+
+ have_incr = get_Sub_right(irn);
+ if (! is_Const(have_incr))
+ return 0;
+ code = iro_Sub;
+ } else if (is_Phi(irn)) {
+ int i;
+
+ for (i = get_Phi_n_preds(irn) - 1; i >= 0; --i) {
+ ir_node *pred = get_Phi_pred(irn, i);
+ node_entry *ne = get_irn_ne(pred, env);
+
+ if (ne->header == e->header)
+ continue;
+ if (have_init != NULL)
+ return 0;
+ have_init = pred;
+ if (! is_Const(pred))
+ return 0;
+ }
+ } else
+ return 0;
+ e = get_irn_ne(irn, env);
+ }
+ pscc->init = get_Const_tarval(have_init);
+ pscc->incr = get_Const_tarval(have_incr);
+ pscc->code = code;
+ return code != iro_Bad;
+}
+
+/**
+ * Check the users of an induction variable for register pressure.
+ */
+static int check_users_for_reg_pressure(ir_node *iv, iv_env *env) {
+ ir_node *irn, *header;
+ ir_node *have_user = NULL;
+ ir_node *have_cmp = NULL;
+ node_entry *e = get_irn_ne(iv, env);
+ scc *pscc = e->pscc;
+
+ header = e->header;
+ for (irn = pscc->head; irn != NULL; irn = e->next) {
+ const ir_edge_t *edge;
+
+ foreach_out_edge(irn, edge) {
+ ir_node *user = get_edge_src_irn(edge);
+ node_entry *ne = get_irn_ne(user, env);
+
+ if (e->header == ne->header) {
+ /* found user from the same IV */
+ continue;
+ }
+ if (is_Cmp(user)) {
+ if (have_cmp != NULL) {
+ /* more than one cmp, for now end here */
+ return 0;
+ }
+ have_cmp = user;
+ } else {
+ /* user is a real user of the IV */
+ if (have_user != NULL) {
+ /* found the second user */
+ return 0;
+ }
+ have_user = user;
+ }
+ }
+ e = get_irn_ne(irn, env);
+ }
+
+ if (have_user == NULL) {
+ /* no user, ignore */
+ return 1;
+ }
+
+ if (have_cmp == NULL) {
+ /* fine, only one user, try to reduce */
+ return 1;
+ }
+ /*
+ * We found one user AND at least one cmp.
+ * We should check here if we can transform the Cmp.
+ *
+ * For now our capabilities for doing linear function test
+ * are limited, so check if the iv has the right form: Only ONE
+ * phi, only one Add/Sub with a Const
+ */
+ if (! is_counter_iv(iv, env))
+ return 0;
+
+ /*
+ * Ok, we have only one increment AND it is a Const, we might be able
+ * to do a linear function test replacement, so go on.
+ */
+ return 1;
+}
+
+/**
+ * Check if a node can be replaced (+, -, *).
+ *
+ * @param irn the node to check
+ * @param env the environment
+ *
+ * @return non-zero if irn should be Replace'd
+ */
+static int check_replace(ir_node *irn, iv_env *env) {
+ ir_node *left, *right, *iv, *rc;
+ ir_op *op = get_irn_op(irn);
+ ir_opcode code = get_op_code(op);
+ ir_node *liv, *riv;
switch (code) {
case iro_Mul:
liv = is_iv(left, env);
riv = is_iv(right, env);
- if (liv && is_rc(right, liv->header)) {
+ if (liv && is_rc(right, liv)) {
iv = left; rc = right;
}
- else if (is_op_commutative(op) &&
- riv && is_rc(left, riv->header)) {
+ else if (riv && is_op_commutative(op) &&
+ is_rc(left, riv)) {
iv = right; rc = left;
}
if (iv) {
- replace(irn, iv, rc, env);
- ++env->replaced;
+ if (env->flags & osr_flag_keep_reg_pressure) {
+ if (! check_users_for_reg_pressure(iv, env))
+ return 0;
+ }
+ return replace(irn, iv, rc, env);
}
break;
+ default:
+ break;
}
+ return 0;
}
/**
- * check which SCC's are induction variables
+ * Check which SCC's are induction variables.
+ *
+ * @param pscc a SCC
+ * @param env the environment
*/
static void classify_iv(scc *pscc, iv_env *env) {
ir_node *irn, *next, *header = NULL;
- node_entry *h, *b;
- int j;
+ node_entry *b, *h = NULL;
+ int j, only_phi, num_outside;
+ ir_node *out_rc;
/* find the header block for this scc */
for (irn = pscc->head; irn; irn = next) {
ir_node *block = get_nodes_block(irn);
next = e->next;
- b = &env->entries[get_irn_idx(block)];
+ b = get_irn_ne(block, env);
if (header) {
if (h->POnum < b->POnum) {
h = b;
}
}
- pscc->header = header;
+ /* check if this scc contains only Phi, Add or Sub nodes */
+ only_phi = 1;
+ num_outside = 0;
+ out_rc = NULL;
for (irn = pscc->head; irn; irn = next) {
- node_entry *e = get_irn_link(irn);
+ node_entry *e = get_irn_ne(irn, env);
next = e->next;
switch (get_irn_opcode(irn)) {
case iro_Add:
case iro_Sub:
+ only_phi = 0;
+ /* fall through */
case iro_Phi:
for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
- ir_node *pred = get_irn_n(irn, j);
- node_entry *pe = &env->entries[get_irn_idx(pred)];
+ ir_node *pred = get_irn_n(irn, j);
+ node_entry *pe = get_irn_ne(pred, env);
if (pe->pscc != e->pscc) {
/* not in the same SCC, must be a region const */
/* not an induction variable */
goto fail;
}
+ if (! out_rc) {
+ out_rc = pred;
+ ++num_outside;
+ } else if (out_rc != pred) {
+ ++num_outside;
+ }
}
}
break;
}
}
/* found an induction variable */
- DB((dbg, LEVEL_2, " Found an induction variable in %+F\n", pscc->head));
- pscc->is_iv = 1;
+ DB((dbg, LEVEL_2, " Found an induction variable:\n "));
+ if (only_phi && num_outside == 1) {
+ /* a phi cycle with only one real predecessor can be collapsed */
+ DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
+
+ for (irn = pscc->head; irn; irn = next) {
+ node_entry *e = get_irn_ne(irn, env);
+ next = e->next;
+ e->header = NULL;
+ exchange(irn, out_rc);
+ }
+ ++env->replaced;
+ return;
+ }
+
+ /* set the header for every node in this scc */
+ for (irn = pscc->head; irn; irn = next) {
+ node_entry *e = get_irn_ne(irn, env);
+ e->header = header;
+ next = e->next;
+ DB((dbg, LEVEL_2, " %+F,", irn));
+ }
+ DB((dbg, LEVEL_2, "\n"));
return;
fail:
for (irn = pscc->head; irn; irn = next) {
- node_entry *e = get_irn_link(irn);
+ node_entry *e = get_irn_ne(irn, env);
next = e->next;
- check_replace(irn, env);
+ e->header = NULL;
}
}
/**
- * Do the replacement: We must do this as an additional step because
- * of our loop-tree structure.
+ * Process a SCC for the operator strength reduction.
+ *
+ * @param pscc the SCC
+ * @param env the environment
*/
-static void find_replacement(ir_loop *loop, iv_env *env) {
- int i, n;
+static void process_scc(scc *pscc, iv_env *env) {
+ ir_node *head = pscc->head;
+ node_entry *e = get_irn_link(head);
- if (! IS_LOOP_IV(loop)) {
- /* do replacements */
- n = get_loop_n_nodes(loop);
- for (i = 0; i < n; ++i) {
- ir_node *irn = get_loop_node(loop, i);
- ir_node *left, *right, *iv, *rc;
- opcode code = get_irn_opcode(irn);
+#ifdef DEBUG_libfirm
+ {
+ ir_node *irn, *next;
- switch (code) {
- case iro_Mul:
- case iro_Add:
- case iro_Sub:
- iv = rc = NULL;
+ DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
+ for (irn = pscc->head; irn; irn = next) {
+ node_entry *e = get_irn_link(irn);
- left = get_binop_left(irn);
- right = get_binop_right(irn);
+ next = e->next;
- if (is_iv(left, env) && is_rc(right, left)) {
- iv = left; rc = right;
- }
- else if (code != iro_Sub &&
- is_iv(right, env) && is_rc(left, right)) {
- iv = right; rc = left;
- }
+ DB((dbg, LEVEL_4, " %+F,", irn));
+ }
+ DB((dbg, LEVEL_4, "\n"));
+ }
+#endif
- if (iv) {
- replace(irn, iv, rc, env);
- ++env->replaced;
+ if (e->next == NULL) {
+ /* this SCC has only a single member */
+ check_replace(head, env);
+ } else {
+ classify_iv(pscc, env);
+ }
+}
+
+/**
+ * If an SCC is a Phi only cycle, remove it.
+ */
+static void remove_phi_cycle(scc *pscc, iv_env *env) {
+ ir_node *irn, *next;
+ int j;
+ ir_node *out_rc;
+
+ /* check if this scc contains only Phi, Add or Sub nodes */
+ out_rc = NULL;
+ for (irn = pscc->head; irn; irn = next) {
+ node_entry *e = get_irn_ne(irn, env);
+
+ next = e->next;
+ if (! is_Phi(irn))
+ return;
+
+ for (j = get_irn_arity(irn) - 1; j >= 0; --j) {
+ ir_node *pred = get_irn_n(irn, j);
+ node_entry *pe = get_irn_ne(pred, env);
+
+ if (pe->pscc != e->pscc) {
+ /* not in the same SCC, must be the only input */
+ if (! out_rc) {
+ out_rc = pred;
+ } else if (out_rc != pred) {
+ return;
}
- break;
}
}
}
- n = get_loop_n_sons(loop);
- for (i = 0; i < n; ++i) {
- ir_loop *child = get_loop_son(loop, i);
- find_replacement(child, env);
+ /* found a Phi cycle */
+ DB((dbg, LEVEL_2, " Found an USELESS Phi cycle:\n "));
+
+ for (irn = pscc->head; irn; irn = next) {
+ node_entry *e = get_irn_ne(irn, env);
+ next = e->next;
+ e->header = NULL;
+ exchange(irn, out_rc);
}
+ ++env->replaced;
}
/**
- * Process a SCC given as a list.
+ * Process a SCC for the Phi cycle removement.
+ *
+ * @param pscc the SCC
+ * @param env the environment
*/
-static void process_scc(scc *pscc, iv_env *env) {
+static void process_phi_only_scc(scc *pscc, iv_env *env) {
ir_node *head = pscc->head;
node_entry *e = get_irn_link(head);
- pscc->is_iv = 0;
-
#ifdef DEBUG_libfirm
{
ir_node *irn, *next;
- DB((dbg, LEVEL_3, " SCC at %p:\n ", pscc));
+ DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
for (irn = pscc->head; irn; irn = next) {
node_entry *e = get_irn_link(irn);
next = e->next;
- DB((dbg, LEVEL_3, " %+F,", irn));
+ DB((dbg, LEVEL_4, " %+F,", irn));
}
- DB((dbg, LEVEL_3, "\n"));
+ DB((dbg, LEVEL_4, "\n"));
}
#endif
- if (e->next == NULL) {
- /* this SCC has only a single member */
- check_replace(head, env);
- }
- else {
- classify_iv(pscc, env);
- }
+ if (e->next != NULL)
+ remove_phi_cycle(pscc, env);
}
+
/**
* Push a node onto the stack.
+ *
+ * @param env the environment
+ * @param n the node to push
*/
static void push(iv_env *env, ir_node *n) {
+ node_entry *e;
+
if (env->tos == ARR_LEN(env->stack)) {
int nlen = ARR_LEN(env->stack) * 2;
ARR_RESIZE(ir_node *, env->stack, nlen);
}
env->stack[env->tos++] = n;
- env->entries[get_irn_idx(n)].in_stack = 1;
+ e = get_irn_ne(n, env);
+ e->in_stack = 1;
}
/**
* pop a node from the stack
*
+ * @param env the environment
+ *
* @return The topmost node
*/
static ir_node *pop(iv_env *env)
{
- ir_node *n = env->stack[--env->tos];
- env->entries[get_irn_idx(n)].in_stack = 0;
- return n;
+ ir_node *n = env->stack[--env->tos];
+ node_entry *e = get_irn_ne(n, env);
+
+ e->in_stack = 0;
+ return n;
}
+/**
+ * Do Tarjan's SCC algorithm and drive OSR.
+ *
+ * @param irn start at this node
+ * @param env the environment
+ */
static void dfs(ir_node *irn, iv_env *env)
{
int i, n;
- node_entry *node = &env->entries[get_irn_idx(irn)];
+ node_entry *node = get_irn_ne(irn, env);
mark_irn_visited(irn);
n = get_irn_arity(irn);
for (i = 0; i < n; ++i) {
ir_node *pred = get_irn_n(irn, i);
- node_entry *o = &env->entries[get_irn_idx(pred)];
+ node_entry *o = get_irn_ne(pred, env);
if (irn_not_visited(pred)) {
dfs(pred, env);
scc *pscc = obstack_alloc(&env->obst, sizeof(*pscc));
ir_node *x;
- pscc->head = NULL;
+ memset(pscc, 0, sizeof(*pscc));
do {
node_entry *e;
x = pop(env);
- e = &env->entries[get_irn_idx(x)];
+ e = get_irn_ne(x, env);
e->pscc = pscc;
e->next = pscc->head;
pscc->head = x;
-
- /* link the node entry for easier access */
- set_irn_link(x, e);
} while (x != irn);
- process_scc(pscc, env);
+ env->process_scc(pscc, env);
}
}
}
/**
- * Do the DFS by starting end the End node
+ * Do the DFS by starting at the End node of a graph.
+ *
+ * @param irg the graph to process
+ * @param env the environment
*/
static void do_dfs(ir_graph *irg, iv_env *env) {
ir_graph *rem = current_ir_graph;
ir_node *end = get_irg_end(irg);
int i, n;
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
+
current_ir_graph = irg;
inc_irg_visited(irg);
if (irn_not_visited(ka))
dfs(ka, env);
}
+
+ ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
+
current_ir_graph = rem;
}
*/
static void assign_po(ir_node *block, void *ctx) {
iv_env *env = ctx;
- int idx = get_irn_idx(block);
+ node_entry *e = get_irn_ne(block, env);
- env->entries[idx].POnum = env->POnum++;
+ e->POnum = env->POnum++;
}
-/* Performs Operator Strength Reduction for the passed graph. */
-void opt_osr(ir_graph *irg) {
- iv_env env;
+/**
+ * Follows the LFTR edges and return the last node in the chain.
+ *
+ * @param irn the node that should be followed
+ * @param env the IV environment
+ *
+ * @note
+ * In the current implementation only the last edge is stored, so
+ * only one chain exists. That's why we might miss some opportunities.
+ */
+static ir_node *followEdges(ir_node *irn, iv_env *env) {
+ for (;;) {
+ LFTR_edge *e = LFTR_find(irn, env);
+ if (e)
+ irn = e->dst;
+ else
+ return irn;
+ }
+}
+
+/**
+ * Apply one LFTR edge operation.
+ * Return NULL if the transformation cannot be done safely without
+ * an Overflow.
+ *
+ * @param iv the induction variable
+ * @param rc the constant that should be translated
+ * @param e the LFTR edge
+ * @param env the IV environment
+ *
+ * @return the translated region constant or NULL
+ * if the translation was not possible
+ *
+ * @note
+ * In the current implementation only the last edge is stored, so
+ * only one chain exists. That's why we might miss some opportunities.
+ */
+static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env) {
+ if (env->flags & osr_flag_lftr_with_ov_check) {
+ tarval *tv_l, *tv_r, *tv, *tv_init, *tv_incr;
+ tarval_int_overflow_mode_t ovmode;
+ scc *pscc;
+
+ if (! is_counter_iv(iv, env)) {
+ DB((dbg, LEVEL_4, " not counter IV"));
+ return NULL;
+ }
+
+ /* overflow can only be decided for Consts */
+ if (! is_Const(e->rc)) {
+ DB((dbg, LEVEL_4, " = UNKNOWN (%+F)", e->rc));
+ return NULL;
+ }
+
+ tv_l = get_Const_tarval(rc);
+ tv_r = get_Const_tarval(e->rc);
+
+ ovmode = tarval_get_integer_overflow_mode();
+ tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
+
+ pscc = get_iv_scc(iv, env);
+ tv_incr = pscc->incr;
+ tv_init = pscc->init;
+
+ /*
+ * Check that no overflow occurs:
+ * init must be transformed without overflow
+ * the new rc must be transformed without overflow
+ * rc +/- incr must be possible without overflow
+ */
+ switch (e->code) {
+ case iro_Mul:
+ tv = tarval_mul(tv_l, tv_r);
+ tv_init = tarval_mul(tv_init, tv_r);
+ tv_incr = tarval_mul(tv_incr, tv_r);
+ DB((dbg, LEVEL_4, " * %+F", tv_r));
+ break;
+ case iro_Add:
+ tv = tarval_add(tv_l, tv_r);
+ tv_init = tarval_add(tv_init, tv_r);
+ DB((dbg, LEVEL_4, " + %+F", tv_r));
+ break;
+ case iro_Sub:
+ tv = tarval_sub(tv_l, tv_r, NULL);
+ tv_init = tarval_sub(tv_init, tv_r, NULL);
+ DB((dbg, LEVEL_4, " - %+F", tv_r));
+ break;
+ default:
+ assert(0);
+ tv = tarval_bad;
+ }
+
+ if (pscc->code == iro_Add) {
+ tv = tarval_add(tv, tv_incr);
+ } else {
+ assert(pscc->code == iro_Sub);
+ tv = tarval_sub(tv, tv_incr, NULL);
+ }
+
+ tarval_set_integer_overflow_mode(ovmode);
+
+ if (tv == tarval_bad || tv_init == tarval_bad) {
+ DB((dbg, LEVEL_4, " = OVERFLOW"));
+ return NULL;
+ }
+ return new_r_Const(current_ir_graph, get_irn_n(rc, -1), get_tarval_mode(tv), tv);
+ }
+ return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(rc));
+}
+
+/**
+ * Applies the operations represented by the LFTR edges to a
+ * region constant and returns the value.
+ * Return NULL if the transformation cannot be done safely without
+ * an Overflow.
+ *
+ * @param iv the IV node that starts the LFTR edge chain
+ * @param rc the region constant that should be translated
+ * @param env the IV environment
+ *
+ * @return the translated region constant or NULL
+ * if the translation was not possible
+ */
+static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
+ if (env->flags & osr_flag_lftr_with_ov_check) {
+ /* overflow can only be decided for Consts */
+ if (! is_counter_iv(iv, env)) {
+ DB((dbg, LEVEL_4, "not counter IV\n", rc));
+ return NULL;
+ }
+ if (! is_Const(rc)) {
+ DB((dbg, LEVEL_4, " = UNKNOWN (%+F)\n", rc));
+ return NULL;
+ }
+ DB((dbg, LEVEL_4, "%+F", get_Const_tarval(rc)));
+ }
- if (! get_opt_strength_red())
+ for (; rc;) {
+ LFTR_edge *e = LFTR_find(iv, env);
+ if (e) {
+ rc = applyOneEdge(iv, rc, e, env);
+ iv = e->dst;
+ }
+ else
+ break;
+ }
+ DB((dbg, LEVEL_3, "\n"));
+ return rc;
+}
+
+/**
+ * Walker, finds Cmp(iv, rc) or Cmp(rc, iv)
+ * and tries to optimize them.
+ */
+static void do_lftr(ir_node *cmp, void *ctx) {
+ iv_env *env = ctx;
+ ir_node *left, *right, *liv, *riv;
+ ir_node *iv, *rc;
+ ir_node *nleft = NULL, *nright = NULL;
+
+ if (!is_Cmp(cmp))
return;
+ left = get_Cmp_left(cmp);
+ right = get_Cmp_right(cmp);
+
+ liv = is_iv(left, env);
+ riv = is_iv(right, env);
+ if (liv && is_rc(right, liv)) {
+ iv = left; rc = right;
+
+ nright = applyEdges(iv, rc, env);
+ if (nright && nright != rc) {
+ nleft = followEdges(iv, env);
+ }
+ }
+ else if (riv && is_rc(left, riv)) {
+ iv = right; rc = left;
+
+ nleft = applyEdges(iv, rc, env);
+ if (nleft && nleft != rc) {
+ nright = followEdges(iv, env);
+ }
+ }
+
+ if (nleft && nright) {
+ DB((dbg, LEVEL_2, " LFTR for %+F\n", cmp));
+ set_Cmp_left(cmp, nleft);
+ set_Cmp_right(cmp, nright);
+ ++env->lftr_replaced;
+ }
+}
+
+/**
+ * do linear function test replacement.
+ *
+ * @param irg the graph that should be optimized
+ * @param env the IV environment
+ */
+static void lftr(ir_graph *irg, iv_env *env) {
+ irg_walk_graph(irg, NULL, do_lftr, env);
+}
+
+/**
+ * Pre-walker: set all node links to NULL and fix the
+ * block of Proj nodes.
+ */
+static void clear_and_fix(ir_node *irn, void *env)
+{
+ (void) env;
+ set_irn_link(irn, NULL);
+
+ if (is_Proj(irn)) {
+ ir_node *pred = get_Proj_pred(irn);
+ set_nodes_block(irn, get_nodes_block(pred));
+ }
+}
+
+/* Performs Operator Strength Reduction for the passed graph. */
+void opt_osr(ir_graph *irg, unsigned flags) {
+ iv_env env;
+ ir_graph *rem;
+ int edges;
+
+ if (! get_opt_strength_red()) {
+ /* only kill Phi cycles */
+ remove_phi_cycles(irg);
+ return;
+ }
+
+ rem = current_ir_graph;
+ current_ir_graph = irg;
+
FIRM_DBG_REGISTER(dbg, "firm.opt.osr");
- firm_dbg_set_mask(dbg, SET_LEVEL_2);
- /* and dominance as well */
+ DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
+
+ obstack_init(&env.obst);
+ env.stack = NEW_ARR_F(ir_node *, 128);
+ env.tos = 0;
+ env.nextDFSnum = 0;
+ env.POnum = 0;
+ env.quad_map = new_set(quad_cmp, 64);
+ env.lftr_edges = new_set(LFTR_cmp, 64);
+ env.replaced = 0;
+ env.lftr_replaced = 0;
+ env.flags = flags;
+ env.process_scc = process_scc;
+
+ /* Clear all links and move Proj nodes into the
+ the same block as it's predecessors.
+ This can improve the placement of new nodes.
+ */
+ irg_walk_graph(irg, NULL, clear_and_fix, NULL);
+
+ /* we need dominance */
assure_doms(irg);
- DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
+ edges = edges_assure(irg);
- env.entries = NEW_ARR_F(node_entry, get_irg_last_idx(irg));
- memset(env.entries, 0, get_irg_last_idx(irg));
+ /* calculate the post order number for blocks. */
+ irg_block_edges_walk(get_irg_start_block(irg), NULL, assign_po, &env);
- obstack_init(&env.obst);
- env.stack = NEW_ARR_F(ir_node *, 128);
- env.tos = 0;
- env.nextDFSnum = 0;
- env.replaced = 0;
- env.POnum = 0;
+ /* calculate the SCC's and drive OSR. */
+ do_dfs(irg, &env);
+
+ if (env.replaced) {
+ /* try linear function test replacements */
+ //lftr(irg, &env); // currently buggy :-(
+ (void) lftr;
- /* calculate the post order number */
- irg_block_walk_graph(irg, NULL, assign_po, &env);
+ set_irg_outs_inconsistent(irg);
+ DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
+ }
+ del_set(env.lftr_edges);
+ del_set(env.quad_map);
+ DEL_ARR_F(env.stack);
+ obstack_free(&env.obst, NULL);
+
+ if (! edges)
+ edges_deactivate(irg);
+
+ current_ir_graph = rem;
+}
+
+/* Remove any Phi cycles with only one real input. */
+void remove_phi_cycles(ir_graph *irg) {
+ iv_env env;
+ ir_graph *rem;
+
+ rem = current_ir_graph;
+ current_ir_graph = irg;
+
+ FIRM_DBG_REGISTER(dbg, "firm.opt.remove_phi");
+
+ DB((dbg, LEVEL_1, "Doing Phi cycle removement for %+F\n", irg));
+
+ obstack_init(&env.obst);
+ env.stack = NEW_ARR_F(ir_node *, 128);
+ env.tos = 0;
+ env.nextDFSnum = 0;
+ env.POnum = 0;
+ env.quad_map = NULL;
+ env.lftr_edges = NULL;
+ env.replaced = 0;
+ env.lftr_replaced = 0;
+ env.flags = 0;
+ env.process_scc = process_phi_only_scc;
+
+ /* Clear all links and move Proj nodes into the
+ the same block as it's predecessors.
+ This can improve the placement of new nodes.
+ */
+ irg_walk_graph(irg, NULL, clear_and_fix, NULL);
+
+ /* we need outs for calculating the post order */
+ assure_irg_outs(irg);
+
+ /* calculate the post order number for blocks. */
+ irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
+
+ /* calculate the SCC's and drive OSR. */
do_dfs(irg, &env);
if (env.replaced) {
set_irg_outs_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
+ DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n", env.replaced));
}
- DB((dbg, LEVEL_1, "Replacements: %u\n\n", env.replaced));
DEL_ARR_F(env.stack);
obstack_free(&env.obst, NULL);
- DEL_ARR_F(env.entries);
+
+ current_ir_graph = rem;
}
projects / libfirm / blobdiff