+/*
+ * Copyright (C) 1995-2007 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.
*/
#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 "iroptimize.h"
#include "irgraph.h"
#include "ircons.h"
#include "irop_t.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;)
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;
/**
* An entry in the (op, node, node) -> node map.
*/
-typedef struct quad_t {
- 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 */
+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 */
- ir_node *res; /**< the reduced operation */
-} quad_t;
+ 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 */
- opcode code; /**< the opcode that must be applied */
- ir_node *rc; /**< the region const that must be applied */
+ 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 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;
}
+#if 0
/**
* Find a LFTR edge.
*/
return set_find(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
}
+#endif
/**
* Add a LFTR edge.
*/
-static void LFTR_add(ir_node *src, ir_node *dst, opcode code, ir_node *rc, iv_env *env) {
+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;
* Set compare function for the quad set.
*/
static int quad_cmp(const void *e1, const void *e2, size_t size) {
- const quad_t *c1 = e1;
- const quad_t *c2 = e2;
+ 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;
}
*
* @return the already reduced node or NULL if this operation is not yet reduced
*/
-static ir_node *search(opcode code, ir_node *op1, ir_node *op2, iv_env *env) {
- quad_t key, *entry;
+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;
* @param result the result of the reduced operation
* @param env the environment
*/
-static void add(opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env) {
- quad_t key;
+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;
*
* @return the newly created node
*/
-static ir_node *do_apply(opcode code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode) {
+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));
* 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
+ * @param env the environment
*
* @return the newly created node
*/
static ir_node *apply(ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env) {
- opcode code = get_irn_opcode(orig);
+ ir_opcode code = get_irn_opcode(orig);
ir_node *result = search(code, op1, op2, env);
if (! result) {
}
else {
result = do_apply(code, db, op1, op2, get_irn_mode(orig));
- get_irn_ne(result, env)->header = NULL;
- }
+ get_irn_ne(result, env)->header = NULL; }
}
return result;
}
* @return the reduced node
*/
static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
- opcode code = get_irn_opcode(orig);
+ ir_opcode code = get_irn_opcode(orig);
ir_node *result = search(code, iv, rc, env);
if (! result) {
ir_mode *mode = get_irn_mode(orig);
result = exact_copy(iv);
- if (mode_is_reference(mode)) {
- /* bad case: we replace a reference mode calculation.
- assure that the new IV will be a reference one */
- set_irn_mode(result, mode);
- }
+
+ /* 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));
else if (is_Phi(result))
o = apply(orig, o, rc, env);
else {
- switch (code) {
- case iro_Mul:
+ if (code == iro_Mul)
o = apply(orig, o, rc, env);
- break;
- }
}
set_irn_n(result, i, o);
}
* @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, *iv_e;
-
- hook_strength_red(current_ir_graph, irn);
- exchange(irn, result);
- e = get_irn_ne(result, env);
- iv_e = get_irn_ne(iv, env);
- e->header = iv_e->header;
+ ir_loop *iv_loop = get_irn_loop(get_nodes_block(iv));
+ ir_loop *irn_loop = get_irn_loop(get_nodes_block(irn));
+
+ /* only replace nodes that are in the same (or deeper loops) */
+ if (get_loop_depth(irn_loop) >= get_loop_depth(iv_loop)) {
+ DB((dbg, LEVEL_2, " Replacing %+F\n", irn));
+
+ result = reduce(irn, iv, rc, env);
+ if (result != irn) {
+ node_entry *e, *iv_e;
+
+ hook_strength_red(current_ir_graph, irn);
+ exchange(irn, result);
+ e = get_irn_ne(result, env);
+ iv_e = get_irn_ne(iv, env);
+ e->header = iv_e->header;
+ }
+ return 1;
}
+ return 0;
}
/**
* @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);
- opcode code = get_op_code(op);
- ir_node *liv, *riv;
+ 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:
}
if (iv) {
- replace(irn, iv, rc, env);
- ++env->replaced;
- return 1;
+ if (code == iro_Mul && env->flags & osr_flag_ignore_x86_shift) {
+ 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 */
+ break;
+ }
+ }
+ }
+ }
+
+ return replace(irn, iv, rc, env);
}
break;
+ default:
+ break;
}
return 0;
}
*/
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) {
}
/* 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_ne(irn, env);
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);
/* 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:\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) {
}
/**
- * Process a SCC.
+ * Process a SCC for the operator strength reduction.
*
* @param pscc the SCC
* @param env the environment
if (e->next == NULL) {
/* this SCC has only a single member */
check_replace(head, env);
- }
- else {
+ } 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;
+ }
+ }
+ }
+ }
+ /* 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 for the Phi cycle removement.
+ *
+ * @param pscc the SCC
+ * @param env the environment
+ */
+static void process_phi_only_scc(scc *pscc, iv_env *env) {
+ ir_node *head = pscc->head;
+ node_entry *e = get_irn_link(head);
+
+#ifdef DEBUG_libfirm
+ {
+ ir_node *irn, *next;
+
+ 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_4, " %+F,", irn));
+ }
+ DB((dbg, LEVEL_4, "\n"));
+ }
+#endif
+
+ if (e->next != NULL)
+ remove_phi_cycle(pscc, env);
+}
+
+
/**
* Push a node onto the stack.
*
*/
static ir_node *pop(iv_env *env)
{
- ir_node *n = env->stack[--env->tos];
- node_entry *e = get_irn_ne(n, env);
+ ir_node *n = env->stack[--env->tos];
+ node_entry *e = get_irn_ne(n, env);
- e->in_stack = 0;
- return n;
+ e->in_stack = 0;
+ return n;
}
/**
pscc->head = x;
} while (x != irn);
- process_scc(pscc, env);
+ env->process_scc(pscc, env);
}
}
}
e->POnum = env->POnum++;
}
+#if 0
/**
* Follows the LFTR edges and return the last node in the chain.
*
iv = left; rc = right;
nright = applyEdges(iv, rc, env);
- if (nright) {
+ if (nright && nright != rc) {
nleft = followEdges(iv, env);
}
}
iv = right; rc = left;
nleft = applyEdges(iv, rc, env);
- if (nleft) {
+ if (nleft && nleft != rc) {
nright = followEdges(iv, env);
}
}
static void lftr(ir_graph *irg, iv_env *env) {
irg_walk_graph(irg, NULL, do_lftr, env);
}
+#endif
/**
* Pre-walker: set all node links to NULL and fix the
*/
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_irn_n(irn, -1, get_irn_n(pred, -1));
+ 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;
+ iv_env env;
+ ir_graph *rem;
- if (! get_opt_strength_red())
+ 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_3);
DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
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.
if (env.replaced) {
/* try linear function test replacements */
- lftr(irg, &env);
+ //lftr(irg, &env);
set_irg_outs_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
-
DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
}
del_set(env.quad_map);
DEL_ARR_F(env.stack);
obstack_free(&env.obst, NULL);
+
+ 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 dominance */
+ 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);
+ DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n", env.replaced));
+ }
+
+ DEL_ARR_F(env.stack);
+ obstack_free(&env.obst, NULL);
+
+ current_ir_graph = rem;
}
projects / libfirm / blobdiff