/*
- * Project: libFIRM
- * File name: ir/opt/tailrec.c
- * Purpose: tail-recursion optimization
- * Author: Michael Beck
- * Modified by:
- * Created: 08.06.2004
- * CVS-ID: $Id$
- * Copyright: (c) 2002-2004 Universität Karlsruhe
- * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ * 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.
*/
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
+/**
+ * @file
+ * @brief Tail-recursion call optimization.
+ * @date 08.06.2004
+ * @author Michael Beck
+ * @version $Id$
+ */
+#include "config.h"
+
+#include <string.h>
#include <assert.h>
-#include "tailrec.h"
-#include "array.h"
-#include "irprog.h"
+
+#include "debug.h"
+#include "iroptimize.h"
+#include "scalar_replace.h"
+#include "array_t.h"
+#include "irprog_t.h"
#include "irgwalk.h"
#include "irgmod.h"
#include "irop.h"
#include "irgraph_t.h"
#include "ircons.h"
#include "irflag.h"
-#include "tv.h"
-#include "firmstat.h"
+#include "trouts.h"
+#include "irouts.h"
+#include "irhooks.h"
+#include "ircons_t.h"
+
+DEBUG_ONLY(static firm_dbg_module_t *dbg);
/**
- * the environment for colelcting data
+ * the environment for collecting data
*/
typedef struct _collect_t {
- ir_node *proj_X; /**< initial exec proj */
- ir_node *block; /**< old first block */
- int blk_idx; /**< cfgpred index of the initial exec in block */
- ir_node *proj_m; /**< linked list of memory from start proj's */
- ir_node *proj_data; /**< linked list of all parameter access proj's */
+ ir_node *proj_X; /**< initial exec proj */
+ ir_node *block; /**< old first block */
+ int blk_idx; /**< cfgpred index of the initial exec in block */
+ ir_node *proj_m; /**< memory from start proj's */
+ ir_node *proj_data; /**< linked list of all parameter access proj's */
} collect_t;
/**
- * walker for collecting data
+ * walker for collecting data, fills a collect_t environment
*/
-static void collect_data(ir_node *node, void *env)
-{
- collect_t *data = env;
- ir_node *pred;
- ir_op *op;
-
- switch (get_irn_opcode(node)) {
- case iro_Proj:
- pred = get_Proj_pred(node);
-
- op = get_irn_op(pred);
- if (op == op_Proj) {
- ir_node *start = get_Proj_pred(pred);
-
- if (get_irn_op(start) == op_Start) {
- if (get_Proj_proj(pred) == pn_Start_T_args) {
- /* found Proj(ProjT(Start)) */
- set_irn_link(node, data->proj_data);
- data->proj_data = node;
+static void collect_data(ir_node *node, void *env) {
+ collect_t *data = env;
+ ir_node *pred;
+ ir_op *op;
+
+ switch (get_irn_opcode(node)) {
+ case iro_Proj:
+ pred = get_Proj_pred(node);
+
+ op = get_irn_op(pred);
+ if (op == op_Proj) {
+ ir_node *start = get_Proj_pred(pred);
+
+ if (is_Start(start)) {
+ if (get_Proj_proj(pred) == pn_Start_T_args) {
+ /* found Proj(ProjT(Start)) */
+ set_irn_link(node, data->proj_data);
+ data->proj_data = node;
+ }
+ }
+ } else if (op == op_Start) {
+ if (get_Proj_proj(node) == pn_Start_X_initial_exec) {
+ /* found ProjX(Start) */
+ data->proj_X = node;
+ }
+ }
+ break;
+ case iro_Block: {
+ int i, n_pred = get_Block_n_cfgpreds(node);
+
+ /*
+ * the first block has the initial exec as cfg predecessor
+ */
+ if (node != get_irg_start_block(current_ir_graph)) {
+ for (i = 0; i < n_pred; ++i) {
+ if (get_Block_cfgpred(node, i) == data->proj_X) {
+ data->block = node;
+ data->blk_idx = i;
+ break;
+ }
+ }
+ }
+ break;
}
- }
- }
- else if (op == op_Start) {
- switch (get_Proj_proj(node)) {
- case pn_Start_M:
- /* found ProjM(Start) */
- set_irn_link(node, data->proj_m);
- data->proj_m = node;
- break;
- case pn_Start_X_initial_exec:
- /* found ProjX(Start) */
- data->proj_X = node;
- break;
default:
- break;
- }
- }
- break;
- case iro_Block: {
- int i, n_pred = get_Block_n_cfgpreds(node);
-
- /*
- * the first block has the initial exec as cfg predecessor
- */
- if (node != current_ir_graph->start_block) {
- for (i = 0; i < n_pred; ++i) {
- if (get_Block_cfgpred(node, i) == data->proj_X) {
- data->block = node;
- data->blk_idx = i;
- break;
+ break;
}
- }
- }
- break;
- }
- default:
- break;
- }
}
+typedef enum tail_rec_variants {
+ TR_DIRECT, /**< direct return value, i.e. return func(). */
+ TR_ADD, /**< additive return value, i.e. return x +/- func() */
+ TR_MUL, /**< multiplicative return value, i.e. return x * func() or return -func() */
+ TR_BAD, /**< any other transformation */
+ TR_UNKNOWN /**< during construction */
+} tail_rec_variants;
+
+typedef struct tr_env {
+ int n_tail_calls; /**< number of tail calls found */
+ int n_ress; /**< number of return values */
+ tail_rec_variants *variants; /**< return value variants */
+ ir_node *rets; /**< list of returns that can be transformed */
+} tr_env;
+
+
/**
* do the graph reconstruction for tail-recursion elimination
*
* @param rets linked list of all rets
* @param n_tail_calls number of tail-recursion calls
*/
-static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls)
-{
- ir_graph *rem_irg = current_ir_graph;
- ir_node *end_block = irg->end_block;
- ir_node *block, *jmp, *call, *calls;
- ir_node **in;
- ir_node **phis;
- ir_node ***call_params;
- ir_node *p;
- int i, j, n_params;
- collect_t data;
- int rem = get_optimize();
-
- assert(n_tail_calls);
-
- /* we add nwe nodes, so the outs are inconsistant */
- set_irg_outs_inconsistent(irg);
-
- /* we add new blocks and change the control flow */
- set_irg_dom_inconsistent(irg);
-
- /* we add a new loop */
- set_irg_loopinfo_inconsistent(irg);
-
- set_optimize(0);
-
- /* collect needed data */
- data.proj_X = NULL;
- data.block = NULL;
- data.blk_idx = -1;
- data.proj_m = NULL;
- data.proj_data = NULL;
- irg_walk_graph(irg, NULL, collect_data, &data);
-
- /* check number of arguments */
- call = get_irn_link(end_block);
- n_params = get_Call_n_params(call);
-
- assert(data.proj_X && "Could not find initial exec from Start");
- assert(data.block && "Could not find first block");
- assert(data.proj_m && "Could not find ProjM(Start)");
- assert((data.proj_data || n_params == 0) && "Could not find Proj(ProjT(Start)) of non-void function");
-
- current_ir_graph = irg;
-
- /* allocate in's for phi and block construction */
- NEW_ARR_A(ir_node *, in, n_tail_calls + 1);
-
- in[0] = data.proj_X;
-
- /* turn Return's into Jmp's */
- for (i = 1, p = rets; p; p = get_irn_link(p)) {
- ir_node *jmp;
-
- set_cur_block(get_nodes_block(p));
- jmp = new_Jmp();
-
- exchange(p, new_Bad());
- in[i++] = jmp;
-
- add_End_keepalive(get_irg_end(irg), jmp);
- }
-
- /* create a new block at start */
- block = new_Block(n_tail_calls + 1, in);
- jmp = new_Jmp();
-
- /* the old first block is now the second one */
- set_Block_cfgpred(data.block, data.blk_idx, jmp);
-
- /* allocate phi's, position 0 contains the memory phi */
- NEW_ARR_A(ir_node *, phis, n_params + 1);
-
- /* build the memory phi */
- i = 0;
- in[i] = new_rd_Proj(NULL, irg, irg->start_block, irg->start, mode_M, pn_Start_M);
- ++i;
-
- for (calls = call; calls; calls = get_irn_link(calls)) {
- in[i] = get_Call_mem(calls);
- ++i;
- }
- phis[0] = new_rd_Phi(NULL, irg, block, n_tail_calls + 1, in, mode_M);
-
- /* build the data phi's */
- if (n_params > 0) {
- ir_node *calls;
-
- NEW_ARR_A(ir_node **, call_params, n_params);
-
- /* collect all parameters */
- for (i = 0, calls = call; calls; calls = get_irn_link(calls)) {
- call_params[i] = get_Call_param_arr(calls);
- ++i;
- }
-
- /* build new projs and Phi's */
- for (i = 0; i < n_params; ++i) {
- ir_mode *mode = get_irn_mode(call_params[0][i]);
-
- in[0] = new_rd_Proj(NULL, irg, block, irg->args, mode, i);
- for (j = 0; j < n_tail_calls; ++j)
- in[j + 1] = call_params[j][i];
-
- phis[i + 1] = new_rd_Phi(NULL, irg, block, n_tail_calls + 1, in, mode);
- }
- }
+static void do_opt_tail_rec(ir_graph *irg, tr_env *env) {
+ ir_node *end_block = get_irg_end_block(irg);
+ ir_node *block, *jmp, *call, *calls;
+ ir_node **in;
+ ir_node **phis;
+ ir_node ***call_params;
+ ir_node *p, *n;
+ int i, j, n_params, n_locs;
+ collect_t data;
+ int rem = get_optimize();
+ ir_entity *ent = get_irg_entity(irg);
+ ir_type *method_tp = get_entity_type(ent);
+ ir_graph *old = current_ir_graph;
+
+ current_ir_graph = irg;
+
+ assert(env->n_tail_calls > 0);
+
+ /* we add new nodes, so the outs are inconsistent */
+ set_irg_outs_inconsistent(irg);
+
+ /* we add new blocks and change the control flow */
+ set_irg_doms_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+
+ /* we add a new loop */
+ set_irg_loopinfo_inconsistent(irg);
+
+ /* calls are removed */
+ set_trouts_inconsistent();
+
+ /* we must build some new nodes WITHOUT CSE */
+ set_optimize(0);
+
+ /* collect needed data */
+ data.proj_X = NULL;
+ data.block = NULL;
+ data.blk_idx = -1;
+ data.proj_m = get_irg_initial_mem(irg);
+ data.proj_data = NULL;
+ irg_walk_graph(irg, NULL, collect_data, &data);
+
+ /* check number of arguments */
+ call = get_irn_link(end_block);
+ n_params = get_Call_n_params(call);
+
+ assert(data.proj_X && "Could not find initial exec from Start");
+ assert(data.block && "Could not find first block");
+ assert(data.proj_m && "Could not find initial memory");
+ assert((data.proj_data || n_params == 0) && "Could not find Proj(ProjT(Start)) of non-void function");
+
+ /* allocate in's for phi and block construction */
+ NEW_ARR_A(ir_node *, in, env->n_tail_calls + 1);
+
+ in[0] = data.proj_X;
+
+ /* turn Return's into Jmp's */
+ for (i = 1, p = env->rets; p; p = n) {
+ ir_node *block = get_nodes_block(p);
+
+ n = get_irn_link(p);
+ in[i++] = new_r_Jmp(irg, block);
+
+ // exchange(p, new_r_Bad(irg));
+
+ /* we might generate an endless loop, so add
+ * the block to the keep-alive list */
+ add_End_keepalive(get_irg_end(irg), block);
+ }
+
+ /* create a new block at start */
+ block = new_r_Block(irg, env->n_tail_calls + 1, in);
+ jmp = new_r_Jmp(irg, block);
+
+ /* the old first block is now the second one */
+ set_Block_cfgpred(data.block, data.blk_idx, jmp);
+
+ /* allocate phi's, position 0 contains the memory phi */
+ NEW_ARR_A(ir_node *, phis, n_params + 1);
+
+ /* build the memory phi */
+ i = 0;
+ in[i] = new_r_Proj(irg, get_irg_start_block(irg), get_irg_start(irg), mode_M, pn_Start_M);
+ set_irg_initial_mem(irg, in[i]);
+ ++i;
- /*
- * ok, we are here, so we have build and collected all needed Phi's
- * now exchange all Projs into links to Phi
- */
- for (p = data.proj_m; p; p = get_irn_link(p)) {
- exchange(p, phis[0]);
- }
- for (p = data.proj_data; p; p = get_irn_link(p)) {
- long proj = get_Proj_proj(p);
+ for (calls = call; calls; calls = get_irn_link(calls)) {
+ in[i] = get_Call_mem(calls);
+ ++i;
+ }
+ assert(i == env->n_tail_calls + 1);
+
+ phis[0] = new_r_Phi(irg, block, env->n_tail_calls + 1, in, mode_M);
+
+ /* build the data Phi's */
+ if (n_params > 0) {
+ ir_node *calls;
+ ir_node *args;
+ ir_node *args_bl;
+
+ NEW_ARR_A(ir_node **, call_params, env->n_tail_calls);
+
+ /* collect all parameters */
+ for (i = 0, calls = call; calls; calls = get_irn_link(calls)) {
+ call_params[i] = get_Call_param_arr(calls);
+ ++i;
+ }
+
+ /* build new Proj's and Phi's */
+ args = get_irg_args(irg);
+ args_bl = get_nodes_block(args);
+ for (i = 0; i < n_params; ++i) {
+ ir_mode *mode = get_type_mode(get_method_param_type(method_tp, i));
+
+ in[0] = new_r_Proj(irg, args_bl, args, mode, i);
+ for (j = 0; j < env->n_tail_calls; ++j)
+ in[j + 1] = call_params[j][i];
+
+ phis[i + 1] = new_r_Phi(irg, block, env->n_tail_calls + 1, in, mode);
+ }
+ }
- assert(0 <= proj && proj < n_params);
- exchange(p, phis[proj + 1]);
- }
+ /*
+ * ok, we are here, so we have build and collected all needed Phi's
+ * now exchange all Projs into links to Phi
+ */
+ exchange(data.proj_m, phis[0]);
+ for (p = data.proj_data; p; p = n) {
+ long proj = get_Proj_proj(p);
+
+ assert(0 <= proj && proj < n_params);
+ n = get_irn_link(p);
+ exchange(p, phis[proj + 1]);
+ }
+
+ /* tail recursion was done, all info is invalid */
+ set_irg_doms_inconsistent(irg);
+ set_irg_outs_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+ set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_inconsistent);
+ set_trouts_inconsistent();
+ set_irg_callee_info_state(irg, irg_callee_info_inconsistent);
+
+ set_optimize(rem);
+
+ /* check if we need new values */
+ n_locs = 0;
+ for (i = 0; i < env->n_ress; ++i) {
+ if (env->variants[i] != TR_DIRECT)
+ ++n_locs;
+ }
- current_ir_graph = rem_irg;
- set_optimize(rem);
+ if (n_locs > 0) {
+ ir_node *bad, *start_block;
+ ir_node **in;
+ ir_mode **modes;
+
+ NEW_ARR_A(ir_node *, in, n_locs);
+ NEW_ARR_A(ir_mode *, modes, n_locs);
+ ssa_cons_start(irg, n_locs);
+
+ start_block = get_irg_start_block(irg);
+ set_cur_block(start_block);
+
+ for (i = 0; i < env->n_ress; ++i) {
+ ir_type *tp = get_method_res_type(method_tp, i);
+ ir_mode *mode = get_type_mode(tp);
+
+ modes[i] = mode;
+ if (env->variants[i] == TR_ADD) {
+ set_value(i, new_Const(mode, get_mode_null(mode)));
+ } else if (env->variants[i] == TR_MUL) {
+ set_value(i, new_Const(mode, get_mode_one(mode)));
+ }
+ }
+ mature_immBlock(start_block);
+
+ /* no: we can kill all returns */
+ bad = get_irg_bad(irg);
+
+ for (p = env->rets; p; p = n) {
+ ir_node *block = get_nodes_block(p);
+ ir_node *call, *mem, *jmp, *tuple;
+
+ set_cur_block(block);
+ n = get_irn_link(p);
+
+ call = skip_Proj(get_Return_mem(p));
+ assert(is_Call(call));
+
+ mem = get_Call_mem(call);
+
+ /* create a new jump, free of CSE */
+ set_optimize(0);
+ jmp = new_Jmp();
+ set_optimize(rem);
+
+ for (i = 0; i < env->n_ress; ++i) {
+ if (env->variants[i] != TR_DIRECT) {
+ in[i] = get_value(i, modes[i]);
+ } else {
+ in[i] = bad;
+ }
+ }
+ /* create a new tuple for the return values */
+ tuple = new_Tuple(env->n_ress, in);
+
+ turn_into_tuple(call, pn_Call_max);
+ set_Tuple_pred(call, pn_Call_M, mem);
+ set_Tuple_pred(call, pn_Call_X_regular, jmp);
+ set_Tuple_pred(call, pn_Call_X_except, bad);
+ set_Tuple_pred(call, pn_Call_T_result, tuple);
+ set_Tuple_pred(call, pn_Call_M_except, mem);
+ set_Tuple_pred(call, pn_Call_P_value_res_base, bad);
+
+ for (i = 0; i < env->n_ress; ++i) {
+ ir_node *res = get_Return_res(p, i);
+ if (env->variants[i] != TR_DIRECT) {
+ set_value(i, res);
+ }
+ }
+
+ exchange(p, bad);
+ }
+
+ /* finally fix all other returns */
+ end_block = get_irg_end_block(irg);
+ for (i = get_Block_n_cfgpreds(end_block) - 1; i >= 0; --i) {
+ ir_node *ret = get_Block_cfgpred(end_block, i);
+
+ /* search all Returns of a block */
+ if (! is_Return(ret))
+ continue;
+
+ set_cur_block(get_nodes_block(ret));
+ for (j = 0; j < env->n_ress; ++j) {
+ ir_node *pred = get_Return_res(ret, j);
+ ir_node *n;
+
+ switch (env->variants[j]) {
+ case TR_DIRECT:
+ continue;
+
+ case TR_ADD:
+ n = get_value(j, modes[j]);
+ n = new_Add(n, pred, modes[j]);
+ set_Return_res(ret, j, n);
+ break;
+
+ case TR_MUL:
+ n = get_value(j, modes[j]);
+ n = new_Mul(n, pred, modes[j]);
+ set_Return_res(ret, j, n);
+ break;
+
+ default:
+ assert(!"unexpected tail recursion variant");
+ }
+ }
+ }
+ ssa_cons_finish(irg);
+ } else {
+ ir_node *bad = get_irg_bad(irg);
+
+ /* no: we can kill all returns */
+ for (p = env->rets; p; p = n) {
+ n = get_irn_link(p);
+ exchange(p, bad);
+ }
+ }
+ current_ir_graph = old;
}
+/**
+ * Check the lifetime of locals in the given graph.
+ * Tail recursion can only be done, if we can prove that
+ * the lifetime of locals end with the recursive call.
+ * We do this by checking that no address of a local variable is
+ * stored or transmitted as an argument to a call.
+ *
+ * @return non-zero if it's ok to do tail recursion
+ */
+static int check_lifetime_of_locals(ir_graph *irg) {
+ ir_node *irg_frame, *irg_val_param_base;
+ int i;
+
+ irg_frame = get_irg_frame(irg);
+ for (i = get_irn_n_outs(irg_frame) - 1; i >= 0; --i) {
+ ir_node *succ = get_irn_out(irg_frame, i);
+
+ if (is_Sel(succ) && is_address_taken(succ))
+ return 0;
+ }
+
+ /* Check if we have compound arguments.
+ For now, we cannot handle them, */
+ irg_val_param_base = get_irg_value_param_base(irg);
+ if (get_irn_n_outs(irg_val_param_base) > 0)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * Examine irn and detect the recursion variant.
+ */
+static tail_rec_variants find_variant(ir_node *irn, ir_node *call) {
+ ir_node *a, *b;
+ tail_rec_variants va, vb, res;
+
+ if (skip_Proj(skip_Proj(irn)) == call) {
+ /* found it */
+ return TR_DIRECT;
+ }
+ switch (get_irn_opcode(irn)) {
+ case iro_Add:
+ /* try additive */
+ a = get_Add_left(irn);
+ if (get_irn_MacroBlock(a) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ va = TR_UNKNOWN;
+ } else {
+ va = find_variant(a, call);
+ if (va == TR_BAD)
+ return TR_BAD;
+ }
+ b = get_Add_right(irn);
+ if (get_irn_MacroBlock(b) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ vb = TR_UNKNOWN;
+ } else {
+ vb = find_variant(b, call);
+ if (vb == TR_BAD)
+ return TR_BAD;
+ }
+ if (va == vb) {
+ res = va;
+ }
+ else if (va == TR_UNKNOWN)
+ res = vb;
+ else if (vb == TR_UNKNOWN)
+ res = va;
+ else {
+ /* they are different but none is TR_UNKNOWN -> incompatible */
+ return TR_BAD;
+ }
+ if (res == TR_DIRECT || res == TR_ADD)
+ return TR_ADD;
+ /* not compatible */
+ return TR_BAD;
+
+ case iro_Sub:
+ /* try additive, but return value must be left */
+ a = get_Sub_left(irn);
+ if (get_irn_MacroBlock(a) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ va = TR_UNKNOWN;
+ } else {
+ va = find_variant(a, call);
+ if (va == TR_BAD)
+ return TR_BAD;
+ }
+ b = get_Sub_right(irn);
+ if (get_irn_MacroBlock(b) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ vb = TR_UNKNOWN;
+ } else {
+ vb = find_variant(b, call);
+ if (vb != TR_UNKNOWN)
+ return TR_BAD;
+ }
+ res = va;
+ if (res == TR_DIRECT || res == TR_ADD)
+ return res;
+ /* not compatible */
+ return TR_BAD;
+
+ case iro_Mul:
+ /* try multiplicative */
+ a = get_Mul_left(irn);
+ if (get_irn_MacroBlock(a) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ va = TR_UNKNOWN;
+ } else {
+ va = find_variant(a, call);
+ if (va == TR_BAD)
+ return TR_BAD;
+ }
+ b = get_Mul_right(irn);
+ if (get_irn_MacroBlock(b) != get_irn_MacroBlock(call)) {
+ /* we are outside, ignore */
+ vb = TR_UNKNOWN;
+ } else {
+ vb = find_variant(b, call);
+ if (vb == TR_BAD)
+ return TR_BAD;
+ }
+ if (va == vb) {
+ res = va;
+ }
+ else if (va == TR_UNKNOWN)
+ res = vb;
+ else if (vb == TR_UNKNOWN)
+ res = va;
+ else {
+ /* they are different but none is TR_UNKNOWN -> incompatible */
+ return TR_BAD;
+ }
+ if (res == TR_DIRECT || res == TR_MUL)
+ return TR_MUL;
+ /* not compatible */
+ return TR_BAD;
+
+ case iro_Minus:
+ /* try multiplicative */
+ a = get_Minus_op(irn);
+ res = find_variant(a, call);
+ if (res == TR_DIRECT)
+ return TR_MUL;
+ if (res == TR_MUL || res == TR_UNKNOWN)
+ return res;
+ /* not compatible */
+ return TR_BAD;
+
+ default:
+ return TR_UNKNOWN;
+ }
+}
+
+
/*
* convert simple tail-calls into loops
*/
-void opt_tail_rec_irg(ir_graph *irg)
-{
- ir_node *end_block = irg->end_block;
- int n_preds;
- int i, n_tail_calls = 0;
- ir_node *rets = NULL;
-
- if (! get_opt_tail_recursion() || ! get_opt_optimize())
- return;
-
- set_irn_link(end_block, NULL);
-
- n_preds = get_Block_n_cfgpreds(end_block);
- for (i = 0; i < n_preds; ++i) {
- ir_node *ret = get_Block_cfgpred(end_block, i);
- ir_node *proj_m, *call, *call_ptr;
- tarval *tv;
- entity *ent;
- int j, n_ress;
- ir_node **ress;
-
- /* search all returns of a block */
- if (get_irn_op(ret) != op_Return)
- continue;
-
- /* check, if it's a Return self() */
- proj_m = get_Return_mem(ret);
-
- if (get_irn_op(proj_m) != op_Proj)
- continue;
-
- call = get_Proj_pred(proj_m);
- if (get_irn_op(call) != op_Call)
- continue;
-
- /* check if it's a recursive call */
- call_ptr = get_Call_ptr(call);
-
- if (get_irn_op(call_ptr) != op_SymConst)
- continue;
-
- ent = get_SymConst_entity(call_ptr);
- if (!ent || get_entity_irg(ent) != irg)
- continue;
-
- /* ok, mem is routed to a recursive call, check return args */
- n_ress = get_Return_n_ress(ret);
- ress = get_Return_res_arr(ret);
-
- for (j = 0; j < n_ress; ++j) {
- ir_node *proj = ress[j];
- ir_node *proj_proj;
- ir_node *irn;
-
- if (get_irn_op(proj) != op_Proj) {
- /* not routed to a call */
- break;
- }
-
- proj_proj = get_Proj_pred(proj);
-
- if (get_irn_op(proj) != op_Proj) {
- /* not routed to a call */
- break;
- }
-
- irn = get_Proj_pred(proj_proj);
-
- if (irn != call) {
- /* not routed to a call */
- break;
- }
- }
- if (j < n_ress)
- continue;
-
- /* here, we have found a call */
- set_irn_link(call, get_irn_link(end_block));
- set_irn_link(end_block, call);
- ++n_tail_calls;
-
- /* link all returns, we will need this */
- set_irn_link(ret, rets);
- rets = ret;
- }
-
- /* now, end_block->link contains the list of all tail calls */
- if (! n_tail_calls)
- return;
-
- do_opt_tail_rec(irg, rets, n_tail_calls);
+int opt_tail_rec_irg(ir_graph *irg) {
+ tr_env env;
+ ir_node *end_block;
+ int i, n_ress, n_tail_calls = 0;
+ ir_node *rets = NULL;
+ ir_type *mtd_type, *call_type;
+ ir_entity *ent;
+
+ assure_irg_outs(irg);
+
+ if (! check_lifetime_of_locals(irg))
+ return 0;
+
+
+ ent = get_irg_entity(irg);
+ mtd_type = get_entity_type(ent);
+ n_ress = get_method_n_ress(mtd_type);
+
+ env.variants = NULL;
+ env.n_ress = n_ress;
+
+ if (n_ress > 0) {
+ NEW_ARR_A(tail_rec_variants, env.variants, n_ress);
+
+ for (i = 0; i < n_ress; ++i)
+ env.variants[i] = TR_DIRECT;
+ }
+
+ /*
+ * This tail recursion optimization works best
+ * if the Returns are normalized.
+ */
+ normalize_n_returns(irg);
+
+ end_block = get_irg_end_block(irg);
+ set_irn_link(end_block, NULL);
+
+ for (i = get_Block_n_cfgpreds(end_block) - 1; i >= 0; --i) {
+ ir_node *ret = get_Block_cfgpred(end_block, i);
+ ir_node *call, *call_ptr;
+ int j;
+ ir_node **ress;
+
+ /* search all Returns of a block */
+ if (! is_Return(ret))
+ continue;
+
+ /* check, if it's a Return self() */
+ call = skip_Proj(get_Return_mem(ret));
+ if (! is_Call(call))
+ continue;
+
+ /* the call must be in the same block as the return */
+ if (get_nodes_block(call) != get_nodes_block(ret))
+ continue;
+
+ /* check if it's a recursive call */
+ call_ptr = get_Call_ptr(call);
+
+ if (! is_Global(call_ptr))
+ continue;
+
+ ent = get_Global_entity(call_ptr);
+ if (!ent || get_entity_irg(ent) != irg)
+ continue;
+
+ /*
+ * Check, that the types match. At least in C
+ * this might fail.
+ */
+ mtd_type = get_entity_type(ent);
+ call_type = get_Call_type(call);
+
+ if (mtd_type != call_type) {
+ /*
+ * Hmm, the types did not match, bad.
+ * This can happen in C when no prototype is given
+ * or K&R style is used.
+ */
+#if 0
+ printf("Warning: Tail recursion fails because of different method and call types:\n");
+ dump_type(mtd_type);
+ dump_type(call_type);
+#endif
+ continue;
+ }
+
+ /* ok, mem is routed to a recursive call, check return args */
+ ress = get_Return_res_arr(ret);
+ for (j = get_Return_n_ress(ret) - 1; j >= 0; --j) {
+ tail_rec_variants var = find_variant(ress[j], call);
+
+ if (var >= TR_BAD) {
+ /* cannot be transformed */
+ break;
+ }
+ if (var == TR_DIRECT)
+ var = env.variants[j];
+ else if (env.variants[j] == TR_DIRECT)
+ env.variants[j] = var;
+ if (env.variants[j] != var) {
+ /* not compatible */
+ break;
+ }
+ }
+ if (j >= 0)
+ continue;
+
+ /* here, we have found a call */
+ set_irn_link(call, get_irn_link(end_block));
+ set_irn_link(end_block, call);
+ ++n_tail_calls;
+
+ /* link all returns, we will need this */
+ set_irn_link(ret, rets);
+ rets = ret;
+ }
+
+ /* now, end_block->link contains the list of all tail calls */
+ if (n_tail_calls <= 0)
+ return 0;
+
+ DB((dbg, LEVEL_2, " Performing tail recursion for graph %s and %d Calls\n",
+ get_entity_ld_name(get_irg_entity(irg)), n_tail_calls));
+
+ hook_tail_rec(irg, n_tail_calls);
+
+ env.n_tail_calls = n_tail_calls;
+ env.rets = rets;
+ do_opt_tail_rec(irg, &env);
+
+ return n_tail_calls;
}
/*
* optimize tail recursion away
*/
-void opt_tail_recursion(void)
-{
- int i;
+void opt_tail_recursion(void) {
+ int i;
+ int n_opt_applications = 0;
+ ir_graph *irg;
- if (! get_opt_tail_recursion() || ! get_opt_optimize())
- return;
+ FIRM_DBG_REGISTER(dbg, "firm.opt.tailrec");
- for (i = 0; i < get_irp_n_irgs(); i++) {
- current_ir_graph = get_irp_irg(i);
+ for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
+ irg = get_irp_irg(i);
+
+ current_ir_graph = irg;
+
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+ if (opt_tail_rec_irg(irg))
+ ++n_opt_applications;
+
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+ }
- opt_tail_rec_irg(current_ir_graph);
- }
+ DB((dbg, LEVEL_1, "Performed tail recursion for %d of %d graphs\n",
+ n_opt_applications, get_irp_n_irgs()));
}
projects / libfirm / blobdiff