X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Ftailrec.c;h=c64759ff57cb153690362a8dcc50b64b3969720c;hb=0fbcef83aa6060534172bb13e71cdadb04428806;hp=b0402da9d39cb9d12f5e4d15926df9c4c1a69d47;hpb=1ec30d95387eb392ba5a1adc7958ebd91383d59c;p=libfirm

diff --git a/ir/opt/tailrec.c b/ir/opt/tailrec.c
index b0402da9d..c64759ff5 100644
--- a/ir/opt/tailrec.c
+++ b/ir/opt/tailrec.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
@@ -24,16 +24,15 @@
  * @author  Michael Beck
  * @version $Id$
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include "config.h"
 
 #include <string.h>
 #include <assert.h>
 
+#include "debug.h"
 #include "iroptimize.h"
 #include "scalar_replace.h"
-#include "array.h"
+#include "array_t.h"
 #include "irprog_t.h"
 #include "irgwalk.h"
 #include "irgmod.h"
@@ -45,7 +44,9 @@
 #include "trouts.h"
 #include "irouts.h"
 #include "irhooks.h"
-#include "xmalloc.h"
+#include "ircons_t.h"
+
+DEBUG_ONLY(static firm_dbg_module_t *dbg);
 
 /**
  * the environment for collecting data
@@ -74,7 +75,7 @@ static void collect_data(ir_node *node, void *env) {
 		if (op == op_Proj) {
 			ir_node *start = get_Proj_pred(pred);
 
-			if (get_irn_op(start) == op_Start) {
+			if (is_Start(start)) {
 				if (get_Proj_proj(pred) == pn_Start_T_args) {
 					/* found Proj(ProjT(Start)) */
 					set_irn_link(node, data->proj_data);
@@ -110,6 +111,22 @@ static void collect_data(ir_node *node, void *env) {
 	}
 }
 
+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
  *
@@ -117,20 +134,23 @@ static void collect_data(ir_node *node, void *env) {
  * @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) {
+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;
+	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(n_tail_calls);
+	assert(env->n_tail_calls > 0);
 
 	/* we add new nodes, so the outs are inconsistent */
 	set_irg_outs_inconsistent(irg);
@@ -166,26 +186,26 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 	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, n_tail_calls + 1);
+	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 = rets; p; p = n) {
+	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));
+		// exchange(p, new_r_Bad(irg));
 
 		/* we might generate an endless loop, so add
-		* the block to the keep-alive list */
+		 * 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, n_tail_calls + 1, in);
+	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 */
@@ -204,9 +224,9 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 		in[i] = get_Call_mem(calls);
 		++i;
 	}
-	assert(i == n_tail_calls + 1);
+	assert(i == env->n_tail_calls + 1);
 
-	phis[0] = new_r_Phi(irg, block, n_tail_calls + 1, in, mode_M);
+	phis[0] = new_r_Phi(irg, block, env->n_tail_calls + 1, in, mode_M);
 
 	/* build the data Phi's */
 	if (n_params > 0) {
@@ -214,7 +234,7 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 		ir_node *args;
 		ir_node *args_bl;
 
-		NEW_ARR_A(ir_node **, call_params, n_tail_calls);
+		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)) {
@@ -229,10 +249,10 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 			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 < n_tail_calls; ++j)
+			for (j = 0; j < env->n_tail_calls; ++j)
 				in[j + 1] = call_params[j][i];
 
-			phis[i + 1] = new_r_Phi(irg, block, n_tail_calls + 1, in, mode);
+			phis[i + 1] = new_r_Phi(irg, block, env->n_tail_calls + 1, in, mode);
 		}
 	}
 
@@ -240,10 +260,7 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 	 * 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 = n) {
-		n = get_irn_link(p);
-		exchange(p, phis[0]);
-	}
+	exchange(data.proj_m, phis[0]);
 	for (p = data.proj_data; p; p = n) {
 		long proj = get_Proj_proj(p);
 
@@ -261,6 +278,133 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
 	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;
+	}
+
+	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;
 }
 
 /**
@@ -273,36 +417,184 @@ static void do_opt_tail_rec(ir_graph *irg, ir_node *rets, int n_tail_calls) {
  * @return non-zero if it's ok to do tail recursion
  */
 static int check_lifetime_of_locals(ir_graph *irg) {
-	ir_node *irg_frame = get_irg_frame(irg);
+	ir_node *irg_frame, *irg_val_param_base;
 	int i;
 
-	if (get_irg_outs_state(irg) != outs_consistent)
-		compute_irg_outs(irg);
-
+	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
  */
 int opt_tail_rec_irg(ir_graph *irg) {
-	ir_node *end_block;
-	int i, n_tail_calls = 0;
-	ir_node *rets = NULL;
-	ir_type *mtd_type, *call_type;
+	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;
 
-	if (! get_opt_tail_recursion() || ! get_opt_optimize())
-		return 0;
+	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.
@@ -315,7 +607,6 @@ int opt_tail_rec_irg(ir_graph *irg) {
 	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;
-		ir_entity *ent;
 		int j;
 		ir_node **ress;
 
@@ -328,36 +619,24 @@ int opt_tail_rec_irg(ir_graph *irg) {
 		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 (get_irn_op(call_ptr) != op_SymConst)
-			continue;
-
-		if (get_SymConst_kind(call_ptr) != symconst_addr_ent)
+		if (! is_Global(call_ptr))
 			continue;
 
-		ent = get_SymConst_entity(call_ptr);
+		ent = get_Global_entity(call_ptr);
 		if (!ent || get_entity_irg(ent) != irg)
 			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) {
-			ir_node *irn = skip_Proj(skip_Proj(ress[j]));
-
-			if (irn != call) {
-				/* not routed to a call */
-				break;
-			}
-		}
-		if (j >= 0)
-			continue;
-
 		/*
-		* Check, that the types match. At least in C
-		* this might fail.
-		*/
+		 * Check, that the types match. At least in C
+		 * this might fail.
+		 */
 		mtd_type  = get_entity_type(ent);
 		call_type = get_Call_type(call);
 
@@ -372,8 +651,29 @@ int opt_tail_rec_irg(ir_graph *irg) {
 			dump_type(mtd_type);
 			dump_type(call_type);
 #endif
-			return 0;
+			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));
@@ -386,15 +686,17 @@ int opt_tail_rec_irg(ir_graph *irg) {
 	}
 
 	/* now, end_block->link contains the list of all tail calls */
-	if (! n_tail_calls)
+	if (n_tail_calls <= 0)
 		return 0;
 
-	if (get_opt_tail_recursion_verbose() && get_firm_verbosity() > 1)
-		printf("  Performing tail recursion for graph %s and %d Calls\n",
-		get_entity_ld_name(get_irg_entity(irg)), n_tail_calls);
+	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);
-	do_opt_tail_rec(irg, rets, n_tail_calls);
+
+	env.n_tail_calls = n_tail_calls;
+	env.rets         = rets;
+	do_opt_tail_rec(irg, &env);
 
 	return n_tail_calls;
 }
@@ -407,16 +709,20 @@ void opt_tail_recursion(void) {
 	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 = 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);
 	}
 
-	if (get_opt_tail_recursion_verbose())
-		printf("Performed tail recursion for %d of %d graphs\n", n_opt_applications, get_irp_n_irgs());
+	DB((dbg, LEVEL_1, "Performed tail recursion for %d of %d graphs\n",
+	    n_opt_applications, get_irp_n_irgs()));
 }