X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Freassoc.c;h=8cfcd8c2ecfed349f15eb90771454c6c2b84fe34;hb=5ea724df1266e369e815c99d861dcbbe102acb11;hp=8d2985305c11723083cb1aa84b96facd14fee5e9;hpb=14c2b23979f197bd409c9030ca740b786ea13bfc;p=libfirm

diff --git a/ir/opt/reassoc.c b/ir/opt/reassoc.c
index 8d2985305..8cfcd8c2e 100644
--- a/ir/opt/reassoc.c
+++ b/ir/opt/reassoc.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.
  *
@@ -168,12 +168,13 @@ static int reassoc_Sub(ir_node **in)
 			/* already constant, nothing to do */
 			return 0;
 		}
+
 		mode = get_irn_mode(n);
 		dbi  = get_irn_dbg_info(n);
 
 		/* Beware of SubP(P, Is) */
 		irn = new_rd_Minus(dbi, current_ir_graph, block, right, rmode);
-		irn = new_rd_Add(dbi, current_ir_graph, block, left, irn, get_irn_mode(n));
+		irn = new_rd_Add(dbi, current_ir_graph, block, left, irn, mode);
 
 		DBG((dbg, LEVEL_5, "Applied: %n - %n => %n + (-%n)\n",
 			get_Sub_left(n), right, get_Sub_left(n), right));
@@ -338,7 +339,6 @@ static int reassoc_Mul(ir_node **node)
 			in[0] = new_rd_Mul(NULL, current_ir_graph, block, c, t1, mode);
 			in[1] = new_rd_Mul(NULL, current_ir_graph, block, c, t2, mode);
 
-			mode  = get_mode_from_ops(in[0], in[1]);
 			irn   = optimize_node(new_ir_node(NULL, current_ir_graph, block, op, mode, 2, in));
 
 			/* In some cases it might happen that the new irn is equal the old one, for
@@ -363,6 +363,40 @@ static int reassoc_Mul(ir_node **node)
 	return 0;
 }  /* reassoc_Mul */
 
+/**
+ * Reassociate Shl. We transform Shl(x, const) into Mul's if possible.
+ */
+static int reassoc_Shl(ir_node **node) {
+	ir_node *n = *node;
+	ir_node *c = get_Shl_right(n);
+	ir_node *x, *blk, *irn;
+	ir_mode *mode;
+	tarval *tv;
+
+	if (! is_Const(c))
+		return 0;
+
+	x = get_Shl_left(n);
+	mode = get_irn_mode(x);
+
+	tv = get_mode_one(mode);
+	tv = tarval_shl(tv, get_Const_tarval(c));
+
+	if (tv == tarval_bad)
+		return 0;
+
+	blk = get_nodes_block(n);
+	c   = new_r_Const(current_ir_graph, blk, mode, tv);
+	irn = new_rd_Mul(get_irn_dbg_info(n), current_ir_graph, blk, x, c, mode);
+
+	if (irn != n) {
+		exchange(n, irn);
+		*node = irn;
+		return 1;
+	}
+	return 0;
+}  /* reassoc_Shl */
+
 /**
  * The walker for the reassociation.
  */
@@ -446,61 +480,190 @@ static void do_reassociation(walker_t *wenv)
 
 /**
  * Returns the earliest were a,b are available.
- * Note that we know that we know that a, b both dominate
+ * Note that we know that a, b both dominate
  * the block of the previous operation, so one must dominate the other.
+ *
+ * If the earliest block is the start block, return curr_blk instead
  */
-static ir_node *earliest_block(ir_node *a, ir_node *b) {
+static ir_node *earliest_block(ir_node *a, ir_node *b, ir_node *curr_blk) {
 	ir_node *blk_a = get_nodes_block(a);
 	ir_node *blk_b = get_nodes_block(b);
+	ir_node *res;
 
 	/* if blk_a != blk_b, one must dominate the other */
 	if (block_dominates(blk_a, blk_b))
-		return blk_b;
+		res = blk_b;
 	else
-		return blk_a;
-}
+		res = blk_a;
+	if (res == get_irg_start_block(current_ir_graph))
+		return curr_blk;
+	return res;
+}  /* earliest_block */
+
+/**
+ * Checks whether a node is a Constant expression.
+ * The following trees are constant expressions:
+ *
+ * Const, SymConst, Const + SymConst
+ *
+ * Handling SymConsts as const might be not a good idea for all
+ * architectures ...
+ */
+static int is_constant_expr(ir_node *irn) {
+	ir_op *op;
 
+	switch (get_irn_opcode(irn)) {
+	case iro_Const:
+	case iro_SymConst:
+		return 1;
+	case iro_Add:
+		op = get_irn_op(get_Add_left(irn));
+		if (op != op_Const && op != op_SymConst)
+			return 0;
+		op = get_irn_op(get_Add_right(irn));
+		if (op != op_Const && op != op_SymConst)
+			return 0;
+		return 1;
+	default:
+		return 0;
+	}
+}  /* is_constant_expr */
+
+/**
+ * Apply distributive Law for Mul and Add/Sub
+ */
+static int reverse_rule_distributive(ir_node **node) {
+	ir_node *n = *node;
+	ir_node *left  = get_binop_left(n);
+	ir_node *right = get_binop_right(n);
+	ir_node *x, *blk, *curr_blk;
+	ir_node *a, *b, *irn;
+	ir_op *op;
+	ir_mode *mode;
+	dbg_info *dbg;
+
+	op = get_irn_op(left);
+	if (op != get_irn_op(right))
+		return 0;
+
+	if (op == op_Shl) {
+		x = get_Shl_right(left);
+
+		if (x == get_Shl_right(right)) {
+			/* (a << x) +/- (b << x) ==> (a +/- b) << x */
+			a = get_Shl_left(left);
+			b = get_Shl_left(right);
+			goto transform;
+		}
+	} else if (op == op_Mul) {
+		x = get_Mul_left(left);
+
+		if (x == get_Mul_left(right)) {
+			/* (x * a) +/- (x * b) ==> (a +/- b) * x */
+			a = get_Mul_right(left);
+			b = get_Mul_right(right);
+			goto transform;
+		} else if (x == get_Mul_right(right)) {
+			/* (x * a) +/- (b * x) ==> (a +/- b) * x */
+			a = get_Mul_right(left);
+			b = get_Mul_left(right);
+			goto transform;
+		}
+
+		x = get_Mul_right(left);
+
+		if (x == get_Mul_right(right)) {
+			/* (a * x) +/- (b * x) ==> (a +/- b) * x */
+			a = get_Mul_left(left);
+			b = get_Mul_left(right);
+			goto transform;
+		} else if (x == get_Mul_left(right)) {
+			/* (a * x) +/- (x * b) ==> (a +/- b) * x */
+			a = get_Mul_left(left);
+			b = get_Mul_right(right);
+			goto transform;
+		}
+	}
+	return 0;
+
+transform:
+	curr_blk = get_nodes_block(n);
+
+	blk = earliest_block(a, b, curr_blk);
+
+	dbg  = get_irn_dbg_info(n);
+	mode = get_irn_mode(n);
+
+	if (is_Add(n))
+		irn = new_rd_Add(dbg, current_ir_graph, blk, a, b, mode);
+	else
+		irn = new_rd_Sub(dbg, current_ir_graph, blk, a, b, mode);
+
+	blk  = earliest_block(irn, x, curr_blk);
+
+	if (op == op_Mul)
+		irn = new_rd_Mul(dbg, current_ir_graph, blk, irn, x, mode);
+	else
+		irn = new_rd_Shl(dbg, current_ir_graph, blk, irn, x, mode);
+
+	exchange(n, irn);
+	*node = irn;
+	return 1;
+}  /* reverse_rule_distributive */
 
 /**
  * Move Constants towards the root.
  */
 static int move_consts_up(ir_node **node) {
 	ir_node *n = *node;
-	ir_op *op = get_irn_op(n);
+	ir_op *op;
 	ir_node *l, *r, *a, *b, *c, *blk, *irn, *in[2];
-	ir_mode *mode;
-	dbg_info *dbg = get_irn_dbg_info(n);
+	ir_mode *mode, *ma, *mb;
+	dbg_info *dbg;
 
 	l = get_binop_left(n);
 	r = get_binop_right(n);
-	if (get_irn_op(l) == op && !is_irn_constlike(r)) {
+
+	/* check if one is already a constant expression */
+	if (is_constant_expr(l) || is_constant_expr(r))
+		return 0;
+
+	dbg = get_irn_dbg_info(n);
+	op = get_irn_op(n);
+	if (get_irn_op(l) == op) {
+		/* (a .op. b) .op. r */
 		a = get_binop_left(l);
 		b = get_binop_right(l);
 
-		if (is_irn_constlike(a)) {
+		if (is_constant_expr(a)) {
+			/* (C .op. b) .op. r ==> (r .op. b) .op. C */
 			c = a;
 			a = r;
 			blk = get_nodes_block(l);
 			dbg = dbg == get_irn_dbg_info(l) ? dbg : NULL;
 			goto transform;
-		} else if (is_irn_constlike(b)) {
+		} else if (is_constant_expr(b)) {
+			/* (a .op. C) .op. r ==> (a .op. r) .op. C */
 			c = b;
 			b = r;
 			blk = get_nodes_block(l);
 			dbg = dbg == get_irn_dbg_info(l) ? dbg : NULL;
 			goto transform;
 		}
-	} else if (get_irn_op(r) == op && !is_irn_constlike(l)) {
+	} else if (get_irn_op(r) == op) {
+		/* l .op. (a .op. b) */
 		a = get_binop_left(r);
 		b = get_binop_right(r);
 
-		if (is_irn_constlike(a)) {
+		if (is_constant_expr(a)) {
+			/* l .op. (C .op. b) ==> (l .op. b) .op. C */
 			c = a;
 			a = l;
 			blk = get_nodes_block(r);
 			dbg = dbg == get_irn_dbg_info(r) ? dbg : NULL;
 			goto transform;
-		} else if (is_irn_constlike(b)) {
+		} else if (is_constant_expr(b)) {
+			/* l .op. (a .op. C) ==> (a .op. l) .op. C */
 			c = b;
 			b = l;
 			blk = get_nodes_block(r);
@@ -511,7 +674,18 @@ static int move_consts_up(ir_node **node) {
 	return 0;
 
 transform:
-	/* check if a+b can be calculted in the same block is the old instruction */
+	/* In some cases a and b might be both of different integer mode, and c a SymConst.
+	 * in that case we could either
+	 * 1.) cast into unsigned mode
+	 * 2.) ignore
+	 * we implement the second here
+	 */
+	ma = get_irn_mode(a);
+	mb = get_irn_mode(b);
+	if (ma != mb && mode_is_int(ma) && mode_is_int(mb))
+		return 0;
+
+	/* check if (a .op. b) can be calculated in the same block is the old instruction */
 	if (! block_dominates(get_nodes_block(a), blk))
 		return 0;
 	if (! block_dominates(get_nodes_block(b), blk))
@@ -520,8 +694,13 @@ transform:
 	in[0] = a;
 	in[1] = b;
 
-	mode = get_mode_from_ops(in[0], in[1]);
-	in[0] = optimize_node(new_ir_node(dbg, current_ir_graph, blk, op, mode, 2, in));
+	mode = get_mode_from_ops(a, b);
+	in[0] = irn = optimize_node(new_ir_node(dbg, current_ir_graph, blk, op, mode, 2, in));
+
+	/* beware: optimize_node might have changed the opcode, check again */
+	if (is_Add(irn) || is_Sub(irn)) {
+		reverse_rule_distributive(&in[0]);
+	}
 	in[1] = c;
 
 	mode = get_mode_from_ops(in[0], in[1]);
@@ -530,70 +709,7 @@ transform:
 	exchange(n, irn);
 	*node = irn;
 	return 1;
-}  /* mve_consts_up */
-
-/**
- * Apply distributive Law for Mul and Add/Sub
- */
-static int reverse_rule_distributive(ir_node **node) {
-	ir_node *n = *node;
-	ir_node *left  = get_binop_left(n);
-	ir_node *right = get_binop_right(n);
-	ir_node *x, *blk;
-	ir_node *a, *b, *irn;
-	ir_mode *mode;
-	dbg_info *dbg;
-
-	if (! is_Mul(left) || !is_Mul(right))
-		return 0;
-
-	x = get_Mul_left(left);
-
-	if (x == get_Mul_left(right)) {
-		/* (x * a) +/- (x * b) */
-		a = get_Mul_right(left);
-		b = get_Mul_right(right);
-		goto transform;
-	} else if (x == get_Mul_right(right)) {
-		/* (x * a) +/- (b * x) */
-		a = get_Mul_right(left);
-		b = get_Mul_left(right);
-		goto transform;
-	}
-
-	x = get_Mul_right(left);
-
-	if (x == get_Mul_right(right)) {
-		/* (a * x) +/- (b * x) */
-		a = get_Mul_left(left);
-		b = get_Mul_left(right);
-		goto transform;
-	} else if (x == get_Mul_left(right)) {
-		/* (a * x) +/- (x * b) */
-		a = get_Mul_left(left);
-		b = get_Mul_right(right);
-		goto transform;
-	}
-	return 0;
-
-transform:
-	blk = earliest_block(a, b);
-
-	dbg  = get_irn_dbg_info(n);
-	mode = get_irn_mode(n);
-
-	if (is_Add(n))
-		irn = new_rd_Add(dbg, current_ir_graph, blk, a, b, mode);
-	else
-		irn = new_rd_Sub(dbg, current_ir_graph, blk, a, b, mode);
-
-	blk  = earliest_block(irn, x);
-	irn = new_rd_Mul(dbg, current_ir_graph, blk, irn, x, mode);
-
-	exchange(n, irn);
-	*node = irn;
-	return 1;
-}  /* reverse_rule_distributive */
+}  /* move_consts_up */
 
 /**
  * Apply the rules in reverse order, removing code that was not collapsed
@@ -612,10 +728,10 @@ static void reverse_rules(ir_node *node, void *env) {
 
 		res = 0;
 		if (is_op_commutative(op)) {
-			/* no need to recurse here */
-			wenv->changes |= move_consts_up(&node);
+			wenv->changes |= res = move_consts_up(&node);
 		}
-		if (op == op_Add || op == op_Sub) {
+		/* beware: move_consts_up might have changed the opcode, check again */
+		if (is_Add(node) || is_Sub(node)) {
 			wenv->changes |= res = reverse_rule_distributive(&node);
 		}
 	} while (res);
@@ -628,14 +744,14 @@ void optimize_reassociation(ir_graph *irg)
 {
 	walker_t env;
 	irg_loopinfo_state state;
+	ir_graph *rem;
 
 	assert(get_irg_phase_state(irg) != phase_building);
 	assert(get_irg_pinned(irg) != op_pin_state_floats &&
 		"Reassociation needs pinned graph to work properly");
 
-	/* reassociation needs constant folding */
-	if (!get_opt_reassociation() || !get_opt_constant_folding())
-		return;
+	rem = current_ir_graph;
+	current_ir_graph = irg;
 
 	/* we use dominance to detect dead blocks */
 	assure_doms(irg);
@@ -654,12 +770,17 @@ void optimize_reassociation(ir_graph *irg)
 	env.changes = 0;
 	env.wq      = new_waitq();
 
-	/* now we have collected enough information, optimize */
-	irg_walk_graph(irg, NULL, wq_walker, &env);
-	do_reassociation(&env);
+	/* disable some optimizations while reassoc is running to prevent endless loops */
+	set_reassoc_running(1);
+	{
+		/* now we have collected enough information, optimize */
+		irg_walk_graph(irg, NULL, wq_walker, &env);
+		do_reassociation(&env);
 
-	/* reverse those rules that do not result in collapsed constants */
-	irg_walk_graph(irg, NULL, reverse_rules, &env);
+		/* reverse those rules that do not result in collapsed constants */
+		irg_walk_graph(irg, NULL, reverse_rules, &env);
+	}
+	set_reassoc_running(0);
 
 	/* Handle graph state */
 	if (env.changes) {
@@ -668,6 +789,7 @@ void optimize_reassociation(ir_graph *irg)
 	}
 
 	del_waitq(env.wq);
+	current_ir_graph = rem;
 }  /* optimize_reassociation */
 
 /* Sets the default reassociation operation for an ir_op_ops. */
@@ -682,6 +804,7 @@ ir_op_ops *firm_set_default_reassoc(ir_opcode code, ir_op_ops *ops)
 	CASE(And);
 	CASE(Or);
 	CASE(Eor);
+	CASE(Shl);
 	default:
 		/* leave NULL */;
 	}