/*
- * 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.
*
/* 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));
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
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.
*/
/**
* 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);
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))
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]);
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
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);
{
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);
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) {
}
del_waitq(env.wq);
+ current_ir_graph = rem;
} /* optimize_reassociation */
/* Sets the default reassociation operation for an ir_op_ops. */
CASE(And);
CASE(Or);
CASE(Eor);
+ CASE(Shl);
default:
/* leave NULL */;
}
projects / libfirm / blobdiff