/*
- * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
+ * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
return new_rd_ASM(NULL, block, arity, in, inputs, n_outs, outputs, n_clobber, clobber, text);
}
-/* ***********************************************************************/
-/* Methods necessary for automatic Phi node creation */
-/*
- ir_node *phi_merge (ir_node *block, int pos, ir_mode *mode, ir_node **nin, int ins)
- ir_node *get_r_value_internal (ir_node *block, int pos, ir_mode *mode);
- ir_node *new_rd_Phi0 (ir_graph *irg, ir_node *block, ir_mode *mode)
- ir_node *new_rd_Phi_in (ir_graph *irg, ir_node *block, ir_mode *mode, ir_node **in, int ins)
-
- Call Graph: ( A ---> B == A "calls" B)
-
- get_value mature_immBlock
- | |
- | |
- | |
- | ---> phi_merge
- | / / \
- | / / \
- \|/ / |/_ \
- get_r_value_internal |
- | |
- | |
- \|/ \|/
- new_rd_Phi0 new_rd_Phi_in
-
-* *************************************************************************** */
-
/** Creates a Phi node with 0 predecessors. */
-static inline ir_node *new_rd_Phi0(ir_node *block, ir_mode *mode)
+static inline ir_node *new_rd_Phi0(dbg_info *dbgi, ir_node *block,
+ ir_mode *mode, int pos)
{
ir_graph *irg = get_irn_irg(block);
- ir_node *res = new_ir_node(NULL, irg, block, op_Phi, mode, 0, NULL);
+ ir_node *res = new_ir_node(dbgi, irg, block, op_Phi, mode, 0, NULL);
+ res->attr.phi.u.pos = pos;
irn_verify_irg(res, irg);
return res;
}
-/**
- * Internal constructor of a Phi node by a phi_merge operation.
- *
- * @param block the block in which the Phi will be constructed
- * @param mode the mod eof the Phi node
- * @param in the input array of the phi node
- * @param n_in number of elements in the input array
- * @param phi0 in non-NULL: the Phi0 node in the same block that represents
- * the value for which the new Phi is constructed
- */
-static ir_node *new_rd_Phi_in(ir_node *block, ir_mode *mode,
- int n_in, ir_node **in, ir_node *phi0)
-{
- int i;
- ir_node *res, *known;
- ir_graph *irg = get_irn_irg(block);
-
- /* Allocate a new node on the obstack. The allocation copies the in
- array. */
- res = new_ir_node(NULL, irg, block, op_Phi, mode, n_in, in);
- res->attr.phi.u.backedge = new_backedge_arr(irg->obst, n_in);
-
- /* This loop checks whether the Phi has more than one predecessor.
- If so, it is a real Phi node and we break the loop. Else the
- Phi node merges the same definition on several paths and therefore
- is not needed.
- Note: We MUST consider Bad nodes, else we might get data flow cycles in dead loops! */
- known = res;
- for (i = n_in - 1; i >= 0; --i) {
- assert(in[i]);
-
- in[i] = skip_Id(in[i]); /* increases the number of freed Phis. */
+static ir_node *get_r_value_internal(ir_node *block, int pos, ir_mode *mode);
- /* Optimize self referencing Phis: We can't detect them yet properly, as
- they still refer to the Phi0 they will replace. So replace right now. */
- if (phi0 && in[i] == phi0)
- in[i] = res;
+static void try_remove_unnecessary_phi(ir_node *phi)
+{
+ ir_node *phi_value = NULL;
+ int arity = get_irn_arity(phi);
+ int i;
- if (in[i] == res || in[i] == known)
+ /* see if all inputs are either pointing to a single value or
+ * are self references */
+ for (i = 0; i < arity; ++i) {
+ ir_node *in = get_irn_n(phi, i);
+ if (in == phi)
continue;
-
- if (known == res)
- known = in[i];
- else
- break;
+ if (in == phi_value)
+ continue;
+ /** found a different value from the one we already found, can't remove
+ * the phi (yet) */
+ if (phi_value != NULL)
+ return;
+ phi_value = in;
}
+ if (phi_value == NULL)
+ return;
- /* i < 0: there is at most one predecessor, we don't need a phi node. */
- if (i < 0) {
- if (res != known) {
- edges_node_deleted(res, irg);
- obstack_free(irg->obst, res);
- if (is_Phi(known)) {
- /* If pred is a phi node we want to optimize it: If loops are matured in a bad
- order, an enclosing Phi know may get superfluous. */
- res = optimize_in_place_2(known);
- if (res != known)
- exchange(known, res);
- }
- else
- res = known;
- } else {
- /* A undefined value, e.g., in unreachable code. */
- res = new_r_Bad(irg);
- }
- } else {
- res = optimize_node(res); /* This is necessary to add the node to the hash table for cse. */
- irn_verify_irg(res, irg);
- /* Memory Phis in endless loops must be kept alive.
- As we can't distinguish these easily we keep all of them alive. */
- if (is_Phi(res) && mode == mode_M)
- add_End_keepalive(get_irg_end(irg), res);
- }
+ /* if we're here then all phi inputs have been either phi_value
+ * or self-references, we can replace the phi by phi_value.
+ * We do this with an Id-node */
+ exchange(phi, phi_value);
- return res;
+ /* recursively check phi_value, because it could be that we were the last
+ * phi-node in a loop-body. Then our arguments is an unnecessary phi in
+ * the loop header which can be eliminated now */
+ if (is_Phi(phi_value)) {
+ try_remove_unnecessary_phi(phi_value);
+ }
}
-static ir_node *get_r_value_internal(ir_node *block, int pos, ir_mode *mode);
-
/**
* Computes the predecessors for the real phi node, and then
* allocates and returns this node. The routine called to allocate the
* node might optimize it away and return a real value.
* This function must be called with an in-array of proper size.
*/
-static ir_node *phi_merge(ir_node *block, int pos, ir_mode *mode,
- int n_ins, ir_node **ins)
+static ir_node *set_phi_arguments(ir_node *phi, int pos)
{
- ir_graph *irg = get_irn_irg(block);
- ir_node *prevBlock, *res, *phi0, *phi0_all;
- int i;
-
- /* If this block has no value at pos create a Phi0 and remember it
- in graph_arr to break recursions.
- Else we may not set graph_arr as there a later value is remembered. */
- phi0 = NULL;
- if (block->attr.block.graph_arr[pos] == NULL) {
-
- if (block == get_irg_start_block(irg)) {
- /* Collapsing to Bad tarvals is no good idea.
- So we call a user-supplied routine here that deals with this
- case as appropriate for the given language. Sorrily the only
- help we can give here is the position.
-
- Even if all variables are defined before use, it can happen that
- we get to the start block, if a Cond has been replaced by a tuple
- (bad, jmp). In this case we call the function needlessly,
- eventually generating an non existent error.
- However, this SHOULD NOT HAPPEN, as bad control flow nodes are
- intercepted before recurring.
- */
- if (default_initialize_local_variable != NULL) {
- ir_node *rem = get_r_cur_block(irg);
-
- set_r_cur_block(irg, block);
- block->attr.block.graph_arr[pos] = default_initialize_local_variable(irg, mode, pos - 1);
- set_r_cur_block(irg, rem);
- } else {
- block->attr.block.graph_arr[pos] = new_r_Unknown(irg, mode);
- }
- return block->attr.block.graph_arr[pos];
- } else {
- phi0 = new_rd_Phi0(block, mode);
- block->attr.block.graph_arr[pos] = phi0;
- }
- }
+ ir_node *block = get_nodes_block(phi);
+ ir_graph *irg = get_irn_irg(block);
+ int arity = get_irn_arity(block);
+ ir_node **in = ALLOCAN(ir_node*, arity);
+ ir_mode *mode = get_irn_mode(phi);
+ int i;
/* This loop goes to all predecessor blocks of the block the Phi node
is in and there finds the operands of the Phi node by calling
get_r_value_internal. */
- for (i = 1; i <= n_ins; ++i) {
- ir_node *cf_pred = block->in[i];
- ir_node *prevCfOp = skip_Proj(cf_pred);
- assert(prevCfOp);
- if (is_Bad(prevCfOp)) {
- /* In case a Cond has been optimized we would get right to the start block
- with an invalid definition. */
- ins[i-1] = new_r_Bad(irg);
- continue;
- }
- prevBlock = prevCfOp->in[0]; /* go past control flow op to prev block */
- assert(prevBlock);
- if (!is_Bad(prevBlock)) {
- ins[i-1] = get_r_value_internal(prevBlock, pos, mode);
+ for (i = 0; i < arity; ++i) {
+ ir_node *cfgpred = get_Block_cfgpred_block(block, i);
+ ir_node *value;
+ if (is_Bad(cfgpred)) {
+ value = new_r_Bad(irg);
} else {
- ins[i-1] = new_r_Bad(irg);
+ value = get_r_value_internal(cfgpred, pos, mode);
}
+ in[i] = value;
}
- /* We want to pass the Phi0 node to the constructor: this finds additional
- optimization possibilities.
- The Phi0 node either is allocated in this function, or it comes from
- a former call to get_r_value_internal(). In this case we may not yet
- exchange phi0, as this is done in mature_immBlock(). */
- if (phi0 == NULL) {
- phi0_all = block->attr.block.graph_arr[pos];
- if (! is_Phi0(phi0_all) ||
- get_irn_arity(phi0_all) != 0 ||
- get_nodes_block(phi0_all) != block)
- phi0_all = NULL;
- } else {
- phi0_all = phi0;
- }
+ phi->attr.phi.u.backedge = new_backedge_arr(irg->obst, arity);
+ set_irn_in(phi, arity, in);
+ set_irn_op(phi, op_Phi);
- /* After collecting all predecessors into the array ins a new Phi node
- with these predecessors is created. This constructor contains an
- optimization: If all predecessors of the Phi node are identical it
- returns the only operand instead of a new Phi node. */
- res = new_rd_Phi_in(block, mode, n_ins, ins, phi0_all);
-
- /* In case we allocated a Phi0 node at the beginning of this procedure,
- we need to exchange this Phi0 with the real Phi. */
- if (phi0 != NULL) {
- exchange(phi0, res);
- block->attr.block.graph_arr[pos] = res;
- }
+ irn_verify_irg(phi, irg);
- return res;
+ /* Memory Phis in endless loops must be kept alive.
+ As we can't distinguish these easily we keep all of them alive. */
+ if (is_Phi(phi) && mode == mode_M)
+ add_End_keepalive(get_irg_end(irg), phi);
+
+ try_remove_unnecessary_phi(phi);
+ return phi;
}
/**
*/
static ir_node *get_r_value_internal(ir_node *block, int pos, ir_mode *mode)
{
- ir_node *res;
- /* There are 4 cases to treat.
-
- 1. The block is not mature and we visit it the first time. We can not
- create a proper Phi node, therefore a Phi0, i.e., a Phi without
- predecessors is returned. This node is added to the linked list (block
- attribute "phis") of the containing block to be completed when this block is
- matured. (Completion will add a new Phi and turn the Phi0 into an Id
- node.)
-
- 2. The value is already known in this block, graph_arr[pos] is set and we
- visit the block the first time. We can return the value without
- creating any new nodes.
-
- 3. The block is mature and we visit it the first time. A Phi node needs
- to be created (phi_merge). If the Phi is not needed, as all it's
- operands are the same value reaching the block through different
- paths, it's optimized away and the value itself is returned.
-
- 4. The block is mature, and we visit it the second time. Now two
- subcases are possible:
- * The value was computed completely the last time we were here. This
- is the case if there is no loop. We can return the proper value.
- * The recursion that visited this node and set the flag did not
- return yet. We are computing a value in a loop and need to
- break the recursion. This case only happens if we visited
- the same block with phi_merge before, which inserted a Phi0.
- So we return the Phi0.
- */
-
- /* case 4 -- already visited. */
- if (irn_visited(block)) {
- /* As phi_merge allocates a Phi0 this value is always defined. Here
- is the critical difference of the two algorithms. */
- assert(block->attr.block.graph_arr[pos]);
- return block->attr.block.graph_arr[pos];
- }
-
- /* visited the first time */
- mark_irn_visited(block);
-
- /* Get the local valid value */
- res = block->attr.block.graph_arr[pos];
-
- /* case 2 -- If the value is actually computed, return it. */
+ ir_node *res = block->attr.block.graph_arr[pos];
if (res != NULL)
return res;
- if (block->attr.block.is_matured) { /* case 3 */
-
- /* The Phi has the same amount of ins as the corresponding block. */
- int n_in = get_irn_arity(block);
- ir_node **in;
- NEW_ARR_A(ir_node *, in, n_in);
-
- /* Phi merge collects the predecessors and then creates a node. */
- res = phi_merge(block, pos, mode, n_in, in);
- } else { /* case 1 */
- /* The block is not mature, we don't know how many in's are needed. A Phi
- with zero predecessors is created. Such a Phi node is called Phi0
- node. The Phi0 is then added to the list of Phi0 nodes in this block
- to be matured by mature_immBlock later.
- The Phi0 has to remember the pos of it's internal value. If the real
- Phi is computed, pos is used to update the array with the local
- values. */
- res = new_rd_Phi0(block, mode);
- res->attr.phi.u.pos = pos;
+ /* in a matured block we can immediately determine the phi arguments */
+ if (block->attr.block.is_matured) {
+ int arity = get_irn_arity(block);
+ /* no predecessors: use unknown value */
+ if (arity == 0 && block == get_irg_start_block(get_irn_irg(block))) {
+ ir_graph *irg = get_irn_irg(block);
+ if (default_initialize_local_variable != NULL) {
+ ir_node *rem = get_r_cur_block(irg);
+ set_r_cur_block(irg, block);
+ res = default_initialize_local_variable(irg, mode, pos - 1);
+ set_r_cur_block(irg, rem);
+ } else {
+ res = new_r_Unknown(irg, mode);
+ }
+ /* one predecessor just use its value */
+ } else if (arity == 1) {
+ ir_node *cfgpred = get_Block_cfgpred_block(block, 0);
+ if (is_Bad(cfgpred)) {
+ res = cfgpred;
+ } else {
+ res = get_r_value_internal(cfgpred, pos, mode);
+ }
+ /* multiple predecessors construct Phi */
+ } else {
+ res = new_rd_Phi0(NULL, block, mode, pos);
+ /* enter phi0 into our variable value table to break cycles
+ * arising from set_phi_arguments */
+ block->attr.block.graph_arr[pos] = res;
+ res = set_phi_arguments(res, pos);
+ }
+ } else {
+ /* in case of immature block we have to keep a Phi0 */
+ res = new_rd_Phi0(NULL, block, mode, pos);
+ /* enqueue phi so we can set arguments once the block matures */
res->attr.phi.next = block->attr.block.phis;
block->attr.block.phis = res;
}
-
- assert(is_ir_node(res) && "phi_merge() failed to construct a definition");
-
- /* The local valid value is available now. */
block->attr.block.graph_arr[pos] = res;
-
return res;
}
*/
void mature_immBlock(ir_node *block)
{
- int ins;
- ir_node *n, **nin;
- ir_node *next;
+ size_t n_preds;
+ ir_node *next;
+ ir_node *phi;
ir_graph *irg;
assert(is_Block(block));
if (get_Block_matured(block))
return;
- irg = get_irn_irg(block);
- ins = ARR_LEN(block->in) - 1;
+ irg = get_irn_irg(block);
+ n_preds = ARR_LEN(block->in) - 1;
/* Fix block parameters */
- block->attr.block.backedge = new_backedge_arr(irg->obst, ins);
-
- /* An array for building the Phi nodes. */
- NEW_ARR_A(ir_node *, nin, ins);
+ block->attr.block.backedge = new_backedge_arr(irg->obst, n_preds);
/* Traverse a chain of Phi nodes attached to this block and mature
these, too. */
- for (n = block->attr.block.phis; n; n = next) {
- inc_irg_visited(irg);
- next = n->attr.phi.next;
- exchange(n, phi_merge(block, n->attr.phi.u.pos, n->mode, ins, nin));
+ for (phi = block->attr.block.phis; phi != NULL; phi = next) {
+ ir_node *new_value;
+ int pos = phi->attr.phi.u.pos;
+
+ next = phi->attr.phi.next;
+ new_value = set_phi_arguments(phi, pos);
+ if (block->attr.block.graph_arr[pos] == phi) {
+ block->attr.block.graph_arr[pos] = new_value;
+ }
}
block->attr.block.is_matured = 1;
in[2] = irn_right;
res = new_ir_node(dbgi, irg, block, op_Div, mode_T, 3, in);
- res->attr.divmod.resmode = resmode;
- res->attr.divmod.no_remainder = 1;
- res->attr.divmod.exc.pin_state = pin_state;
+ res->attr.div.resmode = resmode;
+ res->attr.div.no_remainder = 1;
+ res->attr.div.exc.pin_state = pin_state;
res = optimize_node(res);
irn_verify_irg(res, irg);
return res;
void set_cur_block(ir_node *target)
{
+ assert(target == NULL || current_ir_graph == get_irn_irg(target));
current_ir_graph->current_block = target;
}
void set_r_cur_block(ir_graph *irg, ir_node *target)
{
+ assert(target == NULL || irg == get_irn_irg(target));
irg->current_block = target;
}
ir_node *get_r_value(ir_graph *irg, int pos, ir_mode *mode)
{
assert(get_irg_phase_state(irg) == phase_building);
- inc_irg_visited(irg);
-
assert(pos >= 0);
return get_r_value_internal(irg->current_block, pos + 1, mode);
int r_find_value(ir_graph *irg, ir_node *value)
{
- int i;
+ size_t i;
ir_node *bl = irg->current_block;
- for (i = ARR_LEN(bl->attr.block.graph_arr) - 1; i >= 1; --i)
- if (bl->attr.block.graph_arr[i] == value)
+ for (i = ARR_LEN(bl->attr.block.graph_arr); i > 1;) {
+ if (bl->attr.block.graph_arr[--i] == value)
return i - 1;
+ }
return -1;
}
ir_node *get_r_store(ir_graph *irg)
{
assert(get_irg_phase_state(irg) == phase_building);
- inc_irg_visited(irg);
return get_r_value_internal(irg->current_block, 0, mode_M);
}
set_r_store(current_ir_graph, store);
}
-void r_keep_alive(ir_graph *irg, ir_node *ka)
-{
- add_End_keepalive(get_irg_end(irg), ka);
-}
-
void keep_alive(ir_node *ka)
{
- r_keep_alive(current_ir_graph, ka);
+ ir_graph *irg = get_irn_irg(ka);
+ add_End_keepalive(get_irg_end(irg), ka);
}
void ir_set_uninitialized_local_variable_func(
void irp_finalize_cons(void)
{
- int i;
- for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
+ size_t i, n;
+ for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
irg_finalize_cons(get_irp_irg(i));
}
irp->phase_state = phase_high;
projects / libfirm / blobdiff