/* Generic routines for manipulating PHIs
- Copyright (C) 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2005, 2007 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
+the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
return new_len;
}
-/* Return a PHI node for variable VAR defined in statement STMT.
- STMT may be an empty statement for artificial references (e.g., default
- definitions created when a variable is used without a preceding
- definition). */
+
+/* Return a PHI node with LEN argument slots for variable VAR. */
static tree
make_phi_node (tree var, int len)
{
tree phi;
+ int capacity, i;
- len = ideal_phi_node_len (len);
+ capacity = ideal_phi_node_len (len);
- phi = allocate_phi_node (len);
+ phi = allocate_phi_node (capacity);
- /* We do not have to clear a part of the PHI node that stores PHI
- arguments, which is safe because we tell the garbage collector to
- scan up to num_args elements in the array of PHI arguments. In
- other words, the garbage collector will not follow garbage
- pointers in the unused portion of the array. */
- memset (phi, 0, sizeof (struct tree_phi_node) - sizeof (struct phi_arg_d));
+ /* We need to clear the entire PHI node, including the argument
+ portion, because we represent a "missing PHI argument" by placing
+ NULL_TREE in PHI_ARG_DEF. */
+ memset (phi, 0, (sizeof (struct tree_phi_node) - sizeof (struct phi_arg_d)
+ + sizeof (struct phi_arg_d) * len));
TREE_SET_CODE (phi, PHI_NODE);
- PHI_ARG_CAPACITY (phi) = len;
- TREE_TYPE (phi) = TREE_TYPE (var);
+ PHI_NUM_ARGS (phi) = len;
+ PHI_ARG_CAPACITY (phi) = capacity;
if (TREE_CODE (var) == SSA_NAME)
SET_PHI_RESULT (phi, var);
else
SET_PHI_RESULT (phi, make_ssa_name (var, phi));
+ for (i = 0; i < capacity; i++)
+ {
+ use_operand_p imm;
+ imm = &(PHI_ARG_IMM_USE_NODE (phi, i));
+ imm->use = &(PHI_ARG_DEF_TREE (phi, i));
+ imm->prev = NULL;
+ imm->next = NULL;
+ imm->stmt = phi;
+ }
+
return phi;
}
{
int bucket;
int len = PHI_ARG_CAPACITY (phi);
+ int x;
+
+ for (x = 0; x < PHI_NUM_ARGS (phi); x++)
+ {
+ use_operand_p imm;
+ imm = &(PHI_ARG_IMM_USE_NODE (phi, x));
+ delink_imm_use (imm);
+ }
bucket = len > NUM_BUCKETS - 1 ? NUM_BUCKETS - 1 : len;
bucket -= 2;
static void
resize_phi_node (tree *phi, int len)
{
- int old_size;
+ int old_size, i;
tree new_phi;
- gcc_assert (len >= PHI_ARG_CAPACITY (*phi));
+ gcc_assert (len > PHI_ARG_CAPACITY (*phi));
/* The garbage collector will not look at the PHI node beyond the
first PHI_NUM_ARGS elements. Therefore, all we have to copy is a
memcpy (new_phi, *phi, old_size);
+ for (i = 0; i < PHI_NUM_ARGS (new_phi); i++)
+ {
+ use_operand_p imm, old_imm;
+ imm = &(PHI_ARG_IMM_USE_NODE (new_phi, i));
+ old_imm = &(PHI_ARG_IMM_USE_NODE (*phi, i));
+ imm->use = &(PHI_ARG_DEF_TREE (new_phi, i));
+ relink_imm_use_stmt (imm, old_imm, new_phi);
+ }
+
PHI_ARG_CAPACITY (new_phi) = len;
+ for (i = PHI_NUM_ARGS (new_phi); i < len; i++)
+ {
+ use_operand_p imm;
+ imm = &(PHI_ARG_IMM_USE_NODE (new_phi, i));
+ imm->use = &(PHI_ARG_DEF_TREE (new_phi, i));
+ imm->prev = NULL;
+ imm->next = NULL;
+ imm->stmt = new_phi;
+ }
+
*phi = new_phi;
}
+/* Reserve PHI arguments for a new edge to basic block BB. */
+
+void
+reserve_phi_args_for_new_edge (basic_block bb)
+{
+ tree *loc;
+ int len = EDGE_COUNT (bb->preds);
+ int cap = ideal_phi_node_len (len + 4);
+
+ for (loc = phi_nodes_ptr (bb);
+ *loc;
+ loc = &PHI_CHAIN (*loc))
+ {
+ if (len > PHI_ARG_CAPACITY (*loc))
+ {
+ tree old_phi = *loc;
+
+ resize_phi_node (loc, cap);
+
+ /* The result of the phi is defined by this phi node. */
+ SSA_NAME_DEF_STMT (PHI_RESULT (*loc)) = *loc;
+
+ release_phi_node (old_phi);
+ }
+
+ /* We represent a "missing PHI argument" by placing NULL_TREE in
+ the corresponding slot. If PHI arguments were added
+ immediately after an edge is created, this zeroing would not
+ be necessary, but unfortunately this is not the case. For
+ example, the loop optimizer duplicates several basic blocks,
+ redirects edges, and then fixes up PHI arguments later in
+ batch. */
+ SET_PHI_ARG_DEF (*loc, len - 1, NULL_TREE);
+
+ PHI_NUM_ARGS (*loc)++;
+ }
+}
+
+
/* Create a new PHI node for variable VAR at basic block BB. */
tree
/* Add the new PHI node to the list of PHI nodes for block BB. */
PHI_CHAIN (phi) = phi_nodes (bb);
- bb_ann (bb)->phi_nodes = phi;
+ set_phi_nodes (bb, phi);
/* Associate BB to the PHI node. */
set_bb_for_stmt (phi, bb);
return phi;
}
+
/* Add a new argument to PHI node PHI. DEF is the incoming reaching
definition and E is the edge through which DEF reaches PHI. The new
argument is added at the end of the argument list.
PHI points to the reallocated phi node when we return. */
void
-add_phi_arg (tree *phi, tree def, edge e)
+add_phi_arg (tree phi, tree def, edge e)
{
basic_block bb = e->dest;
- int i = PHI_NUM_ARGS (*phi);
-
- gcc_assert (bb == bb_for_stmt (*phi));
-
- if (i >= PHI_ARG_CAPACITY (*phi))
- {
- tree old_phi = *phi;
-
- /* Resize the phi. Unfortunately, this will relocate it. */
- resize_phi_node (phi, ideal_phi_node_len (i + 4));
-
- /* resize_phi_node will necessarily relocate the phi. */
- gcc_assert (*phi != old_phi);
- /* The result of the phi is defined by this phi node. */
- SSA_NAME_DEF_STMT (PHI_RESULT (*phi)) = *phi;
+ gcc_assert (bb == bb_for_stmt (phi));
- release_phi_node (old_phi);
+ /* We resize PHI nodes upon edge creation. We should always have
+ enough room at this point. */
+ gcc_assert (PHI_NUM_ARGS (phi) <= PHI_ARG_CAPACITY (phi));
- /* Update the list head if replacing the first listed phi. */
- if (phi_nodes (bb) == old_phi)
- bb_ann (bb)->phi_nodes = *phi;
- else
- {
- /* Traverse the list looking for the phi node to chain to. */
- tree p;
-
- for (p = phi_nodes (bb);
- p && PHI_CHAIN (p) != old_phi;
- p = PHI_CHAIN (p))
- ;
-
- gcc_assert (p);
- PHI_CHAIN (p) = *phi;
- }
- }
+ /* We resize PHI nodes upon edge creation. We should always have
+ enough room at this point. */
+ gcc_assert (e->dest_idx < (unsigned int) PHI_NUM_ARGS (phi));
/* Copy propagation needs to know what object occur in abnormal
PHI nodes. This is a convenient place to record such information. */
if (e->flags & EDGE_ABNORMAL)
{
SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def) = 1;
- SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (*phi)) = 1;
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)) = 1;
}
- SET_PHI_ARG_DEF (*phi, i, def);
- PHI_ARG_EDGE (*phi, i) = e;
- PHI_ARG_NONZERO (*phi, i) = false;
- PHI_NUM_ARGS (*phi)++;
+ SET_PHI_ARG_DEF (phi, e->dest_idx, def);
}
-/* Remove the Ith argument from PHI's argument list. This routine assumes
- ordering of alternatives in the vector is not important and implements
- removal by swapping the last alternative with the alternative we want to
- delete, then shrinking the vector. */
-void
+/* Remove the Ith argument from PHI's argument list. This routine
+ implements removal by swapping the last alternative with the
+ alternative we want to delete and then shrinking the vector, which
+ is consistent with how we remove an edge from the edge vector. */
+
+static void
remove_phi_arg_num (tree phi, int i)
{
int num_elem = PHI_NUM_ARGS (phi);
gcc_assert (i < num_elem);
- /* If we are not at the last element, switch the last element
- with the element we want to delete. */
+ /* Delink the item which is being removed. */
+ delink_imm_use (&(PHI_ARG_IMM_USE_NODE (phi, i)));
+
+ /* If it is not the last element, move the last element
+ to the element we want to delete, resetting all the links. */
if (i != num_elem - 1)
{
- SET_PHI_ARG_DEF (phi, i, PHI_ARG_DEF (phi, num_elem - 1));
- PHI_ARG_EDGE (phi, i) = PHI_ARG_EDGE (phi, num_elem - 1);
- PHI_ARG_NONZERO (phi, i) = PHI_ARG_NONZERO (phi, num_elem - 1);
+ use_operand_p old_p, new_p;
+ old_p = &PHI_ARG_IMM_USE_NODE (phi, num_elem - 1);
+ new_p = &PHI_ARG_IMM_USE_NODE (phi, i);
+ /* Set use on new node, and link into last element's place. */
+ *(new_p->use) = *(old_p->use);
+ relink_imm_use (new_p, old_p);
}
/* Shrink the vector and return. Note that we do not have to clear
- PHI_ARG_DEF, PHI_ARG_EDGE, or PHI_ARG_NONZERO because the garbage
- collector will not look at those elements beyond the first
- PHI_NUM_ARGS elements of the array. */
+ PHI_ARG_DEF because the garbage collector will not look at those
+ elements beyond the first PHI_NUM_ARGS elements of the array. */
PHI_NUM_ARGS (phi)--;
}
+
/* Remove all PHI arguments associated with edge E. */
void
tree phi;
for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
- {
- int index = phi_arg_from_edge (phi, e);
- if (index >= 0)
- remove_phi_arg_num (phi, index);
- }
+ remove_phi_arg_num (phi, e->dest_idx);
}
+
/* Remove PHI node PHI from basic block BB. If PREV is non-NULL, it is
- used as the node immediately before PHI in the linked list. */
+ used as the node immediately before PHI in the linked list. If
+ RELEASE_LHS_P is true, the LHS of this PHI node is released into
+ the free pool of SSA names. */
void
-remove_phi_node (tree phi, tree prev, basic_block bb)
+remove_phi_node (tree phi, tree prev, bool release_lhs_p)
{
- if (prev)
- {
- /* Rewire the list if we are given a PREV pointer. */
- PHI_CHAIN (prev) = PHI_CHAIN (phi);
+ tree *loc;
- /* If we are deleting the PHI node, then we should release the
- SSA_NAME node so that it can be reused. */
- release_ssa_name (PHI_RESULT (phi));
- release_phi_node (phi);
- }
- else if (phi == phi_nodes (bb))
+ if (prev)
{
- /* Update the list head if removing the first element. */
- bb_ann (bb)->phi_nodes = PHI_CHAIN (phi);
-
- /* If we are deleting the PHI node, then we should release the
- SSA_NAME node so that it can be reused. */
- release_ssa_name (PHI_RESULT (phi));
- release_phi_node (phi);
+ loc = &PHI_CHAIN (prev);
}
else
{
- /* Traverse the list looking for the node to remove. */
- tree prev, t;
- prev = NULL_TREE;
- for (t = phi_nodes (bb); t && t != phi; t = PHI_CHAIN (t))
- prev = t;
- if (t)
- remove_phi_node (t, prev, bb);
+ for (loc = phi_nodes_ptr (bb_for_stmt (phi));
+ *loc != phi;
+ loc = &PHI_CHAIN (*loc))
+ ;
}
-}
-
-
-/* Remove all the PHI nodes for variables in the VARS bitmap. */
-void
-remove_all_phi_nodes_for (bitmap vars)
-{
- basic_block bb;
+ /* Remove PHI from the chain. */
+ *loc = PHI_CHAIN (phi);
- FOR_EACH_BB (bb)
- {
- /* Build a new PHI list for BB without variables in VARS. */
- tree phi, new_phi_list, next;
- tree *lastp = &new_phi_list;
-
- for (phi = phi_nodes (bb); phi; phi = next)
- {
- tree var = SSA_NAME_VAR (PHI_RESULT (phi));
-
- next = PHI_CHAIN (phi);
- /* Only add PHI nodes for variables not in VARS. */
- if (!bitmap_bit_p (vars, var_ann (var)->uid))
- {
- /* If we're not removing this PHI node, then it must have
- been rewritten by a previous call into the SSA rewriter.
- Note that fact in PHI_REWRITTEN. */
- PHI_REWRITTEN (phi) = 1;
-
- *lastp = phi;
- lastp = &PHI_CHAIN (phi);
- }
- else
- {
- /* If we are deleting the PHI node, then we should release the
- SSA_NAME node so that it can be reused. */
- release_ssa_name (PHI_RESULT (phi));
- release_phi_node (phi);
- }
- }
-
- /* Make sure the last node in the new list has no successors. */
- *lastp = NULL;
- bb_ann (bb)->phi_nodes = new_phi_list;
-
-#if defined ENABLE_CHECKING
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- {
- tree var = SSA_NAME_VAR (PHI_RESULT (phi));
- gcc_assert (!bitmap_bit_p (vars, var_ann (var)->uid));
- }
-#endif
- }
+ /* If we are deleting the PHI node, then we should release the
+ SSA_NAME node so that it can be reused. */
+ release_phi_node (phi);
+ if (release_lhs_p)
+ release_ssa_name (PHI_RESULT (phi));
}
+
/* Reverse the order of PHI nodes in the chain PHI.
Return the new head of the chain (old last PHI node). */
}
#include "gt-tree-phinodes.h"
-