definitions created when a variable is used without a preceding
definition). */
-tree
+static tree
make_phi_node (tree var, int len)
{
tree phi;
+ int capacity;
- 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;
+ PHI_NUM_ARGS (phi) = len;
+ PHI_ARG_CAPACITY (phi) = capacity;
TREE_TYPE (phi) = TREE_TYPE (var);
if (TREE_CODE (var) == SSA_NAME)
SET_PHI_RESULT (phi, var);
int old_size;
tree new_phi;
- gcc_assert (len >= PHI_ARG_CAPACITY (*phi));
+ gcc_assert (len > PHI_ARG_CAPACITY (*phi));
- /* Note that OLD_SIZE is guaranteed to be smaller than SIZE. */
+ /* 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
+ portion of the PHI node currently in use. */
old_size = (sizeof (struct tree_phi_node)
- + (PHI_ARG_CAPACITY (*phi) - 1) * sizeof (struct phi_arg_d));
+ + (PHI_NUM_ARGS (*phi) - 1) * sizeof (struct phi_arg_d));
new_phi = allocate_phi_node (len);
*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 = &(bb_ann (bb)->phi_nodes);
+ *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
void
add_phi_arg (tree *phi, tree def, edge e)
{
- int i = PHI_NUM_ARGS (*phi);
-
- if (i >= PHI_ARG_CAPACITY (*phi))
- {
- tree old_phi = *phi;
- basic_block bb;
-
- /* 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;
+ basic_block bb = e->dest;
- /* Extract the basic block for the PHI from the PHI's annotation
- rather than the edge. This works better as the edge's
- destination may not currently be the block with the PHI node
- if we are in the process of threading the edge to a new
- destination. */
- bb = bb_for_stmt (*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. */
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)++;
-}
-
-/* Remove a PHI argument from PHI. BLOCK is the predecessor block where
- the PHI argument is coming from. */
-
-void
-remove_phi_arg (tree phi, basic_block block)
-{
- int i, num_elem = PHI_NUM_ARGS (phi);
-
- for (i = 0; i < num_elem; i++)
- {
- basic_block src_bb;
-
- src_bb = PHI_ARG_EDGE (phi, i)->src;
-
- if (src_bb == block)
- {
- remove_phi_arg_num (phi, i);
- return;
- }
- }
+ SET_PHI_ARG_DEF (*phi, e->dest_idx, def);
+ PHI_ARG_NONZERO (*phi, e->dest_idx) = false;
}
-
/* 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
+static void
remove_phi_arg_num (tree phi, int i)
{
int num_elem = PHI_NUM_ARGS (phi);
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);
}
/* 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 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_NUM_ARGS (phi)--;
}
+/* Remove all PHI arguments associated with edge E. */
+
+void
+remove_phi_args (edge e)
+{
+ 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 node PHI from basic block BB. If PREV is non-NULL, it is
used as the node immediately before PHI in the linked list. */
FOR_EACH_BB (bb)
{
/* Build a new PHI list for BB without variables in VARS. */
- tree phi, new_phi_list, last_phi, next;
+ tree phi, new_phi_list, next;
+ tree *lastp = &new_phi_list;
- last_phi = new_phi_list = NULL_TREE;
- for (phi = phi_nodes (bb), next = NULL; phi; phi = next)
+ for (phi = phi_nodes (bb); phi; phi = next)
{
tree var = SSA_NAME_VAR (PHI_RESULT (phi));
Note that fact in PHI_REWRITTEN. */
PHI_REWRITTEN (phi) = 1;
- if (new_phi_list == NULL_TREE)
- new_phi_list = last_phi = phi;
- else
- {
- PHI_CHAIN (last_phi) = phi;
- last_phi = phi;
- }
+ *lastp = phi;
+ lastp = &PHI_CHAIN (phi);
}
else
{
}
/* Make sure the last node in the new list has no successors. */
- if (last_phi)
- PHI_CHAIN (last_phi) = NULL_TREE;
+ *lastp = NULL;
bb_ann (bb)->phi_nodes = new_phi_list;
#if defined ENABLE_CHECKING
}
}
+/* Reverse the order of PHI nodes in the chain PHI.
+ Return the new head of the chain (old last PHI node). */
+
+tree
+phi_reverse (tree phi)
+{
+ tree prev = NULL_TREE, next;
+ for (; phi; phi = next)
+ {
+ next = PHI_CHAIN (phi);
+ PHI_CHAIN (phi) = prev;
+ prev = phi;
+ }
+ return prev;
+}
#include "gt-tree-phinodes.h"
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