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));
/* 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
*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
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);
+ /* 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));
- /* The result of the phi is defined by this phi node. */
- SSA_NAME_DEF_STMT (PHI_RESULT (*phi)) = *phi;
-
- release_phi_node (old_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)++;
+ 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
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)--;
}
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