/* Generic routines for manipulating PHIs
- Copyright (C) 2003, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2003-2020 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"
#include "coretypes.h"
-#include "tm.h"
+#include "backend.h"
#include "tree.h"
-#include "rtl.h"
-#include "varray.h"
-#include "ggc.h"
-#include "basic-block.h"
-#include "tree-flow.h"
-#include "toplev.h"
+#include "gimple.h"
+#include "ssa.h"
+#include "fold-const.h"
+#include "gimple-iterator.h"
+#include "tree-ssa.h"
/* Rewriting a function into SSA form can create a huge number of PHIs
many of which may be thrown away shortly after their creation if jumps
garbage collector. Similar results have been seen on a wider variety
of tests (such as the compiler itself).
- Right now we maintain our free list on a per-function basis. It may
- or may not make sense to maintain the free list for the duration of
- a compilation unit.
-
- We could also use a zone allocator for these objects since they have
- a very well defined lifetime. If someone wants to experiment with that
- this is the place to try it.
-
PHI nodes have different sizes, so we can't have a single list of all
the PHI nodes as it would be too expensive to walk down that list to
find a PHI of a suitable size.
the -2 on all the calculations below. */
#define NUM_BUCKETS 10
-static GTY ((deletable (""))) tree free_phinodes[NUM_BUCKETS - 2];
+static GTY ((deletable (""))) vec<gimple *, va_gc> *free_phinodes[NUM_BUCKETS - 2];
static unsigned long free_phinode_count;
static int ideal_phi_node_len (int);
-static void resize_phi_node (tree *, int);
-#ifdef GATHER_STATISTICS
unsigned int phi_nodes_reused;
unsigned int phi_nodes_created;
-#endif
-
-/* Initialize management of PHIs. */
-
-void
-init_phinodes (void)
-{
- int i;
-
- for (i = 0; i < NUM_BUCKETS - 2; i++)
- free_phinodes[i] = NULL;
- free_phinode_count = 0;
-}
-
-/* Finalize management of PHIs. */
-
-void
-fini_phinodes (void)
-{
- int i;
-
- for (i = 0; i < NUM_BUCKETS - 2; i++)
- free_phinodes[i] = NULL;
- free_phinode_count = 0;
-}
/* Dump some simple statistics regarding the re-use of PHI nodes. */
-#ifdef GATHER_STATISTICS
void
phinodes_print_statistics (void)
{
- fprintf (stderr, "PHI nodes allocated: %u\n", phi_nodes_created);
- fprintf (stderr, "PHI nodes reused: %u\n", phi_nodes_reused);
+ fprintf (stderr, "%-32s" PRsa (11) "\n", "PHI nodes allocated:",
+ SIZE_AMOUNT (phi_nodes_created));
+ fprintf (stderr, "%-32s" PRsa (11) "\n", "PHI nodes reused:",
+ SIZE_AMOUNT (phi_nodes_reused));
}
-#endif
/* Allocate a PHI node with at least LEN arguments. If the free list
happens to contain a PHI node with LEN arguments or more, return
that one. */
-static inline tree
-allocate_phi_node (int len)
+static inline gphi *
+allocate_phi_node (size_t len)
{
- tree phi;
- int bucket = NUM_BUCKETS - 2;
- int size = (sizeof (struct tree_phi_node)
- + (len - 1) * sizeof (struct phi_arg_d));
+ gphi *phi;
+ size_t bucket = NUM_BUCKETS - 2;
+ size_t size = sizeof (struct gphi)
+ + (len - 1) * sizeof (struct phi_arg_d);
if (free_phinode_count)
for (bucket = len - 2; bucket < NUM_BUCKETS - 2; bucket++)
/* If our free list has an element, then use it. */
if (bucket < NUM_BUCKETS - 2
- && PHI_ARG_CAPACITY (free_phinodes[bucket]) >= len)
+ && gimple_phi_capacity ((*free_phinodes[bucket])[0]) >= len)
{
free_phinode_count--;
- phi = free_phinodes[bucket];
- free_phinodes[bucket] = PHI_CHAIN (free_phinodes[bucket]);
-#ifdef GATHER_STATISTICS
- phi_nodes_reused++;
-#endif
+ phi = as_a <gphi *> (free_phinodes[bucket]->pop ());
+ if (free_phinodes[bucket]->is_empty ())
+ vec_free (free_phinodes[bucket]);
+ if (GATHER_STATISTICS)
+ phi_nodes_reused++;
}
else
{
- phi = ggc_alloc (size);
-#ifdef GATHER_STATISTICS
- phi_nodes_created++;
- tree_node_counts[(int) phi_kind]++;
- tree_node_sizes[(int) phi_kind] += size;
-#endif
+ phi = static_cast <gphi *> (ggc_internal_alloc (size));
+ if (GATHER_STATISTICS)
+ {
+ enum gimple_alloc_kind kind = gimple_alloc_kind (GIMPLE_PHI);
+ phi_nodes_created++;
+ gimple_alloc_counts[(int) kind]++;
+ gimple_alloc_sizes[(int) kind] += size;
+ }
}
return phi;
len = 2;
/* Compute the number of bytes of the original request. */
- size = sizeof (struct tree_phi_node) + (len - 1) * sizeof (struct phi_arg_d);
+ size = sizeof (struct gphi)
+ + (len - 1) * sizeof (struct phi_arg_d);
/* Round it up to the next power of two. */
log2 = ceil_log2 (size);
return new_len;
}
-
/* Return a PHI node with LEN argument slots for variable VAR. */
-static tree
+static gphi *
make_phi_node (tree var, int len)
{
- tree phi;
+ gphi *phi;
int capacity, i;
capacity = ideal_phi_node_len (len);
/* 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)
+ memset (phi, 0, (sizeof (struct gphi)
+ - sizeof (struct phi_arg_d)
+ sizeof (struct phi_arg_d) * len));
- TREE_SET_CODE (phi, PHI_NODE);
- 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);
+ phi->code = GIMPLE_PHI;
+ gimple_init_singleton (phi);
+ phi->nargs = len;
+ phi->capacity = capacity;
+ if (!var)
+ ;
+ else if (TREE_CODE (var) == SSA_NAME)
+ gimple_phi_set_result (phi, var);
else
- SET_PHI_RESULT (phi, make_ssa_name (var, phi));
+ gimple_phi_set_result (phi, make_ssa_name (var, phi));
- for (i = 0; i < capacity; i++)
+ for (i = 0; i < len; i++)
{
use_operand_p imm;
- imm = &(PHI_ARG_IMM_USE_NODE (phi, i));
- imm->use = &(PHI_ARG_DEF_TREE (phi, i));
+
+ gimple_phi_arg_set_location (phi, i, UNKNOWN_LOCATION);
+ imm = gimple_phi_arg_imm_use_ptr (phi, i);
+ imm->use = gimple_phi_arg_def_ptr (phi, i);
imm->prev = NULL;
imm->next = NULL;
- imm->stmt = phi;
+ imm->loc.stmt = phi;
}
+
return phi;
}
/* We no longer need PHI, release it so that it may be reused. */
-void
-release_phi_node (tree phi)
+static void
+release_phi_node (gimple *phi)
{
- int bucket;
- int len = PHI_ARG_CAPACITY (phi);
- int x;
+ size_t bucket;
+ size_t len = gimple_phi_capacity (phi);
+ size_t x;
- for (x = 0; x < PHI_NUM_ARGS (phi); x++)
+ for (x = 0; x < gimple_phi_num_args (phi); x++)
{
use_operand_p imm;
- imm = &(PHI_ARG_IMM_USE_NODE (phi, x));
+ imm = gimple_phi_arg_imm_use_ptr (phi, x);
delink_imm_use (imm);
}
bucket = len > NUM_BUCKETS - 1 ? NUM_BUCKETS - 1 : len;
bucket -= 2;
- PHI_CHAIN (phi) = free_phinodes[bucket];
- free_phinodes[bucket] = phi;
+ vec_safe_push (free_phinodes[bucket], phi);
free_phinode_count++;
}
+
/* Resize an existing PHI node. The only way is up. Return the
possibly relocated phi. */
-static void
-resize_phi_node (tree *phi, int len)
+static gphi *
+resize_phi_node (gphi *phi, size_t len)
{
- int old_size, i;
- tree new_phi;
+ size_t old_size, i;
+ gphi *new_phi;
- gcc_assert (len > PHI_ARG_CAPACITY (*phi));
+ gcc_assert (len > gimple_phi_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
portion of the PHI node currently in use. */
- old_size = (sizeof (struct tree_phi_node)
- + (PHI_NUM_ARGS (*phi) - 1) * sizeof (struct phi_arg_d));
+ old_size = sizeof (struct gphi)
+ + (gimple_phi_num_args (phi) - 1) * sizeof (struct phi_arg_d);
new_phi = allocate_phi_node (len);
- memcpy (new_phi, *phi, old_size);
+ memcpy (new_phi, phi, old_size);
+ memset ((char *)new_phi + old_size, 0,
+ (sizeof (struct gphi)
+ - sizeof (struct phi_arg_d)
+ + sizeof (struct phi_arg_d) * len) - old_size);
- for (i = 0; i < PHI_NUM_ARGS (new_phi); i++)
+ for (i = 0; i < gimple_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));
+ imm = gimple_phi_arg_imm_use_ptr (new_phi, i);
+ old_imm = gimple_phi_arg_imm_use_ptr (phi, i);
+ imm->use = gimple_phi_arg_def_ptr (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;
- }
-
+ new_phi->capacity = len;
- *phi = new_phi;
+ return 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);
+ size_t len = EDGE_COUNT (bb->preds);
+ size_t cap = ideal_phi_node_len (len + 4);
+ gphi_iterator gsi;
- for (loc = &(bb_ann (bb)->phi_nodes);
- *loc;
- loc = &PHI_CHAIN (*loc))
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- if (len > PHI_ARG_CAPACITY (*loc))
- {
- tree old_phi = *loc;
+ gphi *stmt = gsi.phi ();
- resize_phi_node (loc, cap);
+ if (len > gimple_phi_capacity (stmt))
+ {
+ gphi *new_phi = resize_phi_node (stmt, cap);
- /* The result of the phi is defined by this phi node. */
- SSA_NAME_DEF_STMT (PHI_RESULT (*loc)) = *loc;
+ /* The result of the PHI is defined by this PHI node. */
+ SSA_NAME_DEF_STMT (gimple_phi_result (new_phi)) = new_phi;
+ gsi_set_stmt (&gsi, new_phi);
- release_phi_node (old_phi);
+ release_phi_node (stmt);
+ stmt = new_phi;
}
+ stmt->nargs++;
+
/* 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
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)++;
+ use_operand_p imm = gimple_phi_arg_imm_use_ptr (stmt, len - 1);
+ imm->use = gimple_phi_arg_def_ptr (stmt, len - 1);
+ imm->prev = NULL;
+ imm->next = NULL;
+ imm->loc.stmt = stmt;
+ SET_PHI_ARG_DEF (stmt, len - 1, NULL_TREE);
+ gimple_phi_arg_set_location (stmt, len - 1, UNKNOWN_LOCATION);
}
}
-/* Create a new PHI node for variable VAR at basic block BB. */
+/* Adds PHI to BB. */
-tree
-create_phi_node (tree var, basic_block bb)
+void
+add_phi_node_to_bb (gphi *phi, basic_block bb)
{
- tree phi;
-
- phi = make_phi_node (var, EDGE_COUNT (bb->preds));
-
+ gimple_seq seq = phi_nodes (bb);
/* 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;
+ if (seq == NULL)
+ set_phi_nodes (bb, gimple_seq_alloc_with_stmt (phi));
+ else
+ {
+ gimple_seq_add_stmt (&seq, phi);
+ gcc_assert (seq == phi_nodes (bb));
+ }
/* Associate BB to the PHI node. */
- set_bb_for_stmt (phi, bb);
+ gimple_set_bb (phi, bb);
+
+}
+
+/* Create a new PHI node for variable VAR at basic block BB. */
+gphi *
+create_phi_node (tree var, basic_block bb)
+{
+ gphi *phi = make_phi_node (var, EDGE_COUNT (bb->preds));
+
+ add_phi_node_to_bb (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 (gphi *phi, tree def, edge e, location_t locus)
{
basic_block bb = e->dest;
- gcc_assert (bb == bb_for_stmt (phi));
+ gcc_assert (bb == gimple_bb (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));
+ gcc_assert (gimple_phi_num_args (phi) <= gimple_phi_capacity (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));
+ gcc_assert (e->dest_idx < gimple_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. */
}
SET_PHI_ARG_DEF (phi, e->dest_idx, def);
- PHI_ARG_NONZERO (phi, e->dest_idx) = false;
+ gimple_phi_arg_set_location (phi, e->dest_idx, locus);
}
+
/* 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)
+remove_phi_arg_num (gphi *phi, int i)
{
- int num_elem = PHI_NUM_ARGS (phi);
+ int num_elem = gimple_phi_num_args (phi);
gcc_assert (i < num_elem);
- /* Delink the last item, which is being removed. */
- delink_imm_use (&(PHI_ARG_IMM_USE_NODE (phi, num_elem - 1)));
+ /* Delink the item which is being removed. */
+ delink_imm_use (gimple_phi_arg_imm_use_ptr (phi, i));
- /* If we are not at the last element, switch the last element
- with the element we want to delete. */
+ /* 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_NONZERO (phi, i) = PHI_ARG_NONZERO (phi, num_elem - 1);
+ use_operand_p old_p, new_p;
+ old_p = gimple_phi_arg_imm_use_ptr (phi, num_elem - 1);
+ new_p = gimple_phi_arg_imm_use_ptr (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);
+ /* Move the location as well. */
+ gimple_phi_arg_set_location (phi, i,
+ gimple_phi_arg_location (phi, num_elem - 1));
}
/* Shrink the vector and return. Note that we do not have to clear
- 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)--;
+ PHI_ARG_DEF because the garbage collector will not look at those
+ elements beyond the first PHI_NUM_ARGS elements of the array. */
+ phi->nargs--;
}
+
/* Remove all PHI arguments associated with edge E. */
void
remove_phi_args (edge e)
{
- tree phi;
+ gphi_iterator gsi;
- for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
- remove_phi_arg_num (phi, e->dest_idx);
+ for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
+ remove_phi_arg_num (gsi.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. */
+
+/* Remove the PHI node pointed-to by iterator GSI from basic block BB. After
+ removal, iterator GSI is updated to point to the next PHI node in the
+ sequence. 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)
+remove_phi_node (gimple_stmt_iterator *gsi, bool release_lhs_p)
{
- tree *loc;
+ gimple *phi = gsi_stmt (*gsi);
- if (prev)
- {
- loc = &PHI_CHAIN (prev);
- }
- else
- {
- for (loc = &(bb_ann (bb_for_stmt (phi))->phi_nodes);
- *loc != phi;
- loc = &PHI_CHAIN (*loc))
- ;
- }
+ if (release_lhs_p)
+ insert_debug_temps_for_defs (gsi);
- /* Remove PHI from the chain. */
- *loc = PHI_CHAIN (phi);
+ gsi_remove (gsi, false);
/* 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);
- release_ssa_name (PHI_RESULT (phi));
+ if (release_lhs_p)
+ release_ssa_name (gimple_phi_result (phi));
}
+/* Remove all the phi nodes from BB. */
+
+void
+remove_phi_nodes (basic_block bb)
+{
+ gphi_iterator gsi;
+
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
+ remove_phi_node (&gsi, true);
+
+ set_phi_nodes (bb, NULL);
+}
-/* Reverse the order of PHI nodes in the chain PHI.
- Return the new head of the chain (old last PHI node). */
+/* Given PHI, return its RHS if the PHI is a degenerate, otherwise return
+ NULL. */
tree
-phi_reverse (tree phi)
+degenerate_phi_result (gphi *phi)
{
- tree prev = NULL_TREE, next;
- for (; phi; phi = next)
+ tree lhs = gimple_phi_result (phi);
+ tree val = NULL;
+ size_t i;
+
+ /* Ignoring arguments which are the same as LHS, if all the remaining
+ arguments are the same, then the PHI is a degenerate and has the
+ value of that common argument. */
+ for (i = 0; i < gimple_phi_num_args (phi); i++)
{
- next = PHI_CHAIN (phi);
- PHI_CHAIN (phi) = prev;
- prev = phi;
+ tree arg = gimple_phi_arg_def (phi, i);
+
+ if (arg == lhs)
+ continue;
+ else if (!arg)
+ break;
+ else if (!val)
+ val = arg;
+ else if (arg == val)
+ continue;
+ /* We bring in some of operand_equal_p not only to speed things
+ up, but also to avoid crashing when dereferencing the type of
+ a released SSA name. */
+ else if (TREE_CODE (val) != TREE_CODE (arg)
+ || TREE_CODE (val) == SSA_NAME
+ || !operand_equal_p (arg, val, 0))
+ break;
}
- return prev;
+ return (i == gimple_phi_num_args (phi) ? val : NULL);
+}
+
+/* Set PHI nodes of a basic block BB to SEQ. */
+
+void
+set_phi_nodes (basic_block bb, gimple_seq seq)
+{
+ gimple_stmt_iterator i;
+
+ gcc_checking_assert (!(bb->flags & BB_RTL));
+ bb->il.gimple.phi_nodes = seq;
+ if (seq)
+ for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i))
+ gimple_set_bb (gsi_stmt (i), bb);
}
#include "gt-tree-phinodes.h"
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