/* Control flow functions for trees.
- Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
This file is part of GCC.
#include "except.h"
#include "cfgloop.h"
#include "cfglayout.h"
+#include "hashtab.h"
/* This file contains functions for building the Control Flow Graph (CFG)
for a function tree. */
building of the CFG in code with lots of gotos. */
static GTY(()) varray_type label_to_block_map;
+/* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
+ which use a particular edge. The CASE_LABEL_EXPRs are chained together
+ via their TREE_CHAIN field, which we clear after we're done with the
+ hash table to prevent problems with duplication of SWITCH_EXPRs.
+
+ Access to this list of CASE_LABEL_EXPRs allows us to efficiently
+ update the case vector in response to edge redirections.
+
+ Right now this table is set up and torn down at key points in the
+ compilation process. It would be nice if we could make the table
+ more persistent. The key is getting notification of changes to
+ the CFG (particularly edge removal, creation and redirection). */
+
+struct edge_to_cases_elt
+{
+ /* The edge itself. Necessary for hashing and equality tests. */
+ edge e;
+
+ /* The case labels associated with this edge. We link these up via
+ their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
+ when we destroy the hash table. This prevents problems when copying
+ SWITCH_EXPRs. */
+ tree case_labels;
+};
+
+static htab_t edge_to_cases;
+
/* CFG statistics. */
struct cfg_stats_d
{
static inline bool stmt_starts_bb_p (tree, tree);
static int tree_verify_flow_info (void);
static void tree_make_forwarder_block (edge);
-static bool thread_jumps (void);
static bool tree_forwarder_block_p (basic_block);
-static void bsi_commit_edge_inserts_1 (edge e);
static void tree_cfg2vcg (FILE *);
/* Flowgraph optimization and cleanup. */
static edge find_taken_edge_switch_expr (basic_block, tree);
static tree find_case_label_for_value (tree, tree);
static bool phi_alternatives_equal (basic_block, edge, edge);
+static bool cleanup_forwarder_blocks (void);
/*---------------------------------------------------------------------------
if (found_computed_goto)
factor_computed_gotos ();
- /* Make sure there is always at least one block, even if its empty. */
+ /* Make sure there is always at least one block, even if it's empty. */
if (n_basic_blocks == 0)
create_empty_bb (ENTRY_BLOCK_PTR);
gcc_assert (!e);
- /* Create and initialize a new basic block. */
+ /* Create and initialize a new basic block. Since alloc_block uses
+ ggc_alloc_cleared to allocate a basic block, we do not have to
+ clear the newly allocated basic block here. */
bb = alloc_block ();
- memset (bb, 0, sizeof (*bb));
bb->index = last_basic_block;
bb->flags = BB_NEW;
statements in it. */
make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
- /* Traverse basic block array placing edges. */
+ /* Traverse the basic block array placing edges. */
FOR_EACH_BB (bb)
{
tree first = first_stmt (bb);
such a bloody pain to avoid creating edges for this case since
all we do is remove these edges when we're done building the
CFG. */
- if (call_expr_flags (last) & (ECF_NORETURN | ECF_LONGJMP))
+ if (call_expr_flags (last) & ECF_NORETURN)
{
make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
return;
make_edge (bb, else_bb, EDGE_FALSE_VALUE);
}
+/* Hashing routine for EDGE_TO_CASES. */
+
+static hashval_t
+edge_to_cases_hash (const void *p)
+{
+ edge e = ((struct edge_to_cases_elt *)p)->e;
+
+ /* Hash on the edge itself (which is a pointer). */
+ return htab_hash_pointer (e);
+}
+
+/* Equality routine for EDGE_TO_CASES, edges are unique, so testing
+ for equality is just a pointer comparison. */
+
+static int
+edge_to_cases_eq (const void *p1, const void *p2)
+{
+ edge e1 = ((struct edge_to_cases_elt *)p1)->e;
+ edge e2 = ((struct edge_to_cases_elt *)p2)->e;
+
+ return e1 == e2;
+}
+
+/* Called for each element in the hash table (P) as we delete the
+ edge to cases hash table.
+
+ Clear all the TREE_CHAINs to prevent problems with copying of
+ SWITCH_EXPRs and structure sharing rules, then free the hash table
+ element. */
+
+static void
+edge_to_cases_cleanup (void *p)
+{
+ struct edge_to_cases_elt *elt = p;
+ tree t, next;
+
+ for (t = elt->case_labels; t; t = next)
+ {
+ next = TREE_CHAIN (t);
+ TREE_CHAIN (t) = NULL;
+ }
+ free (p);
+}
+
+/* Start recording information mapping edges to case labels. */
+
+static void
+start_recording_case_labels (void)
+{
+ gcc_assert (edge_to_cases == NULL);
+
+ edge_to_cases = htab_create (37,
+ edge_to_cases_hash,
+ edge_to_cases_eq,
+ edge_to_cases_cleanup);
+}
+
+/* Return nonzero if we are recording information for case labels. */
+
+static bool
+recording_case_labels_p (void)
+{
+ return (edge_to_cases != NULL);
+}
+
+/* Stop recording information mapping edges to case labels and
+ remove any information we have recorded. */
+static void
+end_recording_case_labels (void)
+{
+ htab_delete (edge_to_cases);
+ edge_to_cases = NULL;
+}
+
+/* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
+
+static void
+record_switch_edge (edge e, tree case_label)
+{
+ struct edge_to_cases_elt *elt;
+ void **slot;
+
+ /* Build a hash table element so we can see if E is already
+ in the table. */
+ elt = xmalloc (sizeof (struct edge_to_cases_elt));
+ elt->e = e;
+ elt->case_labels = case_label;
+
+ slot = htab_find_slot (edge_to_cases, elt, INSERT);
+
+ if (*slot == NULL)
+ {
+ /* E was not in the hash table. Install E into the hash table. */
+ *slot = (void *)elt;
+ }
+ else
+ {
+ /* E was already in the hash table. Free ELT as we do not need it
+ anymore. */
+ free (elt);
+
+ /* Get the entry stored in the hash table. */
+ elt = (struct edge_to_cases_elt *) *slot;
+
+ /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
+ TREE_CHAIN (case_label) = elt->case_labels;
+ elt->case_labels = case_label;
+ }
+}
+
+/* If we are inside a {start,end}_recording_cases block, then return
+ a chain of CASE_LABEL_EXPRs from T which reference E.
+
+ Otherwise return NULL. */
+
+static tree
+get_cases_for_edge (edge e, tree t)
+{
+ struct edge_to_cases_elt elt, *elt_p;
+ void **slot;
+ size_t i, n;
+ tree vec;
+
+ /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
+ chains available. Return NULL so the caller can detect this case. */
+ if (!recording_case_labels_p ())
+ return NULL;
+
+restart:
+ elt.e = e;
+ elt.case_labels = NULL;
+ slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
+
+ if (slot)
+ {
+ elt_p = (struct edge_to_cases_elt *)*slot;
+ return elt_p->case_labels;
+ }
+
+ /* If we did not find E in the hash table, then this must be the first
+ time we have been queried for information about E & T. Add all the
+ elements from T to the hash table then perform the query again. */
+
+ vec = SWITCH_LABELS (t);
+ n = TREE_VEC_LENGTH (vec);
+ for (i = 0; i < n; i++)
+ {
+ tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
+ basic_block label_bb = label_to_block (lab);
+ record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
+ }
+ goto restart;
+}
/* Create the edges for a SWITCH_EXPR starting at block BB.
At this point, the switch body has been lowered and the
{
int uid = LABEL_DECL_UID (dest);
- /* We would die hard when faced by undefined label. Emit label to
- very first basic block. This will hopefully make even the dataflow
+ /* We would die hard when faced by an undefined label. Emit a label to
+ the very first basic block. This will hopefully make even the dataflow
and undefined variable warnings quite right. */
if ((errorcount || sorrycount) && uid < 0)
{
bool
cleanup_tree_cfg (void)
{
- bool something_changed = true;
bool retval = false;
timevar_push (TV_TREE_CLEANUP_CFG);
- /* These three transformations can cascade, so we iterate on them until
- nothing changes. */
- while (something_changed)
+ retval = cleanup_control_flow ();
+ retval |= delete_unreachable_blocks ();
+
+ /* cleanup_forwarder_blocks can redirect edges out of SWITCH_EXPRs,
+ which can get expensive. So we want to enable recording of edge
+ to CASE_LABEL_EXPR mappings around the call to
+ cleanup_forwarder_blocks. */
+ start_recording_case_labels ();
+ retval |= cleanup_forwarder_blocks ();
+ end_recording_case_labels ();
+
+#ifdef ENABLE_CHECKING
+ if (retval)
{
- something_changed = cleanup_control_flow ();
- something_changed |= delete_unreachable_blocks ();
- something_changed |= thread_jumps ();
- retval |= something_changed;
+ gcc_assert (!cleanup_control_flow ());
+ gcc_assert (!delete_unreachable_blocks ());
+ gcc_assert (!cleanup_forwarder_blocks ());
}
+#endif
/* Merging the blocks creates no new opportunities for the other
optimizations, so do it here. */
- merge_seq_blocks ();
+ retval |= merge_seq_blocks ();
compact_blocks ();
return label_for_bb[bb->index];
}
-/* Cleanup redundant labels. This is a three-steo process:
+/* Cleanup redundant labels. This is a three-step process:
1) Find the leading label for each block.
2) Redirect all references to labels to the leading labels.
3) Cleanup all useless labels. */
label_for_bb = xcalloc (last_basic_block, sizeof (tree));
/* Find a suitable label for each block. We use the first user-defined
- label is there is one, or otherwise just the first label we see. */
+ label if there is one, or otherwise just the first label we see. */
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
/* Replace all destination labels. */
for (i = 0; i < n; ++i)
- CASE_LABEL (TREE_VEC_ELT (vec, i))
- = main_block_label (CASE_LABEL (TREE_VEC_ELT (vec, i)));
-
+ {
+ tree elt = TREE_VEC_ELT (vec, i);
+ tree label = main_block_label (CASE_LABEL (elt));
+ CASE_LABEL (elt) = label;
+ }
break;
}
tree labels = SWITCH_LABELS (stmt);
int old_size = TREE_VEC_LENGTH (labels);
int i, j, new_size = old_size;
- tree default_label = TREE_VEC_ELT (labels, old_size - 1);
+ tree default_case = TREE_VEC_ELT (labels, old_size - 1);
+ tree default_label;
+
+ /* The default label is always the last case in a switch
+ statement after gimplification. */
+ default_label = CASE_LABEL (default_case);
/* Look for possible opportunities to merge cases.
Ignore the last element of the label vector because it
must be the default case. */
i = 0;
- while (i < old_size - 2)
+ while (i < old_size - 1)
{
tree base_case, base_label, base_high, type;
base_case = TREE_VEC_ELT (labels, i);
{
TREE_VEC_ELT (labels, i) = NULL_TREE;
i++;
+ new_size--;
continue;
}
type = TREE_TYPE (CASE_LOW (base_case));
base_high = CASE_HIGH (base_case) ?
CASE_HIGH (base_case) : CASE_LOW (base_case);
-
+ i++;
/* Try to merge case labels. Break out when we reach the end
of the label vector or when we cannot merge the next case
label with the current one. */
- while (i < old_size - 2)
+ while (i < old_size - 1)
{
- tree merge_case = TREE_VEC_ELT (labels, ++i);
+ tree merge_case = TREE_VEC_ELT (labels, i);
tree merge_label = CASE_LABEL (merge_case);
tree t = int_const_binop (PLUS_EXPR, base_high,
integer_one_node, 1);
CASE_HIGH (base_case) = base_high;
TREE_VEC_ELT (labels, i) = NULL_TREE;
new_size--;
+ i++;
}
else
break;
if (EXPR_HAS_LOCATION (stmt))
{
location_t loc = EXPR_LOCATION (stmt);
- warning ("%Hwill never be executed", &loc);
- return true;
+ if (LOCATION_LINE (loc) > 0)
+ {
+ warning ("%Hwill never be executed", &loc);
+ return true;
+ }
}
switch (TREE_CODE (stmt))
else_has_label = data->has_label;
data->has_label = save_has_label | then_has_label | else_has_label;
- fold_stmt (stmt_p);
then_clause = COND_EXPR_THEN (*stmt_p);
else_clause = COND_EXPR_ELSE (*stmt_p);
- cond = COND_EXPR_COND (*stmt_p);
+ cond = fold (COND_EXPR_COND (*stmt_p));
/* If neither arm does anything at all, we can remove the whole IF. */
if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
}
}
break;
- case SWITCH_EXPR:
+ case ASM_EXPR:
fold_stmt (tp);
data->last_goto = NULL;
break;
/* Remove edges to BB's successors. */
while (EDGE_COUNT (bb->succs) > 0)
- ssa_remove_edge (EDGE_SUCC (bb, 0));
+ remove_edge (EDGE_SUCC (bb, 0));
}
}
/* Remove all the instructions in the block. */
- for (i = bsi_start (bb); !bsi_end_p (i); bsi_remove (&i))
+ for (i = bsi_start (bb); !bsi_end_p (i);)
{
tree stmt = bsi_stmt (i);
- release_defs (stmt);
+ if (TREE_CODE (stmt) == LABEL_EXPR
+ && FORCED_LABEL (LABEL_EXPR_LABEL (stmt)))
+ {
+ basic_block new_bb = bb->prev_bb;
+ block_stmt_iterator new_bsi = bsi_start (new_bb);
+
+ bsi_remove (&i);
+ bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
+ }
+ else
+ {
+ release_defs (stmt);
- set_bb_for_stmt (stmt, NULL);
+ set_bb_for_stmt (stmt, NULL);
+ bsi_remove (&i);
+ }
/* Don't warn for removed gotos. Gotos are often removed due to
jump threading, thus resulting in bogus warnings. Not great,
since this way we lose warnings for gotos in the original
program that are indeed unreachable. */
if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
+ {
+ source_locus t;
+
#ifdef USE_MAPPED_LOCATION
- loc = EXPR_LOCATION (stmt);
+ t = EXPR_LOCATION (stmt);
#else
- loc = EXPR_LOCUS (stmt);
+ t = EXPR_LOCUS (stmt);
#endif
+ if (t && LOCATION_LINE (*t) > 0)
+ loc = t;
+ }
}
/* If requested, give a warning that the first statement in the
remove_phi_nodes_and_edges_for_unreachable_block (bb);
}
-
-/* Examine BB to determine if it is a forwarding block (a block which only
- transfers control to a new destination). If BB is a forwarding block,
- then return the edge leading to the ultimate destination. */
-
-edge
-tree_block_forwards_to (basic_block bb)
-{
- block_stmt_iterator bsi;
- bb_ann_t ann = bb_ann (bb);
- tree stmt;
-
- /* If this block is not forwardable, then avoid useless work. */
- if (! ann->forwardable)
- return NULL;
-
- /* Set this block to not be forwardable. This prevents infinite loops since
- any block currently under examination is considered non-forwardable. */
- ann->forwardable = 0;
-
- /* No forwarding is possible if this block is a special block (ENTRY/EXIT),
- this block has more than one successor, this block's single successor is
- reached via an abnormal edge, this block has phi nodes, or this block's
- single successor has phi nodes. */
- if (bb == EXIT_BLOCK_PTR
- || bb == ENTRY_BLOCK_PTR
- || EDGE_COUNT (bb->succs) != 1
- || EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR
- || (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) != 0
- || phi_nodes (bb)
- || phi_nodes (EDGE_SUCC (bb, 0)->dest))
- return NULL;
-
- /* Walk past any labels at the start of this block. */
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
- {
- stmt = bsi_stmt (bsi);
- if (TREE_CODE (stmt) != LABEL_EXPR)
- break;
- }
-
- /* If we reached the end of this block we may be able to optimize this
- case. */
- if (bsi_end_p (bsi))
- {
- edge dest;
-
- /* Recursive call to pick up chains of forwarding blocks. */
- dest = tree_block_forwards_to (EDGE_SUCC (bb, 0)->dest);
-
- /* If none found, we forward to bb->succs[0] at minimum. */
- if (!dest)
- dest = EDGE_SUCC (bb, 0);
-
- ann->forwardable = 1;
- return dest;
- }
-
- /* No forwarding possible. */
- return NULL;
-}
-
-
/* Try to remove superfluous control structures. */
static bool
{
taken_edge->probability += e->probability;
taken_edge->count += e->count;
- ssa_remove_edge (e);
+ remove_edge (e);
retval = true;
}
else
taken_edge->flags = EDGE_FALLTHRU;
/* We removed some paths from the cfg. */
- if (dom_computed[CDI_DOMINATORS] >= DOM_CONS_OK)
- dom_computed[CDI_DOMINATORS] = DOM_CONS_OK;
+ free_dominance_info (CDI_DOMINATORS);
return retval;
}
-/* Given a control block BB and a predicate VAL, return the edge that
- will be taken out of the block. If VAL does not match a unique
- edge, NULL is returned. */
+/* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
+ predicate VAL, return the edge that will be taken out of the block.
+ If VAL does not match a unique edge, NULL is returned. */
edge
find_taken_edge (basic_block bb, tree val)
gcc_assert (stmt);
gcc_assert (is_ctrl_stmt (stmt));
+ gcc_assert (val);
/* If VAL is a predicate of the form N RELOP N, where N is an
SSA_NAME, we can usually determine its truth value. */
- if (val && COMPARISON_CLASS_P (val))
+ if (COMPARISON_CLASS_P (val))
val = fold (val);
/* If VAL is not a constant, we can't determine which edge might
be taken. */
- if (val == NULL || !really_constant_p (val))
+ if (!really_constant_p (val))
return NULL;
if (TREE_CODE (stmt) == COND_EXPR)
if (TREE_CODE (stmt) == SWITCH_EXPR)
return find_taken_edge_switch_expr (bb, val);
- return EDGE_SUCC (bb, 0);
+ gcc_unreachable ();
}
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
- /* If both edges of the branch lead to the same basic block, it doesn't
- matter which edge is taken. */
- if (true_edge->dest == false_edge->dest)
- return true_edge;
-
/* Otherwise, try to determine which branch of the if() will be taken.
If VAL is a constant but it can't be reduced to a 0 or a 1, then
we don't really know which edge will be taken at runtime. This
static bool
phi_alternatives_equal (basic_block dest, edge e1, edge e2)
{
- tree phi, val1, val2;
- int n1, n2;
+ int n1 = e1->dest_idx;
+ int n2 = e2->dest_idx;
+ tree phi;
for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
{
- n1 = phi_arg_from_edge (phi, e1);
- n2 = phi_arg_from_edge (phi, e2);
-
- gcc_assert (n1 >= 0);
- gcc_assert (n2 >= 0);
+ tree val1 = PHI_ARG_DEF (phi, n1);
+ tree val2 = PHI_ARG_DEF (phi, n2);
- val1 = PHI_ARG_DEF (phi, n1);
- val2 = PHI_ARG_DEF (phi, n2);
+ gcc_assert (val1 != NULL_TREE);
+ gcc_assert (val2 != NULL_TREE);
- if (!operand_equal_p (val1, val2, 0))
+ if (!operand_equal_for_phi_arg_p (val1, val2))
return false;
}
return true;
/* A CALL_EXPR also alters control flow if it does not return. */
- if (call_expr_flags (call) & (ECF_NORETURN | ECF_LONGJMP))
+ if (call_expr_flags (call) & ECF_NORETURN)
return true;
}
from cfg_remove_useless_stmts here since it violates the
invariants for tree--cfg correspondence and thus fits better
here where we do it anyway. */
- FOR_EACH_EDGE (e, ei, bb->succs)
+ e = find_edge (bb, bb->next_bb);
+ if (e)
{
- if (e->dest != bb->next_bb)
- continue;
-
if (e->flags & EDGE_TRUE_VALUE)
COND_EXPR_THEN (stmt) = build_empty_stmt ();
else if (e->flags & EDGE_FALSE_VALUE)
/* Finds iterator for STMT. */
extern block_stmt_iterator
-stmt_for_bsi (tree stmt)
+bsi_for_stmt (tree stmt)
{
block_stmt_iterator bsi;
The requirement for no PHI nodes could be relaxed. Basically we
would have to examine the PHIs to prove that none of them used
- the value set by the statement we want to insert on E. That
+ the value set by the statement we want to insert on E. That
hardly seems worth the effort. */
if (EDGE_COUNT (dest->preds) == 1
&& ! phi_nodes (dest)
/* This routine will commit all pending edge insertions, creating any new
- basic blocks which are necessary.
-
- If specified, NEW_BLOCKS returns a count of the number of new basic
- blocks which were created. */
+ basic blocks which are necessary. */
void
-bsi_commit_edge_inserts (int *new_blocks)
+bsi_commit_edge_inserts (void)
{
basic_block bb;
edge e;
- int blocks;
edge_iterator ei;
- blocks = n_basic_blocks;
-
- bsi_commit_edge_inserts_1 (EDGE_SUCC (ENTRY_BLOCK_PTR, 0));
+ bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR, 0), NULL);
FOR_EACH_BB (bb)
FOR_EACH_EDGE (e, ei, bb->succs)
- bsi_commit_edge_inserts_1 (e);
-
- if (new_blocks)
- *new_blocks = n_basic_blocks - blocks;
+ bsi_commit_one_edge_insert (e, NULL);
}
-/* Commit insertions pending at edge E. */
+/* Commit insertions pending at edge E. If a new block is created, set NEW_BB
+ to this block, otherwise set it to NULL. */
-static void
-bsi_commit_edge_inserts_1 (edge e)
+void
+bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
{
+ if (new_bb)
+ *new_bb = NULL;
if (PENDING_STMT (e))
{
block_stmt_iterator bsi;
PENDING_STMT (e) = NULL_TREE;
- if (tree_find_edge_insert_loc (e, &bsi, NULL))
+ if (tree_find_edge_insert_loc (e, &bsi, new_bb))
bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
else
bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
append_to_statement_list (stmt, &PENDING_STMT (e));
}
-/* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If new block has to
- be created, it is returned. */
+/* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
+ block has to be created, it is returned. */
basic_block
bsi_insert_on_edge_immediate (edge e, tree stmt)
Tree specific functions for CFG manipulation
---------------------------------------------------------------------------*/
+/* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
+
+static void
+reinstall_phi_args (edge new_edge, edge old_edge)
+{
+ tree var, phi;
+
+ if (!PENDING_STMT (old_edge))
+ return;
+
+ for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
+ var && phi;
+ var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
+ {
+ tree result = TREE_PURPOSE (var);
+ tree arg = TREE_VALUE (var);
+
+ gcc_assert (result == PHI_RESULT (phi));
+
+ add_phi_arg (phi, arg, new_edge);
+ }
+
+ PENDING_STMT (old_edge) = NULL;
+}
+
/* Split a (typically critical) edge EDGE_IN. Return the new block.
Abort on abnormal edges. */
{
basic_block new_bb, after_bb, dest, src;
edge new_edge, e;
- tree phi;
- int i, num_elem;
- edge_iterator ei;
/* Abnormal edges cannot be split. */
gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
/* Place the new block in the block list. Try to keep the new block
near its "logical" location. This is of most help to humans looking
at debugging dumps. */
- FOR_EACH_EDGE (e, ei, dest->preds)
- if (e->src->next_bb == dest)
- break;
- if (!e)
- after_bb = dest->prev_bb;
- else
+ if (dest->prev_bb && find_edge (dest->prev_bb, dest))
after_bb = edge_in->src;
+ else
+ after_bb = dest->prev_bb;
new_bb = create_empty_bb (after_bb);
new_bb->frequency = EDGE_FREQUENCY (edge_in);
new_edge->probability = REG_BR_PROB_BASE;
new_edge->count = edge_in->count;
- /* Find all the PHI arguments on the original edge, and change them to
- the new edge. Do it before redirection, so that the argument does not
- get removed. */
- for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
- {
- num_elem = PHI_NUM_ARGS (phi);
- for (i = 0; i < num_elem; i++)
- if (PHI_ARG_EDGE (phi, i) == edge_in)
- {
- PHI_ARG_EDGE (phi, i) = new_edge;
- break;
- }
- }
-
e = redirect_edge_and_branch (edge_in, new_bb);
gcc_assert (e);
- gcc_assert (!PENDING_STMT (edge_in));
+ reinstall_phi_args (new_edge, e);
return new_bb;
}
tree) and ensure that any variable used as a prefix is marked
addressable. */
for (x = TREE_OPERAND (t, 0);
- (handled_component_p (x)
- || TREE_CODE (x) == REALPART_EXPR
- || TREE_CODE (x) == IMAGPART_EXPR);
+ handled_component_p (x);
x = TREE_OPERAND (x, 0))
;
break;
case COND_EXPR:
- x = TREE_OPERAND (t, 0);
+ x = COND_EXPR_COND (t);
if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
{
error ("non-boolean used in condition");
that determine where to reference is either a constant or a variable,
verify that the base is valid, and then show we've already checked
the subtrees. */
- while (TREE_CODE (t) == REALPART_EXPR || TREE_CODE (t) == IMAGPART_EXPR
- || handled_component_p (t))
+ while (handled_component_p (t))
{
if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
CHECK_OP (2, "Invalid COMPONENT_REF offset operator");
gimple invariants if they overflowed. */
|| CONSTANT_CLASS_P (t)
|| is_gimple_min_invariant (t)
- || TREE_CODE (t) == SSA_NAME)
+ || TREE_CODE (t) == SSA_NAME
+ || t == error_mark_node)
+ return true;
+
+ if (TREE_CODE (t) == CASE_LABEL_EXPR)
return true;
while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
if (label_to_block (LABEL_EXPR_LABEL (bsi_stmt (bsi))) != bb)
{
+ tree stmt = bsi_stmt (bsi);
error ("Label %s to block does not match in bb %d\n",
- IDENTIFIER_POINTER (DECL_NAME (bsi_stmt (bsi))),
+ IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))),
bb->index);
err = 1;
}
if (decl_function_context (LABEL_EXPR_LABEL (bsi_stmt (bsi)))
!= current_function_decl)
{
+ tree stmt = bsi_stmt (bsi);
error ("Label %s has incorrect context in bb %d\n",
- IDENTIFIER_POINTER (DECL_NAME (bsi_stmt (bsi))),
+ IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))),
bb->index);
err = 1;
}
if (label_bb->aux != (void *)2)
{
- error ("Missing edge %i->%i\n",
+ error ("Missing edge %i->%i",
bb->index, label_bb->index);
err = 1;
}
}
-/* Updates phi nodes after creating forwarder block joined
+/* Updates phi nodes after creating a forwarder block joined
by edge FALLTHRU. */
static void
edge e;
edge_iterator ei;
basic_block dummy, bb;
- tree phi, new_phi, var, prev, next;
+ tree phi, new_phi, var;
dummy = fallthru->src;
bb = fallthru->dest;
new_phi = create_phi_node (var, bb);
SSA_NAME_DEF_STMT (var) = new_phi;
SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
- add_phi_arg (&new_phi, PHI_RESULT (phi), fallthru);
+ add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
}
/* Ensure that the PHI node chain is in the same order. */
- prev = NULL;
- for (phi = phi_nodes (bb); phi; phi = next)
- {
- next = PHI_CHAIN (phi);
- PHI_CHAIN (phi) = prev;
- prev = phi;
- }
- set_phi_nodes (bb, prev);
+ set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
/* Add the arguments we have stored on edges. */
FOR_EACH_EDGE (e, ei, bb->preds)
if (e == fallthru)
continue;
- for (phi = phi_nodes (bb), var = PENDING_STMT (e);
- phi;
- phi = PHI_CHAIN (phi), var = TREE_CHAIN (var))
- add_phi_arg (&phi, TREE_VALUE (var), e);
-
- PENDING_STMT (e) = NULL;
+ flush_pending_stmts (e);
}
}
/* Return true if basic block BB does nothing except pass control
flow to another block and that we can safely insert a label at
- the start of the successor block. */
+ the start of the successor block.
+
+ As a precondition, we require that BB be not equal to
+ ENTRY_BLOCK_PTR. */
static bool
tree_forwarder_block_p (basic_block bb)
{
block_stmt_iterator bsi;
- edge e;
- edge_iterator ei;
-
- /* If we have already determined that this block is not forwardable,
- then no further checks are necessary. */
- if (! bb_ann (bb)->forwardable)
- return false;
- /* BB must have a single outgoing normal edge. Otherwise it can not be
- a forwarder block. */
+ /* BB must have a single outgoing edge. */
if (EDGE_COUNT (bb->succs) != 1
+ /* BB can not have any PHI nodes. This could potentially be
+ relaxed early in compilation if we re-rewrote the variables
+ appearing in any PHI nodes in forwarder blocks. */
+ || phi_nodes (bb)
+ /* BB may not be a predecessor of EXIT_BLOCK_PTR. */
|| EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR
- || (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL)
- || bb == ENTRY_BLOCK_PTR)
- {
- bb_ann (bb)->forwardable = 0;
- return false;
- }
-
- /* Successors of the entry block are not forwarders. */
- FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
- if (e->dest == bb)
- {
- bb_ann (bb)->forwardable = 0;
- return false;
- }
-
- /* BB can not have any PHI nodes. This could potentially be relaxed
- early in compilation if we re-rewrote the variables appearing in
- any PHI nodes in forwarder blocks. */
- if (phi_nodes (bb))
- {
- bb_ann (bb)->forwardable = 0;
- return false;
- }
+ /* Nor should this be an infinite loop. */
+ || EDGE_SUCC (bb, 0)->dest == bb
+ /* BB may not have an abnormal outgoing edge. */
+ || (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL))
+ return false;
+
+#if ENABLE_CHECKING
+ gcc_assert (bb != ENTRY_BLOCK_PTR);
+#endif
/* Now walk through the statements. We can ignore labels, anything else
means this is not a forwarder block. */
break;
default:
- bb_ann (bb)->forwardable = 0;
return false;
}
}
+ if (find_edge (ENTRY_BLOCK_PTR, bb))
+ return false;
+
return true;
}
+/* Return true if BB has at least one abnormal incoming edge. */
-/* Thread jumps over empty statements.
-
- This code should _not_ thread over obviously equivalent conditions
- as that requires nontrivial updates to the SSA graph. */
-
-static bool
-thread_jumps (void)
+static inline bool
+has_abnormal_incoming_edge_p (basic_block bb)
{
- edge e, last, old;
- basic_block bb, dest, tmp, old_dest, curr, dom;
- tree phi;
- int arg;
- bool retval = false;
-
- FOR_EACH_BB (bb)
- bb_ann (bb)->forwardable = 1;
+ edge e;
+ edge_iterator ei;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
- {
- edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ return true;
- /* Don't waste time on unreachable blocks. */
- if (EDGE_COUNT (bb->preds) == 0)
- continue;
+ return false;
+}
- /* Nor on forwarders. */
- if (tree_forwarder_block_p (bb))
- continue;
-
- /* This block is now part of a forwarding path, mark it as not
- forwardable so that we can detect loops. This bit will be
- reset below. */
- bb_ann (bb)->forwardable = 0;
+/* Removes forwarder block BB. Returns false if this failed. If a new
+ forwarder block is created due to redirection of edges, it is
+ stored to worklist. */
- /* Examine each of our block's successors to see if it is
- forwardable. */
- for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
- {
- int freq;
- gcov_type count;
+static bool
+remove_forwarder_block (basic_block bb, basic_block **worklist)
+{
+ edge succ = EDGE_SUCC (bb, 0), e, s;
+ basic_block dest = succ->dest;
+ tree label;
+ tree phi;
+ edge_iterator ei;
+ block_stmt_iterator bsi, bsi_to;
+ bool seen_abnormal_edge = false;
- /* If the edge is abnormal or its destination is not
- forwardable, then there's nothing to do. */
- if ((e->flags & EDGE_ABNORMAL)
- || !tree_forwarder_block_p (e->dest))
- {
- ei_next (&ei);
- continue;
- }
+ /* We check for infinite loops already in tree_forwarder_block_p.
+ However it may happen that the infinite loop is created
+ afterwards due to removal of forwarders. */
+ if (dest == bb)
+ return false;
- count = e->count;
- freq = EDGE_FREQUENCY (e);
-
- /* Now walk through as many forwarder blocks as possible to
- find the ultimate destination we want to thread our jump
- to. */
- last = EDGE_SUCC (e->dest, 0);
- bb_ann (e->dest)->forwardable = 0;
- for (dest = EDGE_SUCC (e->dest, 0)->dest;
- tree_forwarder_block_p (dest);
- last = EDGE_SUCC (dest, 0),
- dest = EDGE_SUCC (dest, 0)->dest)
- {
- /* An infinite loop detected. We redirect the edge anyway, so
- that the loop is shrunk into single basic block. */
- if (!bb_ann (dest)->forwardable)
- break;
+ /* If the destination block consists of an nonlocal label, do not merge
+ it. */
+ label = first_stmt (bb);
+ if (label
+ && TREE_CODE (label) == LABEL_EXPR
+ && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+ return false;
- if (EDGE_SUCC (dest, 0)->dest == EXIT_BLOCK_PTR)
- break;
+ /* If there is an abnormal edge to basic block BB, but not into
+ dest, problems might occur during removal of the phi node at out
+ of ssa due to overlapping live ranges of registers.
+
+ If there is an abnormal edge in DEST, the problems would occur
+ anyway since cleanup_dead_labels would then merge the labels for
+ two different eh regions, and rest of exception handling code
+ does not like it.
+
+ So if there is an abnormal edge to BB, proceed only if there is
+ no abnormal edge to DEST and there are no phi nodes in DEST. */
+ if (has_abnormal_incoming_edge_p (bb))
+ {
+ seen_abnormal_edge = true;
- bb_ann (dest)->forwardable = 0;
- }
+ if (has_abnormal_incoming_edge_p (dest)
+ || phi_nodes (dest) != NULL_TREE)
+ return false;
+ }
- /* Reset the forwardable marks to 1. */
- for (tmp = e->dest;
- tmp != dest;
- tmp = EDGE_SUCC (tmp, 0)->dest)
- bb_ann (tmp)->forwardable = 1;
+ /* If there are phi nodes in DEST, and some of the blocks that are
+ predecessors of BB are also predecessors of DEST, check that the
+ phi node arguments match. */
+ if (phi_nodes (dest))
+ {
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ s = find_edge (e->src, dest);
+ if (!s)
+ continue;
- if (dest == e->dest)
- {
- ei_next (&ei);
- continue;
- }
-
- old = find_edge (bb, dest);
- if (old)
- {
- /* If there already is an edge, check whether the values
- in phi nodes differ. */
- if (!phi_alternatives_equal (dest, last, old))
- {
- /* The previous block is forwarder. Redirect our jump
- to that target instead since we know it has no PHI
- nodes that will need updating. */
- dest = last->src;
-
- /* That might mean that no forwarding at all is possible. */
- if (dest == e->dest)
- {
- ei_next (&ei);
- continue;
- }
+ if (!phi_alternatives_equal (dest, succ, s))
+ return false;
+ }
+ }
- old = find_edge (bb, dest);
- }
- }
+ /* Redirect the edges. */
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
+ {
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ /* If there is an abnormal edge, redirect it anyway, and
+ move the labels to the new block to make it legal. */
+ s = redirect_edge_succ_nodup (e, dest);
+ }
+ else
+ s = redirect_edge_and_branch (e, dest);
- /* Perform the redirection. */
- retval = true;
- old_dest = e->dest;
- e = redirect_edge_and_branch (e, dest);
+ if (s == e)
+ {
+ /* Create arguments for the phi nodes, since the edge was not
+ here before. */
+ for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
+ add_phi_arg (phi, PHI_ARG_DEF (phi, succ->dest_idx), s);
+ }
+ else
+ {
+ /* The source basic block might become a forwarder. We know
+ that it was not a forwarder before, since it used to have
+ at least two outgoing edges, so we may just add it to
+ worklist. */
+ if (tree_forwarder_block_p (s->src))
+ *(*worklist)++ = s->src;
+ }
+ }
- /* Update the profile. */
- if (profile_status != PROFILE_ABSENT)
- for (curr = old_dest; curr != dest; curr = EDGE_SUCC (curr, 0)->dest)
- {
- curr->frequency -= freq;
- if (curr->frequency < 0)
- curr->frequency = 0;
- curr->count -= count;
- if (curr->count < 0)
- curr->count = 0;
- EDGE_SUCC (curr, 0)->count -= count;
- if (EDGE_SUCC (curr, 0)->count < 0)
- EDGE_SUCC (curr, 0)->count = 0;
- }
+ if (seen_abnormal_edge)
+ {
+ /* Move the labels to the new block, so that the redirection of
+ the abnormal edges works. */
- if (!old)
- {
- /* Update PHI nodes. We know that the new argument should
- have the same value as the argument associated with LAST.
- Otherwise we would have changed our target block above. */
- for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
- {
- arg = phi_arg_from_edge (phi, last);
- gcc_assert (arg >= 0);
- add_phi_arg (&phi, PHI_ARG_DEF (phi, arg), e);
- }
- }
+ bsi_to = bsi_start (dest);
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
+ {
+ label = bsi_stmt (bsi);
+ gcc_assert (TREE_CODE (label) == LABEL_EXPR);
+ bsi_remove (&bsi);
+ bsi_insert_before (&bsi_to, label, BSI_CONTINUE_LINKING);
+ }
+ }
- /* Update the dominators. */
- if (dom_computed[CDI_DOMINATORS] >= DOM_CONS_OK)
- {
- /* Remove the unreachable blocks (observe that if all blocks
- were reachable before, only those in the path we threaded
- over and did not have any predecessor outside of the path
- become unreachable). */
- for (; old_dest != dest; old_dest = tmp)
- {
- tmp = EDGE_SUCC (old_dest, 0)->dest;
+ /* Update the dominators. */
+ if (dom_info_available_p (CDI_DOMINATORS))
+ {
+ basic_block dom, dombb, domdest;
- if (EDGE_COUNT (old_dest->preds) > 0)
- break;
+ dombb = get_immediate_dominator (CDI_DOMINATORS, bb);
+ domdest = get_immediate_dominator (CDI_DOMINATORS, dest);
+ if (domdest == bb)
+ {
+ /* Shortcut to avoid calling (relatively expensive)
+ nearest_common_dominator unless necessary. */
+ dom = dombb;
+ }
+ else
+ dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb);
- delete_basic_block (old_dest);
- }
- /* If the dominator of the destination was in the path, set its
- dominator to the start of the redirected edge. */
- if (get_immediate_dominator (CDI_DOMINATORS, old_dest) == NULL)
- set_immediate_dominator (CDI_DOMINATORS, old_dest, bb);
+ set_immediate_dominator (CDI_DOMINATORS, dest, dom);
+ }
- /* Now proceed like if we forwarded just over one edge at a time.
- Algorithm for forwarding edge S --> A over edge A --> B then
- is
+ /* And kill the forwarder block. */
+ delete_basic_block (bb);
- if (idom (B) == A
- && !dominated_by (S, B))
- idom (B) = idom (A);
- recount_idom (A); */
+ return true;
+}
- for (; old_dest != dest; old_dest = tmp)
- {
- tmp = EDGE_SUCC (old_dest, 0)->dest;
+/* Removes forwarder blocks. */
- if (get_immediate_dominator (CDI_DOMINATORS, tmp) == old_dest
- && !dominated_by_p (CDI_DOMINATORS, bb, tmp))
- {
- dom = get_immediate_dominator (CDI_DOMINATORS, old_dest);
- set_immediate_dominator (CDI_DOMINATORS, tmp, dom);
- }
+static bool
+cleanup_forwarder_blocks (void)
+{
+ basic_block bb;
+ bool changed = false;
+ basic_block *worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+ basic_block *current = worklist;
- dom = recount_dominator (CDI_DOMINATORS, old_dest);
- set_immediate_dominator (CDI_DOMINATORS, old_dest, dom);
- }
- }
- }
+ FOR_EACH_BB (bb)
+ {
+ if (tree_forwarder_block_p (bb))
+ *current++ = bb;
+ }
- /* Reset the forwardable bit on our block since it's no longer in
- a forwarding chain path. */
- bb_ann (bb)->forwardable = 1;
+ while (current != worklist)
+ {
+ bb = *--current;
+ changed |= remove_forwarder_block (bb, ¤t);
}
- return retval;
+ free (worklist);
+ return changed;
}
-
/* Return a non-special label in the head of basic block BLOCK.
Create one if it doesn't exist. */
tree_try_redirect_by_replacing_jump (edge e, basic_block target)
{
basic_block src = e->src;
- edge tmp;
block_stmt_iterator b;
tree stmt;
- edge_iterator ei;
- /* Verify that all targets will be TARGET. */
- FOR_EACH_EDGE (tmp, ei, src->succs)
- if (tmp->dest != target && tmp != e)
- break;
-
- if (tmp)
+ /* We can replace or remove a complex jump only when we have exactly
+ two edges. */
+ if (EDGE_COUNT (src->succs) != 2
+ /* Verify that all targets will be TARGET. Specifically, the
+ edge that is not E must also go to TARGET. */
+ || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
return NULL;
b = bsi_last (src);
case SWITCH_EXPR:
{
- tree vec = SWITCH_LABELS (stmt);
- size_t i, n = TREE_VEC_LENGTH (vec);
+ tree cases = get_cases_for_edge (e, stmt);
- for (i = 0; i < n; ++i)
+ /* If we have a list of cases associated with E, then use it
+ as it's a lot faster than walking the entire case vector. */
+ if (cases)
{
- tree elt = TREE_VEC_ELT (vec, i);
- if (label_to_block (CASE_LABEL (elt)) == e->dest)
- CASE_LABEL (elt) = label;
+ edge e2 = find_edge (e->src, dest);
+ tree last, first;
+
+ first = cases;
+ while (cases)
+ {
+ last = cases;
+ CASE_LABEL (cases) = label;
+ cases = TREE_CHAIN (cases);
+ }
+
+ /* If there was already an edge in the CFG, then we need
+ to move all the cases associated with E to E2. */
+ if (e2)
+ {
+ tree cases2 = get_cases_for_edge (e2, stmt);
+
+ TREE_CHAIN (last) = TREE_CHAIN (cases2);
+ TREE_CHAIN (cases2) = first;
+ }
+ }
+ else
+ {
+ tree vec = SWITCH_LABELS (stmt);
+ size_t i, n = TREE_VEC_LENGTH (vec);
+
+ for (i = 0; i < n; i++)
+ {
+ tree elt = TREE_VEC_ELT (vec, i);
+
+ if (label_to_block (CASE_LABEL (elt)) == e->dest)
+ CASE_LABEL (elt) = label;
+ }
}
+
+ break;
}
- break;
case RETURN_EXPR:
bsi_remove (&bsi);
/* First copy the phi nodes. We do not copy phi node arguments here,
since the edges are not ready yet. Keep the chain of phi nodes in
the same order, so that we can add them later. */
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
mark_for_rewrite (PHI_RESULT (phi));
create_phi_node (PHI_RESULT (phi), new_bb);
}
- set_phi_nodes (new_bb, nreverse (phi_nodes (new_bb)));
+ set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
bsi_tgt = bsi_start (new_bb);
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
phi;
- phi = phi_next, phi_copy = TREE_CHAIN (phi_copy))
+ phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
{
- phi_next = TREE_CHAIN (phi);
+ phi_next = PHI_CHAIN (phi);
gcc_assert (PHI_RESULT (phi) == PHI_RESULT (phi_copy));
def = PHI_ARG_DEF_FROM_EDGE (phi, e);
- add_phi_arg (&phi_copy, def, e_copy);
+ add_phi_arg (phi_copy, def, e_copy);
}
}
}
if (e->flags & EDGE_ABNORMAL)
break;
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
rewrite_to_new_ssa_names_def (PHI_RESULT_PTR (phi), phi, map);
if (e)
v_must_defs = V_MUST_DEF_OPS (ann);
for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
- rewrite_to_new_ssa_names_def
- (V_MUST_DEF_OP_PTR (v_must_defs, i), stmt, map);
+ {
+ rewrite_to_new_ssa_names_def
+ (V_MUST_DEF_RESULT_PTR (v_must_defs, i), stmt, map);
+ rewrite_to_new_ssa_names_use
+ (V_MUST_DEF_KILL_PTR (v_must_defs, i), map);
+ }
}
FOR_EACH_EDGE (e, ei, bb->succs)
- for (phi = phi_nodes (e->dest); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
{
rewrite_to_new_ssa_names_use
(PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), map);
struct loop *loop = entry->dest->loop_father;
edge exit_copy;
bitmap definitions;
- tree phi, var;
+ tree phi;
basic_block *doms;
htab_t ssa_name_map = NULL;
edge redirected;
/* Redirect the entry and add the phi node arguments. */
redirected = redirect_edge_and_branch (entry, entry->dest->rbi->copy);
gcc_assert (redirected != NULL);
- for (phi = phi_nodes (entry->dest), var = PENDING_STMT (entry);
- phi;
- phi = TREE_CHAIN (phi), var = TREE_CHAIN (var))
- add_phi_arg (&phi, TREE_VALUE (var), entry);
- PENDING_STMT (entry) = NULL;
+ flush_pending_stmts (entry);
/* Concerning updating of dominators: We must recount dominators
for entry block and its copy. Anything that is outside of the region, but
tree name = ssa_name (ver);
phi = create_phi_node (name, exit->dest);
- add_phi_arg (&phi, name, exit);
- add_phi_arg (&phi, name, exit_copy);
+ add_phi_arg (phi, name, exit);
+ add_phi_arg (phi, name, exit_copy);
SSA_NAME_DEF_STMT (name) = phi;
}
leads to different results from -fbranch-probabilities. */
call = get_call_expr_in (t);
if (call
- && !(call_expr_flags (call) &
- (ECF_NORETURN | ECF_LONGJMP | ECF_ALWAYS_RETURN)))
+ && !(call_expr_flags (call) & (ECF_NORETURN | ECF_ALWAYS_RETURN)))
return true;
if (TREE_CODE (t) == ASM_EXPR
Handle this by adding a dummy instruction in a new last basic block. */
if (check_last_block)
{
- edge_iterator ei;
basic_block bb = EXIT_BLOCK_PTR->prev_bb;
block_stmt_iterator bsi = bsi_last (bb);
tree t = NULL_TREE;
{
edge e;
- FOR_EACH_EDGE (e, ei, bb->succs)
- if (e->dest == EXIT_BLOCK_PTR)
- {
- bsi_insert_on_edge (e, build_empty_stmt ());
- bsi_commit_edge_inserts ((int *)NULL);
- break;
- }
+ e = find_edge (bb, EXIT_BLOCK_PTR);
+ if (e)
+ {
+ bsi_insert_on_edge (e, build_empty_stmt ());
+ bsi_commit_edge_inserts ();
+ }
}
}
#ifdef ENABLE_CHECKING
if (stmt == last_stmt)
{
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->succs)
- gcc_assert (e->dest != EXIT_BLOCK_PTR);
+ e = find_edge (bb, EXIT_BLOCK_PTR);
+ gcc_assert (e == NULL);
}
#endif
{
if (e->flags & EDGE_EH)
{
- ssa_remove_edge (e);
+ remove_edge (e);
changed = true;
}
else
ei_next (&ei);
}
+ /* Removal of dead EH edges might change dominators of not
+ just immediate successors. E.g. when bb1 is changed so that
+ it no longer can throw and bb1->bb3 and bb1->bb4 are dead
+ eh edges purged by this function in:
+ 0
+ / \
+ v v
+ 1-->2
+ / \ |
+ v v |
+ 3-->4 |
+ \ v
+ --->5
+ |
+ -
+ idom(bb5) must be recomputed. For now just free the dominance
+ info. */
+ if (changed)
+ free_dominance_info (CDI_DOMINATORS);
+
return changed;
}
tree_purge_all_dead_eh_edges (bitmap blocks)
{
bool changed = false;
- size_t i;
+ unsigned i;
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
return changed;
}
+/* This function is called whenever a new edge is created or
+ redirected. */
+
+static void
+tree_execute_on_growing_pred (edge e)
+{
+ basic_block bb = e->dest;
+
+ if (phi_nodes (bb))
+ reserve_phi_args_for_new_edge (bb);
+}
+
+/* This function is called immediately before edge E is removed from
+ the edge vector E->dest->preds. */
+
+static void
+tree_execute_on_shrinking_pred (edge e)
+{
+ if (phi_nodes (e->dest))
+ remove_phi_args (e);
+}
+
struct cfg_hooks tree_cfg_hooks = {
"tree",
tree_verify_flow_info,
NULL, /* tidy_fallthru_edge */
tree_block_ends_with_call_p, /* block_ends_with_call_p */
tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
- tree_flow_call_edges_add /* flow_call_edges_add */
+ tree_flow_call_edges_add, /* flow_call_edges_add */
+ tree_execute_on_growing_pred, /* execute_on_growing_pred */
+ tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
};
edge e;
edge_iterator ei;
+ /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
+ expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
+ mappings around the calls to split_edge. */
+ start_recording_case_labels ();
FOR_ALL_BB (bb)
{
FOR_EACH_EDGE (e, ei, bb->succs)
split_edge (e);
}
}
+ end_recording_case_labels ();
}
struct tree_opt_pass pass_split_crit_edges =
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