/* 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 "toplev.h"
#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 edge tree_redirect_edge_and_branch (edge, basic_block);
static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
static void split_critical_edges (void);
+static bool remove_fallthru_edge (VEC(edge) *);
/* Various helpers. */
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 bool tree_forwarder_block_p (basic_block, bool);
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);
/* Finally, if no edges were created above, this is a regular
basic block that only needs a fallthru edge. */
- if (bb->succ == NULL)
+ if (EDGE_COUNT (bb->succs) == 0)
make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
}
case RESX_EXPR:
make_eh_edges (last);
/* Yet another NORETURN hack. */
- if (bb->succ == NULL)
+ if (EDGE_COUNT (bb->succs) == 0)
make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
break;
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)
{
}
/* Degenerate case of computed goto with no labels. */
- if (!for_call && !bb->succ)
+ if (!for_call && EDGE_COUNT (bb->succs) == 0)
make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
}
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;
tree stmt;
block_stmt_iterator bsi;
- if (!a->succ
- || a->succ->succ_next)
+ if (EDGE_COUNT (a->succs) != 1)
+ return false;
+
+ if (EDGE_SUCC (a, 0)->flags & EDGE_ABNORMAL)
return false;
- if (a->succ->flags & EDGE_ABNORMAL)
+ if (EDGE_SUCC (a, 0)->dest != b)
return false;
- if (a->succ->dest != b)
+ if (EDGE_COUNT (b->preds) > 1)
return false;
if (b == EXIT_BLOCK_PTR)
return false;
- if (b->pred->pred_next)
- return false;
-
/* If A ends by a statement causing exceptions or something similar, we
cannot merge the blocks. */
stmt = last_stmt (a);
/* Ensure that B follows A. */
move_block_after (b, a);
- gcc_assert (a->succ->flags & EDGE_FALLTHRU);
+ gcc_assert (EDGE_SUCC (a, 0)->flags & EDGE_FALLTHRU);
gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
/* Remove labels from B and set bb_for_stmt to A for other statements. */
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;
/* Check whether we come here from a condition, and if so, get the
condition. */
- if (!bb->pred
- || bb->pred->pred_next
- || !(bb->pred->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
+ if (EDGE_COUNT (bb->preds) != 1
+ || !(EDGE_PRED (bb, 0)->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
return;
- cond = COND_EXPR_COND (last_stmt (bb->pred->src));
+ cond = COND_EXPR_COND (last_stmt (EDGE_PRED (bb, 0)->src));
if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
{
var = cond;
- val = (bb->pred->flags & EDGE_FALSE_VALUE
+ val = (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE
? boolean_false_node : boolean_true_node);
}
else if (TREE_CODE (cond) == TRUTH_NOT_EXPR
|| TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL))
{
var = TREE_OPERAND (cond, 0);
- val = (bb->pred->flags & EDGE_FALSE_VALUE
+ val = (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE
? boolean_true_node : boolean_false_node);
}
else
{
- if (bb->pred->flags & EDGE_FALSE_VALUE)
+ if (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE)
cond = invert_truthvalue (cond);
if (TREE_CODE (cond) == EQ_EXPR
&& (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
}
/* Remove edges to BB's successors. */
- while (bb->succ != NULL)
- ssa_remove_edge (bb->succ);
+ while (EDGE_COUNT (bb->succs) > 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);
+ 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
- || !bb->succ
- || bb->succ->succ_next
- || bb->succ->dest == EXIT_BLOCK_PTR
- || (bb->succ->flags & EDGE_ABNORMAL) != 0
- || phi_nodes (bb)
- || phi_nodes (bb->succ->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 (bb->succ->dest);
-
- /* If none found, we forward to bb->succ at minimum. */
- if (!dest)
- dest = bb->succ;
-
- ann->forwardable = 1;
- return dest;
- }
-
- /* No forwarding possible. */
- return NULL;
-}
-
-
/* Try to remove superfluous control structures. */
static bool
basic_block bb;
block_stmt_iterator bsi;
bool retval = false;
- tree stmt;
+ tree stmt, call;
FOR_EACH_BB (bb)
{
if (TREE_CODE (stmt) == COND_EXPR
|| TREE_CODE (stmt) == SWITCH_EXPR)
retval |= cleanup_control_expr_graph (bb, bsi);
+
+ /* Check for indirect calls that have been turned into
+ noreturn calls. */
+ call = get_call_expr_in (stmt);
+ if (call != 0
+ && (call_expr_flags (call) & ECF_NORETURN) != 0
+ && remove_fallthru_edge (bb->succs))
+ {
+ free_dominance_info (CDI_DOMINATORS);
+ retval = true;
+ }
}
return retval;
}
bool retval = false;
tree expr = bsi_stmt (bsi), val;
- if (bb->succ->succ_next)
+ if (EDGE_COUNT (bb->succs) > 1)
{
- edge e, next;
+ edge e;
+ edge_iterator ei;
switch (TREE_CODE (expr))
{
return false;
/* Remove all the edges except the one that is always executed. */
- for (e = bb->succ; e; e = next)
+ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
- next = e->succ_next;
if (e != taken_edge)
{
taken_edge->probability += e->probability;
taken_edge->count += e->count;
- ssa_remove_edge (e);
+ remove_edge (e);
retval = true;
}
+ else
+ ei_next (&ei);
}
if (taken_edge->probability > REG_BR_PROB_BASE)
taken_edge->probability = REG_BR_PROB_BASE;
}
else
- taken_edge = bb->succ;
+ taken_edge = EDGE_SUCC (bb, 0);
bsi_remove (&bsi);
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;
}
+/* Remove any fallthru edge from EV. Return true if an edge was removed. */
+
+static bool
+remove_fallthru_edge (VEC(edge) *ev)
+{
+ edge_iterator ei;
+ edge e;
+
+ FOR_EACH_EDGE (e, ei, ev)
+ if ((e->flags & EDGE_FALLTHRU) != 0)
+ {
+ remove_edge (e);
+ return true;
+ }
+ return false;
+}
-/* 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 always determine its truth value (except when
- doing floating point comparisons that may involve NaNs). */
- if (val
- && TREE_CODE_CLASS (TREE_CODE (val)) == '<'
- && TREE_OPERAND (val, 0) == TREE_OPERAND (val, 1)
- && TREE_CODE (TREE_OPERAND (val, 0)) == SSA_NAME
- && (TREE_CODE (TREE_TYPE (TREE_OPERAND (val, 0))) != REAL_TYPE
- || !HONOR_NANS (TYPE_MODE (TREE_TYPE (TREE_OPERAND (val, 0))))))
- {
- enum tree_code code = TREE_CODE (val);
-
- if (code == EQ_EXPR || code == LE_EXPR || code == GE_EXPR)
- val = boolean_true_node;
- else if (code == LT_EXPR || code == GT_EXPR || code == NE_EXPR)
- val = boolean_false_node;
- }
+ SSA_NAME, we can usually determine its truth value. */
+ 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 bb->succ;
+ 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);
+ tree val1 = PHI_ARG_DEF (phi, n1);
+ tree val2 = PHI_ARG_DEF (phi, n2);
- gcc_assert (n1 >= 0);
- gcc_assert (n2 >= 0);
+ gcc_assert (val1 != NULL_TREE);
+ gcc_assert (val2 != NULL_TREE);
- val1 = PHI_ARG_DEF (phi, n1);
- val2 = PHI_ARG_DEF (phi, n2);
-
- if (!operand_equal_p (val1, val2, 0))
+ if (!operand_equal_for_phi_arg_p (val1, val2))
return false;
}
n_edges = 0;
FOR_EACH_BB (bb)
- {
- edge e;
- for (e = bb->succ; e; e = e->succ_next)
- n_edges++;
- }
+ n_edges += EDGE_COUNT (bb->succs);
size = n_edges * sizeof (struct edge_def);
total += size;
fprintf (file, fmt_str_1, "Edges", n_edges, SCALE (size), LABEL (size));
tree_cfg2vcg (FILE *file)
{
edge e;
+ edge_iterator ei;
basic_block bb;
const char *funcname
= lang_hooks.decl_printable_name (current_function_decl, 2);
fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
/* Write blocks and edges. */
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
{
fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
e->dest->index);
bb->index, bb->index, head_name, head_line, end_name,
end_line);
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (e->dest == EXIT_BLOCK_PTR)
fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
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;
}
basic_block bb;
block_stmt_iterator last;
edge e;
+ edge_iterator ei;
tree stmt, label;
FOR_EACH_BB (bb)
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 (e = bb->succ; e; e = e->succ_next)
+ 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)
{
/* Remove the RETURN_EXPR if we may fall though to the exit
instead. */
- gcc_assert (bb->succ);
- gcc_assert (!bb->succ->succ_next);
- gcc_assert (bb->succ->dest == EXIT_BLOCK_PTR);
+ gcc_assert (EDGE_COUNT (bb->succs) == 1);
+ gcc_assert (EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR);
if (bb->next_bb == EXIT_BLOCK_PTR
&& !TREE_OPERAND (stmt, 0))
{
bsi_remove (&last);
- bb->succ->flags |= EDGE_FALLTHRU;
+ EDGE_SUCC (bb, 0)->flags |= EDGE_FALLTHRU;
}
continue;
}
continue;
/* Find a fallthru edge and emit the goto if necessary. */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_FALLTHRU)
break;
/* 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 (dest->pred->pred_next == NULL
+ if (EDGE_COUNT (dest->preds) == 1
&& ! phi_nodes (dest)
&& dest != EXIT_BLOCK_PTR)
{
Except for the entry block. */
src = e->src;
if ((e->flags & EDGE_ABNORMAL) == 0
- && src->succ->succ_next == NULL
+ && EDGE_COUNT (src->succs) == 1
&& src != ENTRY_BLOCK_PTR)
{
*bsi = bsi_last (src);
dest = split_edge (e);
if (new_bb)
*new_bb = dest;
- e = dest->pred;
+ e = EDGE_PRED (dest, 0);
goto restart;
}
/* 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;
-
- blocks = n_basic_blocks;
+ edge_iterator ei;
- bsi_commit_edge_inserts_1 (ENTRY_BLOCK_PTR->succ);
+ bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR, 0), NULL);
FOR_EACH_BB (bb)
- for (e = bb->succ; e; e = e->succ_next)
- bsi_commit_edge_inserts_1 (e);
-
- if (new_blocks)
- *new_blocks = n_basic_blocks - blocks;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ 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;
/* 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 (e = dest->pred; e; e = e->pred_next)
- 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;
}
/* Callback for walk_tree, check that all elements with address taken are
- properly noticed as such. */
+ properly noticed as such. The DATA is an int* that is 1 if TP was seen
+ inside a PHI node. */
static tree
verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
{
tree t = *tp, x;
+ bool in_phi = (data != NULL);
if (TYPE_P (t))
*walk_subtrees = 0;
We check for constants explicitly since they are not considered
gimple invariants if they overflowed. */
#define CHECK_OP(N, MSG) \
- do { if (TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, N))) != 'c' \
- && !is_gimple_val (TREE_OPERAND (t, N))) \
+ do { if (!CONSTANT_CLASS_P (TREE_OPERAND (t, N)) \
+ && !is_gimple_val (TREE_OPERAND (t, N))) \
{ error (MSG); return TREE_OPERAND (t, N); }} while (0)
switch (TREE_CODE (t))
break;
case ADDR_EXPR:
+ /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
+ dead PHIs that take the address of something. But if the PHI
+ result is dead, the fact that it takes the address of anything
+ is irrelevant. Because we can not tell from here if a PHI result
+ is dead, we just skip this check for PHIs altogether. This means
+ we may be missing "valid" checks, but what can you do?
+ This was PR19217. */
+ if (in_phi)
+ break;
+
/* Skip any references (they will be checked when we recurse down the
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");
t = TREE_OPERAND (t, 0);
}
- if (TREE_CODE_CLASS (TREE_CODE (t)) != 'c'
- && !is_gimple_lvalue (t))
+ if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
{
error ("Invalid reference prefix.");
return t;
{
if (!tree_could_throw_p (stmt))
{
- error ("Statement marked for throw, but doesn't.");
+ error ("Statement marked for throw, but doesn%'t.");
goto fail;
}
if (!last_in_block && tree_can_throw_internal (stmt))
static bool
tree_node_can_be_shared (tree t)
{
- if (TYPE_P (t) || DECL_P (t)
+ if (IS_TYPE_OR_DECL_P (t)
/* We check for constants explicitly since they are not considered
gimple invariants if they overflowed. */
- || TREE_CODE_CLASS (TREE_CODE (t)) == 'c'
+ || 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)
/* We check for constants explicitly since they are not considered
gimple invariants if they overflowed. */
- && (TREE_CODE_CLASS (TREE_CODE (TREE_OPERAND (t, 1))) == 'c'
+ && (CONSTANT_CLASS_P (TREE_OPERAND (t, 1))
|| is_gimple_min_invariant (TREE_OPERAND (t, 1))))
|| (TREE_CODE (t) == COMPONENT_REF
|| TREE_CODE (t) == REALPART_EXPR
err |= true;
}
- addr = walk_tree (&t, verify_expr, NULL, NULL);
+ addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
if (addr)
{
debug_generic_stmt (addr);
block_stmt_iterator bsi;
tree stmt;
edge e;
+ edge_iterator ei;
if (ENTRY_BLOCK_PTR->stmt_list)
{
err = 1;
}
- for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
if (e->flags & EDGE_FALLTHRU)
{
error ("Fallthru to exit from bb %d\n", e->src->index);
{
bool found_ctrl_stmt = false;
+ stmt = NULL_TREE;
+
/* Skip labels on the start of basic block. */
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
- if (TREE_CODE (bsi_stmt (bsi)) != LABEL_EXPR)
+ tree prev_stmt = stmt;
+
+ stmt = bsi_stmt (bsi);
+
+ if (TREE_CODE (stmt) != LABEL_EXPR)
break;
- if (label_to_block (LABEL_EXPR_LABEL (bsi_stmt (bsi))) != bb)
+ if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
+ {
+ error ("Nonlocal label %s is not first "
+ "in a sequence of labels in bb %d",
+ IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))),
+ bb->index);
+ err = 1;
+ }
+
+ if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
{
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)))
+ if (decl_function_context (LABEL_EXPR_LABEL (stmt))
!= current_function_decl)
{
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 (is_ctrl_stmt (stmt))
{
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_FALLTHRU)
{
error ("Fallthru edge after a control statement in bb %d \n",
|| !(false_edge->flags & EDGE_FALSE_VALUE)
|| (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
|| (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
- || bb->succ->succ_next->succ_next)
+ || EDGE_COUNT (bb->succs) >= 3)
{
error ("Wrong outgoing edge flags at end of bb %d\n",
bb->index);
if (!has_label_p (true_edge->dest,
GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
{
- error ("`then' label does not match edge at end of bb %d\n",
+ error ("%<then%> label does not match edge at end of bb %d\n",
bb->index);
err = 1;
}
if (!has_label_p (false_edge->dest,
GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
{
- error ("`else' label does not match edge at end of bb %d\n",
+ error ("%<else%> label does not match edge at end of bb %d\n",
bb->index);
err = 1;
}
{
/* FIXME. We should double check that the labels in the
destination blocks have their address taken. */
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE))
|| !(e->flags & EDGE_ABNORMAL))
break;
case RETURN_EXPR:
- if (!bb->succ || bb->succ->succ_next
- || (bb->succ->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
+ if (EDGE_COUNT (bb->succs) != 1
+ || (EDGE_SUCC (bb, 0)->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
| EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
{
error ("Wrong outgoing edge flags at end of bb %d\n", bb->index);
err = 1;
}
- if (bb->succ->dest != EXIT_BLOCK_PTR)
+ if (EDGE_SUCC (bb, 0)->dest != EXIT_BLOCK_PTR)
{
error ("Return edge does not point to exit in bb %d\n",
bb->index);
err = 1;
}
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (!e->dest->aux)
{
if (label_bb->aux != (void *)2)
{
- error ("Missing edge %i->%i\n",
+ error ("Missing edge %i->%i",
bb->index, label_bb->index);
err = 1;
}
}
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
e->dest->aux = (void *)0;
}
}
-/* Updates phi nodes after creating forwarder block joined
+/* Updates phi nodes after creating a forwarder block joined
by edge FALLTHRU. */
static void
tree_make_forwarder_block (edge fallthru)
{
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;
- if (!bb->pred->pred_next)
+ if (EDGE_COUNT (bb->preds) == 1)
return;
/* If we redirected a branch we must create new phi nodes at the
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 (e = bb->pred; e; e = e->pred_next)
+ 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)
+tree_forwarder_block_p (basic_block bb, bool phi_wanted)
{
block_stmt_iterator bsi;
- edge e;
-
- /* 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. */
- if (!bb->succ
- || bb->succ->succ_next
- || bb->succ->dest == EXIT_BLOCK_PTR
- || (bb->succ->flags & EDGE_ABNORMAL)
- || bb == ENTRY_BLOCK_PTR)
- {
- bb_ann (bb)->forwardable = 0;
- return false;
- }
- /* Successors of the entry block are not forwarders. */
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
- 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;
- }
+ /* BB must have a single outgoing edge. */
+ if (EDGE_COUNT (bb->succs) != 1
+ /* If PHI_WANTED is false, BB must not have any PHI nodes.
+ Otherwise, BB must have PHI nodes. */
+ || (phi_nodes (bb) != NULL_TREE) != phi_wanted
+ /* BB may not be a predecessor of EXIT_BLOCK_PTR. */
+ || EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR
+ /* 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. */
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ /* Now walk through the statements backward. We can ignore labels,
+ anything else means this is not a forwarder block. */
+ for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
tree stmt = bsi_stmt (bsi);
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. */
+
+static inline bool
+has_abnormal_incoming_edge_p (basic_block bb)
+{
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ return true;
+
+ return false;
+}
-/* Thread jumps over empty statements.
+/* 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. */
- This code should _not_ thread over obviously equivalent conditions
- as that requires nontrivial updates to the SSA graph. */
-
static bool
-thread_jumps (void)
+remove_forwarder_block (basic_block bb, basic_block **worklist)
{
- edge e, next, last, old;
- basic_block bb, dest, tmp, old_dest, dom;
+ edge succ = EDGE_SUCC (bb, 0), e, s;
+ basic_block dest = succ->dest;
+ tree label;
tree phi;
- int arg;
- bool retval = false;
+ edge_iterator ei;
+ block_stmt_iterator bsi, bsi_to;
+ bool seen_abnormal_edge = false;
+
+ /* 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;
- FOR_EACH_BB (bb)
- bb_ann (bb)->forwardable = 1;
+ /* If the destination block consists of a nonlocal label, do not merge
+ it. */
+ label = first_stmt (dest);
+ if (label
+ && TREE_CODE (label) == LABEL_EXPR
+ && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+ return false;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
+ /* 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))
{
- /* Don't waste time on unreachable blocks. */
- if (!bb->pred)
- continue;
+ seen_abnormal_edge = true;
- /* 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;
-
- /* Examine each of our block's successors to see if it is
- forwardable. */
- for (e = bb->succ; e; e = next)
+ if (has_abnormal_incoming_edge_p (dest)
+ || phi_nodes (dest) != NULL_TREE)
+ return false;
+ }
+
+ /* 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)
{
- int freq;
- gcov_type count;
- next = e->succ_next;
-
- /* 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))
+ s = find_edge (e->src, dest);
+ if (!s)
continue;
- count = e->count;
- freq = EDGE_FREQUENCY (e);
-
- /* Now walk through as many forwarder block as possible to
- find the ultimate destination we want to thread our jump
- to. */
- last = e->dest->succ;
- bb_ann (e->dest)->forwardable = 0;
- for (dest = e->dest->succ->dest;
- tree_forwarder_block_p (dest);
- last = dest->succ,
- dest = dest->succ->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 (dest->succ->dest == EXIT_BLOCK_PTR)
- break;
-
- bb_ann (dest)->forwardable = 0;
- dest->frequency -= freq;
- if (dest->frequency < 0)
- dest->frequency = 0;
- dest->count -= count;
- if (dest->count < 0)
- dest->count = 0;
- dest->succ->count -= count;
- if (dest->succ->count < 0)
- dest->succ->count = 0;
- }
+ if (!phi_alternatives_equal (dest, succ, s))
+ return false;
+ }
+ }
- /* Reset the forwardable marks to 1. */
- for (tmp = e->dest;
- tmp != dest;
- tmp = tmp->succ->dest)
- bb_ann (tmp)->forwardable = 1;
+ /* 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);
- if (dest == e->dest)
- 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)
- continue;
+ 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, false))
+ *(*worklist)++ = s->src;
+ }
+ }
- old = find_edge (bb, dest);
- }
- }
+ if (seen_abnormal_edge)
+ {
+ /* Move the labels to the new block, so that the redirection of
+ the abnormal edges works. */
- /* Perform the redirection. */
- retval = true;
- old_dest = e->dest;
- e = redirect_edge_and_branch (e, dest);
+ 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);
+ }
+ }
- if (!old)
+ /* Update the dominators. */
+ if (dom_info_available_p (CDI_DOMINATORS))
+ {
+ basic_block dom, dombb, domdest;
+
+ 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);
+
+ set_immediate_dominator (CDI_DOMINATORS, dest, dom);
+ }
+
+ /* And kill the forwarder block. */
+ delete_basic_block (bb);
+
+ return true;
+}
+
+/* Removes forwarder blocks. */
+
+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;
+
+ FOR_EACH_BB (bb)
+ {
+ if (tree_forwarder_block_p (bb, false))
+ *current++ = bb;
+ }
+
+ while (current != worklist)
+ {
+ bb = *--current;
+ changed |= remove_forwarder_block (bb, ¤t);
+ }
+
+ free (worklist);
+ return changed;
+}
+
+/* Merge the PHI nodes at BB into those at BB's sole successor. */
+
+static void
+remove_forwarder_block_with_phi (basic_block bb)
+{
+ edge succ = EDGE_SUCC (bb, 0);
+ basic_block dest = succ->dest;
+ tree label;
+ basic_block dombb, domdest, dom;
+
+ /* 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;
+
+ /* If the destination block consists of a nonlocal label, do not
+ merge it. */
+ label = first_stmt (dest);
+ if (label
+ && TREE_CODE (label) == LABEL_EXPR
+ && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+ return;
+
+ /* Redirect each incoming edge to BB to DEST. */
+ while (EDGE_COUNT (bb->preds) > 0)
+ {
+ edge e = EDGE_PRED (bb, 0), s;
+ tree phi;
+
+ s = find_edge (e->src, dest);
+ if (s)
+ {
+ /* We already have an edge S from E->src to DEST. If S and
+ E->dest's sole successor edge have the same PHI arguments
+ at DEST, redirect S to DEST. */
+ if (phi_alternatives_equal (dest, s, succ))
{
- /* 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);
- }
+ e = redirect_edge_and_branch (e, dest);
+ PENDING_STMT (e) = NULL_TREE;
+ continue;
}
- /* 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 = old_dest->succ->dest;
+ /* PHI arguments are different. Create a forwarder block by
+ splitting E so that we can merge PHI arguments on E to
+ DEST. */
+ e = EDGE_SUCC (split_edge (e), 0);
+ }
- if (old_dest->pred)
- break;
+ s = redirect_edge_and_branch (e, dest);
- 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);
+ /* redirect_edge_and_branch must not create a new edge. */
+ gcc_assert (s == e);
- /* Now proceed like if we forwarded just over one edge at a time.
- Algorithm for forwarding over edge A --> B then is
+ /* Add to the PHI nodes at DEST each PHI argument removed at the
+ destination of E. */
+ for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
+ {
+ tree def = PHI_ARG_DEF (phi, succ->dest_idx);
- if (idom (B) == A)
- idom (B) = idom (A);
- recount_idom (A); */
+ if (TREE_CODE (def) == SSA_NAME)
+ {
+ tree var;
- for (; old_dest != dest; old_dest = tmp)
+ /* If DEF is one of the results of PHI nodes removed during
+ redirection, replace it with the PHI argument that used
+ to be on E. */
+ for (var = PENDING_STMT (e); var; var = TREE_CHAIN (var))
{
- tmp = old_dest->succ->dest;
+ tree old_arg = TREE_PURPOSE (var);
+ tree new_arg = TREE_VALUE (var);
- if (get_immediate_dominator (CDI_DOMINATORS, tmp) == old_dest)
+ if (def == old_arg)
{
- dom = get_immediate_dominator (CDI_DOMINATORS, old_dest);
- set_immediate_dominator (CDI_DOMINATORS, tmp, dom);
+ def = new_arg;
+ break;
}
-
- dom = recount_dominator (CDI_DOMINATORS, old_dest);
- set_immediate_dominator (CDI_DOMINATORS, old_dest, dom);
}
}
+
+ add_phi_arg (phi, def, s);
}
- /* Reset the forwardable bit on our block since it's no longer in
- a forwarding chain path. */
- bb_ann (bb)->forwardable = 1;
+ PENDING_STMT (e) = NULL;
}
- return retval;
+ /* Update the dominators. */
+ 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);
+
+ set_immediate_dominator (CDI_DOMINATORS, dest, dom);
+
+ /* Remove BB since all of BB's incoming edges have been redirected
+ to DEST. */
+ delete_basic_block (bb);
+}
+
+/* This pass merges PHI nodes if one feeds into another. For example,
+ suppose we have the following:
+
+ goto <bb 9> (<L9>);
+
+<L8>:;
+ tem_17 = foo ();
+
+ # tem_6 = PHI <tem_17(8), tem_23(7)>;
+<L9>:;
+
+ # tem_3 = PHI <tem_6(9), tem_2(5)>;
+<L10>:;
+
+ Then we merge the first PHI node into the second one like so:
+
+ goto <bb 9> (<L10>);
+
+<L8>:;
+ tem_17 = foo ();
+
+ # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>;
+<L10>:;
+*/
+
+static void
+merge_phi_nodes (void)
+{
+ basic_block *worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+ basic_block *current = worklist;
+ basic_block bb;
+
+ calculate_dominance_info (CDI_DOMINATORS);
+
+ /* Find all PHI nodes that we may be able to merge. */
+ FOR_EACH_BB (bb)
+ {
+ basic_block dest;
+
+ /* Look for a forwarder block with PHI nodes. */
+ if (!tree_forwarder_block_p (bb, true))
+ continue;
+
+ dest = EDGE_SUCC (bb, 0)->dest;
+
+ /* We have to feed into another basic block with PHI
+ nodes. */
+ if (!phi_nodes (dest)
+ /* We don't want to deal with a basic block with
+ abnormal edges. */
+ || has_abnormal_incoming_edge_p (bb))
+ continue;
+
+ if (!dominated_by_p (CDI_DOMINATORS, dest, bb))
+ {
+ /* If BB does not dominate DEST, then the PHI nodes at
+ DEST must be the only users of the results of the PHI
+ nodes at BB. */
+ *current++ = bb;
+ }
+ }
+
+ /* Now let's drain WORKLIST. */
+ while (current != worklist)
+ {
+ bb = *--current;
+ remove_forwarder_block_with_phi (bb);
+ }
+
+ free (worklist);
+}
+
+static bool
+gate_merge_phi (void)
+{
+ return 1;
}
+struct tree_opt_pass pass_merge_phi = {
+ "mergephi", /* name */
+ gate_merge_phi, /* gate */
+ merge_phi_nodes, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_MERGE_PHI, /* tv_id */
+ PROP_cfg | PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */
+ | TODO_verify_ssa,
+ 0 /* letter */
+};
/* 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;
- /* Verify that all targets will be TARGET. */
- for (tmp = src->succ; tmp; tmp = tmp->succ_next)
- 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);
tree act;
basic_block new_bb;
edge e;
+ edge_iterator ei;
new_bb = create_empty_bb (bb);
/* Redirect the outgoing edges. */
- new_bb->succ = bb->succ;
- bb->succ = NULL;
- for (e = new_bb->succ; e; e = e->succ_next)
+ new_bb->succs = bb->succs;
+ bb->succs = NULL;
+ FOR_EACH_EDGE (e, ei, new_bb->succs)
e->src = new_bb;
if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
return true;
}
-
/* Create a duplicate of the basic block BB. NOTE: This does not
preserve SSA form. */
new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ /* 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 = PHI_CHAIN (phi))
{
mark_for_rewrite (PHI_RESULT (phi));
+ create_phi_node (PHI_RESULT (phi), 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))
return new_bb;
}
+/* Basic block BB_COPY was created by code duplication. Add phi node
+ arguments for edges going out of BB_COPY. The blocks that were
+ duplicated have rbi->duplicated set to one. */
+
+void
+add_phi_args_after_copy_bb (basic_block bb_copy)
+{
+ basic_block bb, dest;
+ edge e, e_copy;
+ edge_iterator ei;
+ tree phi, phi_copy, phi_next, def;
+
+ bb = bb_copy->rbi->original;
+
+ FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
+ {
+ if (!phi_nodes (e_copy->dest))
+ continue;
+
+ if (e_copy->dest->rbi->duplicated)
+ dest = e_copy->dest->rbi->original;
+ else
+ dest = e_copy->dest;
+
+ e = find_edge (bb, dest);
+ if (!e)
+ {
+ /* During loop unrolling the target of the latch edge is copied.
+ In this case we are not looking for edge to dest, but to
+ duplicated block whose original was dest. */
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (e->dest->rbi->duplicated
+ && e->dest->rbi->original == dest)
+ break;
+
+ gcc_assert (e != NULL);
+ }
+
+ for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
+ phi;
+ phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
+ {
+ 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);
+ }
+ }
+}
+
+/* Blocks in REGION_COPY array of length N_REGION were created by
+ duplication of basic blocks. Add phi node arguments for edges
+ going from these blocks. */
+
+void
+add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
+{
+ unsigned i;
+
+ for (i = 0; i < n_region; i++)
+ region_copy[i]->rbi->duplicated = 1;
+
+ for (i = 0; i < n_region; i++)
+ add_phi_args_after_copy_bb (region_copy[i]);
+
+ for (i = 0; i < n_region; i++)
+ region_copy[i]->rbi->duplicated = 0;
+}
+
+/* Maps the old ssa name FROM_NAME to TO_NAME. */
+
+struct ssa_name_map_entry
+{
+ tree from_name;
+ tree to_name;
+};
+
+/* Hash function for ssa_name_map_entry. */
+
+static hashval_t
+ssa_name_map_entry_hash (const void *entry)
+{
+ const struct ssa_name_map_entry *en = entry;
+ return SSA_NAME_VERSION (en->from_name);
+}
+
+/* Equality function for ssa_name_map_entry. */
+
+static int
+ssa_name_map_entry_eq (const void *in_table, const void *ssa_name)
+{
+ const struct ssa_name_map_entry *en = in_table;
+
+ return en->from_name == ssa_name;
+}
+
+/* Allocate duplicates of ssa names in list DEFINITIONS and store the mapping
+ to MAP. */
+
+void
+allocate_ssa_names (bitmap definitions, htab_t *map)
+{
+ tree name;
+ struct ssa_name_map_entry *entry;
+ PTR *slot;
+ unsigned ver;
+ bitmap_iterator bi;
+
+ if (!*map)
+ *map = htab_create (10, ssa_name_map_entry_hash,
+ ssa_name_map_entry_eq, free);
+ EXECUTE_IF_SET_IN_BITMAP (definitions, 0, ver, bi)
+ {
+ name = ssa_name (ver);
+ slot = htab_find_slot_with_hash (*map, name, SSA_NAME_VERSION (name),
+ INSERT);
+ if (*slot)
+ entry = *slot;
+ else
+ {
+ entry = xmalloc (sizeof (struct ssa_name_map_entry));
+ entry->from_name = name;
+ *slot = entry;
+ }
+ entry->to_name = duplicate_ssa_name (name, SSA_NAME_DEF_STMT (name));
+ }
+}
+
+/* Rewrite the definition DEF in statement STMT to new ssa name as specified
+ by the mapping MAP. */
+
+static void
+rewrite_to_new_ssa_names_def (def_operand_p def, tree stmt, htab_t map)
+{
+ tree name = DEF_FROM_PTR (def);
+ struct ssa_name_map_entry *entry;
+
+ gcc_assert (TREE_CODE (name) == SSA_NAME);
+
+ entry = htab_find_with_hash (map, name, SSA_NAME_VERSION (name));
+ if (!entry)
+ return;
+
+ SET_DEF (def, entry->to_name);
+ SSA_NAME_DEF_STMT (entry->to_name) = stmt;
+}
+
+/* Rewrite the USE to new ssa name as specified by the mapping MAP. */
+
+static void
+rewrite_to_new_ssa_names_use (use_operand_p use, htab_t map)
+{
+ tree name = USE_FROM_PTR (use);
+ struct ssa_name_map_entry *entry;
+
+ if (TREE_CODE (name) != SSA_NAME)
+ return;
+
+ entry = htab_find_with_hash (map, name, SSA_NAME_VERSION (name));
+ if (!entry)
+ return;
+
+ SET_USE (use, entry->to_name);
+}
+
+/* Rewrite the ssa names in basic block BB to new ones as specified by the
+ mapping MAP. */
+
+void
+rewrite_to_new_ssa_names_bb (basic_block bb, htab_t map)
+{
+ unsigned i;
+ edge e;
+ edge_iterator ei;
+ tree phi, stmt;
+ block_stmt_iterator bsi;
+ use_optype uses;
+ vuse_optype vuses;
+ def_optype defs;
+ v_may_def_optype v_may_defs;
+ v_must_def_optype v_must_defs;
+ stmt_ann_t ann;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ break;
+
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ {
+ rewrite_to_new_ssa_names_def (PHI_RESULT_PTR (phi), phi, map);
+ if (e)
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)) = 1;
+ }
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ {
+ stmt = bsi_stmt (bsi);
+ get_stmt_operands (stmt);
+ ann = stmt_ann (stmt);
+
+ uses = USE_OPS (ann);
+ for (i = 0; i < NUM_USES (uses); i++)
+ rewrite_to_new_ssa_names_use (USE_OP_PTR (uses, i), map);
+
+ defs = DEF_OPS (ann);
+ for (i = 0; i < NUM_DEFS (defs); i++)
+ rewrite_to_new_ssa_names_def (DEF_OP_PTR (defs, i), stmt, map);
+
+ vuses = VUSE_OPS (ann);
+ for (i = 0; i < NUM_VUSES (vuses); i++)
+ rewrite_to_new_ssa_names_use (VUSE_OP_PTR (vuses, i), map);
+
+ v_may_defs = V_MAY_DEF_OPS (ann);
+ for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+ {
+ rewrite_to_new_ssa_names_use
+ (V_MAY_DEF_OP_PTR (v_may_defs, i), map);
+ rewrite_to_new_ssa_names_def
+ (V_MAY_DEF_RESULT_PTR (v_may_defs, i), stmt, map);
+ }
+
+ 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_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 = PHI_CHAIN (phi))
+ {
+ rewrite_to_new_ssa_names_use
+ (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e), map);
+
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ tree op = PHI_ARG_DEF_FROM_EDGE (phi, e);
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op) = 1;
+ }
+ }
+}
+
+/* Rewrite the ssa names in N_REGION blocks REGION to the new ones as specified
+ by the mapping MAP. */
+
+void
+rewrite_to_new_ssa_names (basic_block *region, unsigned n_region, htab_t map)
+{
+ unsigned r;
+
+ for (r = 0; r < n_region; r++)
+ rewrite_to_new_ssa_names_bb (region[r], map);
+}
+
+/* Duplicates a REGION (set of N_REGION basic blocks) with just a single
+ important exit edge EXIT. By important we mean that no SSA name defined
+ inside region is live over the other exit edges of the region. All entry
+ edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
+ to the duplicate of the region. SSA form, dominance and loop information
+ is updated. The new basic blocks are stored to REGION_COPY in the same
+ order as they had in REGION, provided that REGION_COPY is not NULL.
+ The function returns false if it is unable to copy the region,
+ true otherwise. */
+
+bool
+tree_duplicate_sese_region (edge entry, edge exit,
+ basic_block *region, unsigned n_region,
+ basic_block *region_copy)
+{
+ unsigned i, n_doms, ver;
+ bool free_region_copy = false, copying_header = false;
+ struct loop *loop = entry->dest->loop_father;
+ edge exit_copy;
+ bitmap definitions;
+ tree phi;
+ basic_block *doms;
+ htab_t ssa_name_map = NULL;
+ edge redirected;
+ bitmap_iterator bi;
+
+ if (!can_copy_bbs_p (region, n_region))
+ return false;
+
+ /* Some sanity checking. Note that we do not check for all possible
+ missuses of the functions. I.e. if you ask to copy something weird,
+ it will work, but the state of structures probably will not be
+ correct. */
+
+ for (i = 0; i < n_region; i++)
+ {
+ /* We do not handle subloops, i.e. all the blocks must belong to the
+ same loop. */
+ if (region[i]->loop_father != loop)
+ return false;
+
+ if (region[i] != entry->dest
+ && region[i] == loop->header)
+ return false;
+ }
+
+ loop->copy = loop;
+
+ /* In case the function is used for loop header copying (which is the primary
+ use), ensure that EXIT and its copy will be new latch and entry edges. */
+ if (loop->header == entry->dest)
+ {
+ copying_header = true;
+ loop->copy = loop->outer;
+
+ if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
+ return false;
+
+ for (i = 0; i < n_region; i++)
+ if (region[i] != exit->src
+ && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
+ return false;
+ }
+
+ if (!region_copy)
+ {
+ region_copy = xmalloc (sizeof (basic_block) * n_region);
+ free_region_copy = true;
+ }
+
+ gcc_assert (!any_marked_for_rewrite_p ());
+
+ /* Record blocks outside the region that are duplicated by something
+ inside. */
+ doms = xmalloc (sizeof (basic_block) * n_basic_blocks);
+ n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
+
+ copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop);
+ definitions = marked_ssa_names ();
+
+ if (copying_header)
+ {
+ loop->header = exit->dest;
+ loop->latch = exit->src;
+ }
+
+ /* Redirect the entry and add the phi node arguments. */
+ redirected = redirect_edge_and_branch (entry, entry->dest->rbi->copy);
+ gcc_assert (redirected != 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
+ was dominated by something inside needs recounting as well. */
+ set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
+ doms[n_doms++] = entry->dest->rbi->original;
+ iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
+ free (doms);
+
+ /* Add the other phi node arguments. */
+ add_phi_args_after_copy (region_copy, n_region);
+
+ /* Add phi nodes for definitions at exit. TODO -- once we have immediate
+ uses, it should be possible to emit phi nodes just for definitions that
+ are used outside region. */
+ EXECUTE_IF_SET_IN_BITMAP (definitions, 0, ver, bi)
+ {
+ 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);
+
+ SSA_NAME_DEF_STMT (name) = phi;
+ }
+
+ /* And create new definitions inside region and its copy. TODO -- once we
+ have immediate uses, it might be better to leave definitions in region
+ unchanged, create new ssa names for phi nodes on exit, and rewrite
+ the uses, to avoid changing the copied region. */
+ allocate_ssa_names (definitions, &ssa_name_map);
+ rewrite_to_new_ssa_names (region, n_region, ssa_name_map);
+ allocate_ssa_names (definitions, &ssa_name_map);
+ rewrite_to_new_ssa_names (region_copy, n_region, ssa_name_map);
+ htab_delete (ssa_name_map);
+
+ if (free_region_copy)
+ free (region_copy);
+
+ unmark_all_for_rewrite ();
+ BITMAP_XFREE (definitions);
+
+ return true;
+}
/* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
/* Pretty print of the loops intermediate representation. */
static void print_loop (FILE *, struct loop *, int);
-static void print_pred_bbs (FILE *, edge);
-static void print_succ_bbs (FILE *, edge);
+static void print_pred_bbs (FILE *, basic_block bb);
+static void print_succ_bbs (FILE *, basic_block bb);
/* Print the predecessors indexes of edge E on FILE. */
static void
-print_pred_bbs (FILE *file, edge e)
+print_pred_bbs (FILE *file, basic_block bb)
{
- if (e == NULL)
- return;
-
- else if (e->pred_next == NULL)
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
fprintf (file, "bb_%d", e->src->index);
-
- else
- {
- fprintf (file, "bb_%d, ", e->src->index);
- print_pred_bbs (file, e->pred_next);
- }
}
/* Print the successors indexes of edge E on FILE. */
static void
-print_succ_bbs (FILE *file, edge e)
+print_succ_bbs (FILE *file, basic_block bb)
{
- if (e == NULL)
- return;
- else if (e->succ_next == NULL)
- fprintf (file, "bb_%d", e->dest->index);
- else
- {
- fprintf (file, "bb_%d, ", e->dest->index);
- print_succ_bbs (file, e->succ_next);
- }
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ fprintf (file, "bb_%d", e->src->index);
}
{
/* Print the basic_block's header. */
fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
- print_pred_bbs (file, bb->pred);
+ print_pred_bbs (file, bb);
fprintf (file, "}, succs = {");
- print_succ_bbs (file, bb->succ);
+ print_succ_bbs (file, bb);
fprintf (file, "})\n");
/* Print the basic_block's body. */
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
{
edge e;
- for (e = bb->succ; e; e = e->succ_next)
- 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 ();
+ }
}
}
mark that edge as fake and remove it later. */
#ifdef ENABLE_CHECKING
if (stmt == last_stmt)
- for (e = bb->succ; e; e = e->succ_next)
- gcc_assert (e->dest != EXIT_BLOCK_PTR);
+ {
+ e = find_edge (bb, EXIT_BLOCK_PTR);
+ gcc_assert (e == NULL);
+ }
#endif
/* Note that the following may create a new basic block
tree_purge_dead_eh_edges (basic_block bb)
{
bool changed = false;
- edge e, next;
+ edge e;
+ edge_iterator ei;
tree stmt = last_stmt (bb);
if (stmt && tree_can_throw_internal (stmt))
return false;
- for (e = bb->succ; e ; e = next)
+ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
- next = e->succ_next;
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,
- { changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i)); });
+ EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
+ {
+ changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
+ }
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 */
};
{
basic_block bb;
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 (e = bb->succ; e ; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
{
split_edge (e);
}
}
+ end_recording_case_labels ();
}
struct tree_opt_pass pass_split_crit_edges =
#endif
tree last;
edge e;
+ edge_iterator ei;
if (warn_missing_noreturn
&& !TREE_THIS_VOLATILE (cfun->decl)
- && EXIT_BLOCK_PTR->pred == NULL
+ && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
&& !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
- warning ("%Jfunction might be possible candidate for attribute `noreturn'",
+ warning ("%Jfunction might be possible candidate for "
+ "attribute %<noreturn%>",
cfun->decl);
/* If we have a path to EXIT, then we do return. */
if (TREE_THIS_VOLATILE (cfun->decl)
- && EXIT_BLOCK_PTR->pred != NULL)
+ && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
{
#ifdef USE_MAPPED_LOCATION
location = UNKNOWN_LOCATION;
#else
locus = NULL;
#endif
- for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
{
last = last_stmt (e->src);
if (TREE_CODE (last) == RETURN_EXPR
#ifdef USE_MAPPED_LOCATION
if (location == UNKNOWN_LOCATION)
location = cfun->function_end_locus;
- warning ("%H`noreturn' function does return", &location);
+ warning ("%H%<noreturn%> function does return", &location);
#else
if (!locus)
locus = &cfun->function_end_locus;
- warning ("%H`noreturn' function does return", locus);
+ warning ("%H%<noreturn%> function does return", locus);
#endif
}
/* If we see "return;" in some basic block, then we do reach the end
without returning a value. */
else if (warn_return_type
- && EXIT_BLOCK_PTR->pred != NULL
+ && !TREE_NO_WARNING (cfun->decl)
+ && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
&& !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
{
- for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
{
tree last = last_stmt (e->src);
if (TREE_CODE (last) == RETURN_EXPR
locus = &cfun->function_end_locus;
warning ("%Hcontrol reaches end of non-void function", locus);
#endif
+ TREE_NO_WARNING (cfun->decl) = 1;
break;
}
}
edge *true_edge,
edge *false_edge)
{
- edge e = b->succ;
+ edge e = EDGE_SUCC (b, 0);
if (e->flags & EDGE_TRUE_VALUE)
{
*true_edge = e;
- *false_edge = e->succ_next;
+ *false_edge = EDGE_SUCC (b, 1);
}
else
{
*false_edge = e;
- *true_edge = e->succ_next;
+ *true_edge = EDGE_SUCC (b, 1);
}
}
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