/* 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 "cfgloop.h"
#include "cfglayout.h"
#include "hashtab.h"
+#include "tree-ssa-propagate.h"
/* This file contains functions for building the Control Flow Graph (CFG)
for a function tree. */
/* Initial capacity for the basic block array. */
static const int initial_cfg_capacity = 20;
-/* Mapping of labels to their associated blocks. This can greatly speed up
- 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
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,gc) *);
/* 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 tree_forwarder_block_p (basic_block);
+static bool tree_forwarder_block_p (basic_block, bool);
static void tree_cfg2vcg (FILE *);
/* Flowgraph optimization and cleanup. */
static void remove_bb (basic_block);
static bool cleanup_control_flow (void);
static bool cleanup_control_expr_graph (basic_block, block_stmt_iterator);
+static edge find_taken_edge_computed_goto (basic_block, tree);
static edge find_taken_edge_cond_expr (basic_block, tree);
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);
+void
+init_empty_tree_cfg (void)
+{
+ /* Initialize the basic block array. */
+ init_flow ();
+ profile_status = PROFILE_ABSENT;
+ n_basic_blocks = 0;
+ last_basic_block = 0;
+ VARRAY_BB_INIT (basic_block_info, initial_cfg_capacity, "basic_block_info");
+
+ /* Build a mapping of labels to their associated blocks. */
+ VARRAY_BB_INIT (label_to_block_map, initial_cfg_capacity,
+ "label to block map");
+
+ ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
+ EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
+
+ create_block_annotation (ENTRY_BLOCK_PTR);
+ create_block_annotation (EXIT_BLOCK_PTR);
+}
/*---------------------------------------------------------------------------
Create basic blocks
/* Register specific tree functions. */
tree_register_cfg_hooks ();
- /* Initialize rbi_pool. */
- alloc_rbi_pool ();
-
- /* Initialize the basic block array. */
- init_flow ();
- profile_status = PROFILE_ABSENT;
- n_basic_blocks = 0;
- last_basic_block = 0;
- VARRAY_BB_INIT (basic_block_info, initial_cfg_capacity, "basic_block_info");
memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
- /* Build a mapping of labels to their associated blocks. */
- VARRAY_BB_INIT (label_to_block_map, initial_cfg_capacity,
- "label to block map");
-
- ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
- EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
+ init_empty_tree_cfg ();
found_computed_goto = 0;
make_blocks (*tp);
if (n_basic_blocks == 0)
create_empty_bb (ENTRY_BLOCK_PTR);
- create_block_annotation (ENTRY_BLOCK_PTR);
- create_block_annotation (EXIT_BLOCK_PTR);
-
/* Adjust the size of the array. */
VARRAY_GROW (basic_block_info, n_basic_blocks);
}
}
+#ifdef ENABLE_CHECKING
+ verify_stmts ();
+#endif
+
/* Dump a textual representation of the flowgraph. */
if (dump_file)
dump_tree_cfg (dump_file, dump_flags);
Edge creation
---------------------------------------------------------------------------*/
+/* Fold COND_EXPR_COND of each COND_EXPR. */
+
+void
+fold_cond_expr_cond (void)
+{
+ basic_block bb;
+
+ FOR_EACH_BB (bb)
+ {
+ tree stmt = last_stmt (bb);
+
+ if (stmt
+ && TREE_CODE (stmt) == COND_EXPR)
+ {
+ tree cond = fold (COND_EXPR_COND (stmt));
+ if (integer_zerop (cond))
+ COND_EXPR_COND (stmt) = boolean_false_node;
+ else if (integer_onep (cond))
+ COND_EXPR_COND (stmt) = boolean_true_node;
+ }
+ }
+}
+
/* Join all the blocks in the flowgraph. */
static void
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);
builder inserted for completeness. */
remove_fake_exit_edges ();
+ /* Fold COND_EXPR_COND of each COND_EXPR. */
+ fold_cond_expr_cond ();
+
/* Clean up the graph and warn for unreachable code. */
cleanup_tree_cfg ();
}
gcc_assert (last);
switch (TREE_CODE (last))
{
+ case RESX_EXPR:
+ break;
case CALL_EXPR:
/* If this function receives a nonlocal goto, then we need to
make edges from this call site to all the nonlocal goto
/* Return the basic block holding label DEST. */
basic_block
-label_to_block (tree dest)
+label_to_block_fn (struct function *ifun, tree dest)
{
int uid = LABEL_DECL_UID (dest);
bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
uid = LABEL_DECL_UID (dest);
}
- return VARRAY_BB (label_to_block_map, uid);
+ if (VARRAY_SIZE (ifun->cfg->x_label_to_block_map) <= (unsigned int)uid)
+ return NULL;
+ return VARRAY_BB (ifun->cfg->x_label_to_block_map, uid);
}
-
/* Create edges for a goto statement at block BB. */
static void
make_goto_expr_edges (basic_block bb)
{
- tree goto_t, dest;
+ tree goto_t;
basic_block target_bb;
int for_call;
block_stmt_iterator last = bsi_last (bb);
CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
from a nonlocal goto. */
if (TREE_CODE (goto_t) != GOTO_EXPR)
- {
- dest = error_mark_node;
- for_call = 1;
- }
+ for_call = 1;
else
{
- dest = GOTO_DESTINATION (goto_t);
+ tree dest = GOTO_DESTINATION (goto_t);
for_call = 0;
/* A GOTO to a local label creates normal edges. */
}
+/* Cleanup cfg and repair loop structures. */
+
+void
+cleanup_tree_cfg_loop (void)
+{
+ bitmap changed_bbs = BITMAP_ALLOC (NULL);
+
+ cleanup_tree_cfg ();
+
+ fix_loop_structure (current_loops, changed_bbs);
+ calculate_dominance_info (CDI_DOMINATORS);
+
+ /* This usually does nothing. But sometimes parts of cfg that originally
+ were inside a loop get out of it due to edge removal (since they
+ become unreachable by back edges from latch). */
+ rewrite_into_loop_closed_ssa (changed_bbs, TODO_update_ssa);
+
+ BITMAP_FREE (changed_bbs);
+
+#ifdef ENABLE_CHECKING
+ verify_loop_structure (current_loops);
+#endif
+}
+
/* Cleanup useless labels in basic blocks. This is something we wish
to do early because it allows us to group case labels before creating
the edges for the CFG, and it speeds up block statement iterators in
i = 0;
while (i < old_size - 1)
{
- tree base_case, base_label, base_high, type;
+ tree base_case, base_label, base_high;
base_case = TREE_VEC_ELT (labels, i);
gcc_assert (base_case);
continue;
}
- type = TREE_TYPE (CASE_LOW (base_case));
base_high = CASE_HIGH (base_case) ?
CASE_HIGH (base_case) : CASE_LOW (base_case);
i++;
{
tree stmt;
block_stmt_iterator bsi;
+ tree phi;
+
+ if (!single_succ_p (a))
+ return false;
- if (EDGE_COUNT (a->succs) != 1)
+ if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
return false;
- if (EDGE_SUCC (a, 0)->flags & EDGE_ABNORMAL)
+ if (single_succ (a) != b)
return false;
- if (EDGE_SUCC (a, 0)->dest != b)
+ if (!single_pred_p (b))
return false;
if (b == EXIT_BLOCK_PTR)
return false;
- if (EDGE_COUNT (b->preds) > 1)
- return false;
-
/* If A ends by a statement causing exceptions or something similar, we
cannot merge the blocks. */
stmt = last_stmt (a);
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
return false;
- /* There may be no phi nodes at the start of b. Most of these degenerate
- phi nodes should be cleaned up by kill_redundant_phi_nodes. */
- if (phi_nodes (b))
- return false;
+ /* It must be possible to eliminate all phi nodes in B. If ssa form
+ is not up-to-date, we cannot eliminate any phis. */
+ phi = phi_nodes (b);
+ if (phi)
+ {
+ if (need_ssa_update_p ())
+ return false;
+
+ for (; phi; phi = PHI_CHAIN (phi))
+ if (!is_gimple_reg (PHI_RESULT (phi))
+ && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
+ return false;
+ }
/* Do not remove user labels. */
for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
return false;
}
+ /* Protect the loop latches. */
+ if (current_loops
+ && b->loop_father->latch == b)
+ return false;
+
return true;
}
+/* Replaces all uses of NAME by VAL. */
+
+void
+replace_uses_by (tree name, tree val)
+{
+ imm_use_iterator imm_iter;
+ use_operand_p use;
+ tree stmt;
+ edge e;
+ unsigned i;
+ VEC(tree,heap) *stmts = VEC_alloc (tree, heap, 20);
+
+ FOR_EACH_IMM_USE_SAFE (use, imm_iter, name)
+ {
+ stmt = USE_STMT (use);
+
+ SET_USE (use, val);
+
+ if (TREE_CODE (stmt) == PHI_NODE)
+ {
+ e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ /* This can only occur for virtual operands, since
+ for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
+ would prevent replacement. */
+ gcc_assert (!is_gimple_reg (name));
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
+ }
+ }
+ else
+ VEC_safe_push (tree, heap, stmts, stmt);
+ }
+
+ /* We do not update the statements in the loop above. Consider
+ x = w * w;
+
+ If we performed the update in the first loop, the statement
+ would be rescanned after first occurrence of w is replaced,
+ the new uses would be placed to the beginning of the list,
+ and we would never process them. */
+ for (i = 0; VEC_iterate (tree, stmts, i, stmt); i++)
+ {
+ tree rhs;
+
+ fold_stmt_inplace (stmt);
+
+ rhs = get_rhs (stmt);
+ if (TREE_CODE (rhs) == ADDR_EXPR)
+ recompute_tree_invarant_for_addr_expr (rhs);
+
+ update_stmt (stmt);
+ }
+
+ VEC_free (tree, heap, stmts);
+}
/* Merge block B into block A. */
{
block_stmt_iterator bsi;
tree_stmt_iterator last;
+ tree phi;
if (dump_file)
fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
+ /* Remove the phi nodes. */
+ bsi = bsi_last (a);
+ for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
+ {
+ tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
+ tree copy;
+
+ if (!may_propagate_copy (def, use)
+ /* Propagating pointers might cause the set of vops for statements
+ to be changed, and thus require ssa form update. */
+ || (is_gimple_reg (def)
+ && POINTER_TYPE_P (TREE_TYPE (def))))
+ {
+ gcc_assert (is_gimple_reg (def));
+
+ /* Note that just emitting the copies is fine -- there is no problem
+ with ordering of phi nodes. This is because A is the single
+ predecessor of B, therefore results of the phi nodes cannot
+ appear as arguments of the phi nodes. */
+ copy = build2 (MODIFY_EXPR, void_type_node, def, use);
+ bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
+ SET_PHI_RESULT (phi, NULL_TREE);
+ SSA_NAME_DEF_STMT (def) = copy;
+ }
+ else
+ replace_uses_by (def, use);
+ remove_phi_node (phi, NULL);
+ }
+
/* Ensure that B follows A. */
move_block_after (b, a);
- gcc_assert (EDGE_SUCC (a, 0)->flags & EDGE_FALLTHRU);
+ gcc_assert (single_succ_edge (a)->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. */
for (bsi = bsi_start (b); !bsi_end_p (bsi);)
{
if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
- bsi_remove (&bsi);
+ {
+ tree label = bsi_stmt (bsi);
+
+ bsi_remove (&bsi);
+ /* Now that we can thread computed gotos, we might have
+ a situation where we have a forced label in block B
+ However, the label at the start of block B might still be
+ used in other ways (think about the runtime checking for
+ Fortran assigned gotos). So we can not just delete the
+ label. Instead we move the label to the start of block A. */
+ if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
+ {
+ block_stmt_iterator dest_bsi = bsi_start (a);
+ bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
+ }
+ }
else
{
set_bb_for_stmt (bsi_stmt (bsi), a);
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 (0, "%Hwill never be executed", &loc);
+ return true;
+ }
}
switch (TREE_CODE (stmt))
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))
0 /* letter */
};
-
-/* Remove obviously useless statements in basic block BB. */
-
-static void
-cfg_remove_useless_stmts_bb (basic_block bb)
-{
- block_stmt_iterator bsi;
- tree stmt = NULL_TREE;
- tree cond, var = NULL_TREE, val = NULL_TREE;
- struct var_ann_d *ann;
-
- /* Check whether we come here from a condition, and if so, get the
- condition. */
- if (EDGE_COUNT (bb->preds) != 1
- || !(EDGE_PRED (bb, 0)->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
- return;
-
- 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 = (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)) == VAR_DECL
- || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL))
- {
- var = TREE_OPERAND (cond, 0);
- val = (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE
- ? boolean_true_node : boolean_false_node);
- }
- else
- {
- 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
- || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
- && (TREE_CODE (TREE_OPERAND (cond, 1)) == VAR_DECL
- || TREE_CODE (TREE_OPERAND (cond, 1)) == PARM_DECL
- || TREE_CONSTANT (TREE_OPERAND (cond, 1))))
- {
- var = TREE_OPERAND (cond, 0);
- val = TREE_OPERAND (cond, 1);
- }
- else
- return;
- }
-
- /* Only work for normal local variables. */
- ann = var_ann (var);
- if (!ann
- || ann->may_aliases
- || TREE_ADDRESSABLE (var))
- return;
-
- if (! TREE_CONSTANT (val))
- {
- ann = var_ann (val);
- if (!ann
- || ann->may_aliases
- || TREE_ADDRESSABLE (val))
- return;
- }
-
- /* Ignore floating point variables, since comparison behaves weird for
- them. */
- if (FLOAT_TYPE_P (TREE_TYPE (var)))
- return;
-
- for (bsi = bsi_start (bb); !bsi_end_p (bsi);)
- {
- stmt = bsi_stmt (bsi);
-
- /* If the THEN/ELSE clause merely assigns a value to a variable/parameter
- which is already known to contain that value, then remove the useless
- THEN/ELSE clause. */
- if (TREE_CODE (stmt) == MODIFY_EXPR
- && TREE_OPERAND (stmt, 0) == var
- && operand_equal_p (val, TREE_OPERAND (stmt, 1), 0))
- {
- bsi_remove (&bsi);
- continue;
- }
-
- /* Invalidate the var if we encounter something that could modify it.
- Likewise for the value it was previously set to. Note that we only
- consider values that are either a VAR_DECL or PARM_DECL so we
- can test for conflict very simply. */
- if (TREE_CODE (stmt) == ASM_EXPR
- || (TREE_CODE (stmt) == MODIFY_EXPR
- && (TREE_OPERAND (stmt, 0) == var
- || TREE_OPERAND (stmt, 0) == val)))
- return;
-
- bsi_next (&bsi);
- }
-}
-
-
-/* A CFG-aware version of remove_useless_stmts. */
-
-void
-cfg_remove_useless_stmts (void)
-{
- basic_block bb;
-
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
-#endif
-
- FOR_EACH_BB (bb)
- {
- cfg_remove_useless_stmts_bb (bb);
- }
-}
-
-
/* Remove PHI nodes associated with basic block BB and all edges out of BB. */
static void
while (phi)
{
tree next = PHI_CHAIN (phi);
- remove_phi_node (phi, NULL_TREE, bb);
+ remove_phi_node (phi, NULL_TREE);
phi = next;
}
remove_bb (basic_block bb)
{
block_stmt_iterator i;
+#ifdef USE_MAPPED_LOCATION
+ source_location loc = UNKNOWN_LOCATION;
+#else
source_locus loc = 0;
+#endif
if (dump_file)
{
}
}
+ /* If we remove the header or the latch of a loop, mark the loop for
+ removal by setting its header and latch to NULL. */
+ if (current_loops)
+ {
+ struct loop *loop = bb->loop_father;
+
+ if (loop->latch == bb
+ || loop->header == bb)
+ {
+ loop->latch = NULL;
+ loop->header = NULL;
+ }
+ }
+
/* Remove all the instructions in the block. */
for (i = bsi_start (bb); !bsi_end_p (i);)
{
{
release_defs (stmt);
- set_bb_for_stmt (stmt, NULL);
bsi_remove (&i);
}
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)
+ {
#ifdef USE_MAPPED_LOCATION
- loc = EXPR_LOCATION (stmt);
+ if (EXPR_HAS_LOCATION (stmt))
+ loc = EXPR_LOCATION (stmt);
#else
- loc = EXPR_LOCUS (stmt);
+ source_locus t;
+ t = EXPR_LOCUS (stmt);
+ if (t && LOCATION_LINE (*t) > 0)
+ loc = t;
#endif
+ }
}
/* If requested, give a warning that the first statement in the
block is unreachable. We walk statements backwards in the
loop above, so the last statement we process is the first statement
in the block. */
- if (warn_notreached && loc)
#ifdef USE_MAPPED_LOCATION
- warning ("%Hwill never be executed", &loc);
+ if (warn_notreached && loc > BUILTINS_LOCATION)
+ warning (0, "%Hwill never be executed", &loc);
#else
- warning ("%Hwill never be executed", loc);
+ if (warn_notreached && loc)
+ warning (0, "%Hwill never be executed", loc);
#endif
remove_phi_nodes_and_edges_for_unreachable_block (bb);
}
+/* A list of all the noreturn calls passed to modify_stmt.
+ cleanup_control_flow uses it to detect cases where a mid-block
+ indirect call has been turned into a noreturn call. When this
+ happens, all the instructions after the call are no longer
+ reachable and must be deleted as dead. */
+
+VEC(tree,gc) *modified_noreturn_calls;
+
/* Try to remove superfluous control structures. */
static bool
bool retval = false;
tree stmt;
+ /* Detect cases where a mid-block call is now known not to return. */
+ while (VEC_length (tree, modified_noreturn_calls))
+ {
+ stmt = VEC_pop (tree, modified_noreturn_calls);
+ bb = bb_for_stmt (stmt);
+ if (bb != NULL && last_stmt (bb) != stmt && noreturn_call_p (stmt))
+ split_block (bb, stmt);
+ }
+
FOR_EACH_BB (bb)
{
bsi = bsi_last (bb);
if (TREE_CODE (stmt) == COND_EXPR
|| TREE_CODE (stmt) == SWITCH_EXPR)
retval |= cleanup_control_expr_graph (bb, bsi);
+
+ /* If we had a computed goto which has a compile-time determinable
+ destination, then we can eliminate the goto. */
+ if (TREE_CODE (stmt) == GOTO_EXPR
+ && TREE_CODE (GOTO_DESTINATION (stmt)) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (GOTO_DESTINATION (stmt), 0)) == LABEL_DECL)
+ {
+ edge e;
+ tree label;
+ edge_iterator ei;
+ basic_block target_block;
+ bool removed_edge = false;
+
+ /* First look at all the outgoing edges. Delete any outgoing
+ edges which do not go to the right block. For the one
+ edge which goes to the right block, fix up its flags. */
+ label = TREE_OPERAND (GOTO_DESTINATION (stmt), 0);
+ target_block = label_to_block (label);
+ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
+ {
+ if (e->dest != target_block)
+ {
+ removed_edge = true;
+ remove_edge (e);
+ }
+ else
+ {
+ /* Turn off the EDGE_ABNORMAL flag. */
+ e->flags &= ~EDGE_ABNORMAL;
+
+ /* And set EDGE_FALLTHRU. */
+ e->flags |= EDGE_FALLTHRU;
+ ei_next (&ei);
+ }
+ }
+
+ /* If we removed one or more edges, then we will need to fix the
+ dominators. It may be possible to incrementally update them. */
+ if (removed_edge)
+ free_dominance_info (CDI_DOMINATORS);
+
+ /* Remove the GOTO_EXPR as it is not needed. The CFG has all the
+ relevant information we need. */
+ bsi_remove (&bsi);
+ retval = true;
+ }
+
+ /* Check for indirect calls that have been turned into
+ noreturn calls. */
+ if (noreturn_call_p (stmt) && remove_fallthru_edge (bb->succs))
+ {
+ free_dominance_info (CDI_DOMINATORS);
+ retval = true;
+ }
}
return retval;
}
bool retval = false;
tree expr = bsi_stmt (bsi), val;
- if (EDGE_COUNT (bb->succs) > 1)
+ if (!single_succ_p (bb))
{
edge e;
edge_iterator ei;
taken_edge->probability = REG_BR_PROB_BASE;
}
else
- taken_edge = EDGE_SUCC (bb, 0);
+ taken_edge = single_succ_edge (bb);
bsi_remove (&bsi);
taken_edge->flags = EDGE_FALLTHRU;
return retval;
}
+/* Remove any fallthru edge from EV. Return true if an edge was removed. */
+
+static bool
+remove_fallthru_edge (VEC(edge,gc) *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 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.
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 (COMPARISON_CLASS_P (val))
- val = fold (val);
-
- /* If VAL is not a constant, we can't determine which edge might
- be taken. */
- if (!really_constant_p (val))
+ if (! is_gimple_min_invariant (val))
return NULL;
if (TREE_CODE (stmt) == COND_EXPR)
if (TREE_CODE (stmt) == SWITCH_EXPR)
return find_taken_edge_switch_expr (bb, val);
+ if (computed_goto_p (stmt))
+ return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
+
gcc_unreachable ();
}
+/* Given a constant value VAL and the entry block BB to a GOTO_EXPR
+ statement, determine which of the outgoing edges will be taken out of the
+ block. Return NULL if either edge may be taken. */
+
+static edge
+find_taken_edge_computed_goto (basic_block bb, tree val)
+{
+ basic_block dest;
+ edge e = NULL;
+
+ dest = label_to_block (val);
+ if (dest)
+ {
+ e = find_edge (bb, dest);
+ gcc_assert (e != NULL);
+ }
+
+ return e;
+}
/* Given a constant value VAL and the entry block BB to a COND_EXPR
statement, determine which of the two edges will be taken out of the
edge true_edge, false_edge;
extract_true_false_edges_from_block (bb, &true_edge, &false_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
- may happen when comparing addresses (e.g., if (&var1 == 4)). */
- if (integer_nonzerop (val))
- return true_edge;
- else if (integer_zerop (val))
- return false_edge;
- else
- return NULL;
+
+ gcc_assert (TREE_CODE (val) == INTEGER_CST);
+ return (zero_p (val) ? false_edge : true_edge);
}
-
-/* Given a constant value VAL and the entry block BB to a SWITCH_EXPR
+/* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
statement, determine which edge will be taken out of the block. Return
NULL if any edge may be taken. */
basic_block dest_bb;
edge e;
- if (TREE_CODE (val) != INTEGER_CST)
- return NULL;
-
switch_expr = last_stmt (bb);
taken_case = find_case_label_for_value (switch_expr, val);
dest_bb = label_to_block (CASE_LABEL (taken_case));
{
static long max_num_merged_labels = 0;
unsigned long size, total = 0;
- int n_edges;
+ long num_edges;
basic_block bb;
const char * const fmt_str = "%-30s%-13s%12s\n";
const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
SCALE (size), LABEL (size));
- n_edges = 0;
+ num_edges = 0;
FOR_EACH_BB (bb)
- n_edges += EDGE_COUNT (bb->succs);
- size = n_edges * sizeof (struct edge_def);
+ num_edges += EDGE_COUNT (bb->succs);
+ size = num_edges * sizeof (struct edge_def);
total += size;
- fprintf (file, fmt_str_1, "Edges", n_edges, SCALE (size), LABEL (size));
+ fprintf (file, fmt_str_1, "Edges", num_edges, SCALE (size), LABEL (size));
size = n_basic_blocks * sizeof (struct bb_ann_d);
total += size;
static inline bool
stmt_starts_bb_p (tree t, tree prev_t)
{
- enum tree_code code;
-
if (t == NULL_TREE)
return false;
statement wasn't a label of the same type. This prevents the
creation of consecutive blocks that have nothing but a single
label. */
- code = TREE_CODE (t);
- if (code == LABEL_EXPR)
+ if (TREE_CODE (t) == LABEL_EXPR)
{
/* Nonlocal and computed GOTO targets always start a new block. */
- if (code == LABEL_EXPR
- && (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
- || FORCED_LABEL (LABEL_EXPR_LABEL (t))))
+ if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
+ || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
return true;
- if (prev_t && TREE_CODE (prev_t) == code)
+ if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
{
if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
return true;
{
/* Remove the RETURN_EXPR if we may fall though to the exit
instead. */
- gcc_assert (EDGE_COUNT (bb->succs) == 1);
- gcc_assert (EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR);
+ gcc_assert (single_succ_p (bb));
+ gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
if (bb->next_bb == EXIT_BLOCK_PTR
&& !TREE_OPERAND (stmt, 0))
{
bsi_remove (&last);
- EDGE_SUCC (bb, 0)->flags |= EDGE_FALLTHRU;
+ single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
}
continue;
}
free_blocks_annotations ();
label_to_block_map = NULL;
- free_rbi_pool ();
FOR_EACH_BB (bb)
bb->rbi = NULL;
}
gcc_unreachable ();
}
-/* Insert statement (or statement list) T before the statement
- pointed-to by iterator I. M specifies how to update iterator I
- after insertion (see enum bsi_iterator_update). */
+/* Mark statement T as modified, and update it. */
+static inline void
+update_modified_stmts (tree t)
+{
+ if (TREE_CODE (t) == STATEMENT_LIST)
+ {
+ tree_stmt_iterator i;
+ tree stmt;
+ for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
+ {
+ stmt = tsi_stmt (i);
+ update_stmt_if_modified (stmt);
+ }
+ }
+ else
+ update_stmt_if_modified (t);
+}
+
+/* Insert statement (or statement list) T before the statement
+ pointed-to by iterator I. M specifies how to update iterator I
+ after insertion (see enum bsi_iterator_update). */
void
bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
{
set_bb_for_stmt (t, i->bb);
+ update_modified_stmts (t);
tsi_link_before (&i->tsi, t, m);
- modify_stmt (t);
}
bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
{
set_bb_for_stmt (t, i->bb);
+ update_modified_stmts (t);
tsi_link_after (&i->tsi, t, m);
- modify_stmt (t);
}
{
tree t = bsi_stmt (*i);
set_bb_for_stmt (t, NULL);
+ delink_stmt_imm_use (t);
tsi_delink (&i->tsi);
+ mark_stmt_modified (t);
}
add_stmt_to_eh_region (stmt, eh_region);
}
+ delink_stmt_imm_use (orig_stmt);
*bsi_stmt_ptr (*bsi) = stmt;
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
+ update_modified_stmts (stmt);
}
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
hardly seems worth the effort. */
- if (EDGE_COUNT (dest->preds) == 1
+ if (single_pred_p (dest)
&& ! phi_nodes (dest)
&& dest != EXIT_BLOCK_PTR)
{
Except for the entry block. */
src = e->src;
if ((e->flags & EDGE_ABNORMAL) == 0
- && EDGE_COUNT (src->succs) == 1
+ && single_succ_p (src)
&& src != ENTRY_BLOCK_PTR)
{
*bsi = bsi_last (src);
dest = split_edge (e);
if (new_bb)
*new_bb = dest;
- e = EDGE_PRED (dest, 0);
+ e = single_pred_edge (dest);
goto restart;
}
edge e;
edge_iterator ei;
- bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR, 0), NULL);
+ bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
FOR_EACH_BB (bb)
FOR_EACH_EDGE (e, ei, bb->succs)
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)
/* 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;
}
break;
+ case ASSERT_EXPR:
+ x = fold (ASSERT_EXPR_COND (t));
+ if (x == boolean_false_node)
+ {
+ error ("ASSERT_EXPR with an always-false condition");
+ return *tp;
+ }
+ break;
+
case MODIFY_EXPR:
x = TREE_OPERAND (t, 0);
if (TREE_CODE (x) == BIT_FIELD_REF
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. */
{
int phi_num_args = PHI_NUM_ARGS (phi);
+ if (bb_for_stmt (phi) != bb)
+ {
+ error ("bb_for_stmt (phi) is set to a wrong basic block\n");
+ err |= true;
+ }
+
for (i = 0; i < phi_num_args; i++)
{
tree t = PHI_ARG_DEF (phi, i);
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);
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree stmt = bsi_stmt (bsi);
+
+ if (bb_for_stmt (stmt) != bb)
+ {
+ error ("bb_for_stmt (stmt) is set to a wrong basic block\n");
+ err |= true;
+ }
+
bsi_next (&bsi);
err |= verify_stmt (stmt, bsi_end_p (bsi));
addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
{
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)
{
- tree stmt = bsi_stmt (bsi);
error ("Label %s to block does not match in bb %d\n",
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)
{
- tree stmt = bsi_stmt (bsi);
error ("Label %s has incorrect context in bb %d\n",
IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))),
bb->index);
if (TREE_CODE (stmt) == LABEL_EXPR)
{
error ("Label %s in the middle of basic block %d\n",
- IDENTIFIER_POINTER (DECL_NAME (stmt)),
+ IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt))),
bb->index);
err = 1;
}
stmt = bsi_stmt (bsi);
+ err |= verify_eh_edges (stmt);
+
if (is_ctrl_stmt (stmt))
{
FOR_EACH_EDGE (e, ei, bb->succs)
break;
case RETURN_EXPR:
- if (EDGE_COUNT (bb->succs) != 1
- || (EDGE_SUCC (bb, 0)->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
- | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
+ if (!single_succ_p (bb)
+ || (single_succ_edge (bb)->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 (EDGE_SUCC (bb, 0)->dest != EXIT_BLOCK_PTR)
+ if (single_succ (bb) != EXIT_BLOCK_PTR)
{
error ("Return edge does not point to exit in bb %d\n",
bb->index);
dummy = fallthru->src;
bb = fallthru->dest;
- if (EDGE_COUNT (bb->preds) == 1)
+ if (single_pred_p (bb))
return;
/* If we redirected a branch we must create new phi nodes at the
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;
/* 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)
+ if (single_succ_p (bb) != 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
+ || single_succ (bb) == EXIT_BLOCK_PTR
/* Nor should this be an infinite loop. */
- || EDGE_SUCC (bb, 0)->dest == bb
+ || single_succ (bb) == bb
/* BB may not have an abnormal outgoing edge. */
- || (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL))
+ || (single_succ_edge (bb)->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_prev (&bsi))
{
tree stmt = bsi_stmt (bsi);
if (find_edge (ENTRY_BLOCK_PTR, bb))
return false;
+ if (current_loops)
+ {
+ basic_block dest;
+ /* Protect loop latches, headers and preheaders. */
+ if (bb->loop_father->header == bb)
+ return false;
+ dest = EDGE_SUCC (bb, 0)->dest;
+
+ if (dest->loop_father->header == dest)
+ return false;
+ }
+
return true;
}
return false;
}
-/* Removes forwarder block BB. Returns false if this failed. If new
+/* 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. */
static bool
remove_forwarder_block (basic_block bb, basic_block **worklist)
{
- edge succ = EDGE_SUCC (bb, 0), e, s;
+ edge succ = single_succ_edge (bb), e, s;
basic_block dest = succ->dest;
tree label;
tree phi;
if (dest == bb)
return false;
- /* If the destination block consists of an nonlocal label, do not merge
+ /* If the destination block consists of a nonlocal label, do not merge
it. */
- label = first_stmt (bb);
+ label = first_stmt (dest);
if (label
&& TREE_CODE (label) == LABEL_EXPR
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
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))
+ if (tree_forwarder_block_p (s->src, false))
*(*worklist)++ = s->src;
}
}
FOR_EACH_BB (bb)
{
- if (tree_forwarder_block_p (bb))
+ if (tree_forwarder_block_p (bb, false))
*current++ = bb;
}
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 = single_succ_edge (bb);
+ 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))
+ {
+ e = redirect_edge_and_branch (e, dest);
+ PENDING_STMT (e) = NULL_TREE;
+ continue;
+ }
+
+ /* PHI arguments are different. Create a forwarder block by
+ splitting E so that we can merge PHI arguments on E to
+ DEST. */
+ e = single_succ_edge (split_edge (e));
+ }
+
+ s = redirect_edge_and_branch (e, dest);
+
+ /* redirect_edge_and_branch must not create a new edge. */
+ gcc_assert (s == e);
+
+ /* 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 (TREE_CODE (def) == SSA_NAME)
+ {
+ tree var;
+
+ /* 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))
+ {
+ tree old_arg = TREE_PURPOSE (var);
+ tree new_arg = TREE_VALUE (var);
+
+ if (def == old_arg)
+ {
+ def = new_arg;
+ break;
+ }
+ }
+ }
+
+ add_phi_arg (phi, def, s);
+ }
+
+ PENDING_STMT (e) = NULL;
+ }
+
+ /* 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 = single_succ (bb);
+
+ /* 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. */
return true;
}
+
/* Create a duplicate of the basic block BB. NOTE: This does not
preserve SSA form. */
{
basic_block new_bb;
block_stmt_iterator bsi, bsi_tgt;
- tree phi, val;
- ssa_op_iter op_iter;
+ tree phi;
new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
- /* 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. */
+ /* Copy the PHI nodes. We ignore PHI node arguments here because
+ the incoming edges have not been setup yet. */
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
- mark_for_rewrite (PHI_RESULT (phi));
- create_phi_node (PHI_RESULT (phi), new_bb);
+ tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
+ create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
}
+
+ /* Keep the chain of PHI nodes in the same order so that they can be
+ updated by ssa_redirect_edge. */
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))
{
- tree stmt = bsi_stmt (bsi);
- tree copy;
+ def_operand_p def_p;
+ ssa_op_iter op_iter;
+ tree stmt, copy;
+ int region;
+ stmt = bsi_stmt (bsi);
if (TREE_CODE (stmt) == LABEL_EXPR)
continue;
- /* Record the definitions. */
- get_stmt_operands (stmt);
-
- FOR_EACH_SSA_TREE_OPERAND (val, stmt, op_iter, SSA_OP_ALL_DEFS)
- mark_for_rewrite (val);
-
+ /* Create a new copy of STMT and duplicate STMT's virtual
+ operands. */
copy = unshare_expr (stmt);
-
- /* Copy also the virtual operands. */
- get_stmt_ann (copy);
- copy_virtual_operands (copy, stmt);
-
bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
+ copy_virtual_operands (copy, stmt);
+ region = lookup_stmt_eh_region (stmt);
+ if (region >= 0)
+ add_stmt_to_eh_region (copy, region);
+
+ /* Create new names for all the definitions created by COPY and
+ add replacement mappings for each new name. */
+ FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
+ create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
}
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. */
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);
}
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
basic_block *region, unsigned n_region,
basic_block *region_copy)
{
- unsigned i, n_doms, ver;
+ unsigned i, n_doms;
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;
+ int total_freq, entry_freq;
if (!can_copy_bbs_p (region, n_region))
return false;
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
free_region_copy = true;
}
- gcc_assert (!any_marked_for_rewrite_p ());
+ gcc_assert (!need_ssa_update_p ());
- /* Record blocks outside the region that are duplicated by something
+ /* Record blocks outside the region that are dominated by something
inside. */
doms = xmalloc (sizeof (basic_block) * n_basic_blocks);
n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
+ total_freq = entry->dest->frequency;
+ entry_freq = EDGE_FREQUENCY (entry);
+ /* Fix up corner cases, to avoid division by zero or creation of negative
+ frequencies. */
+ if (total_freq == 0)
+ total_freq = 1;
+ else if (entry_freq > total_freq)
+ entry_freq = total_freq;
+
copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop);
- definitions = marked_ssa_names ();
+ scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
+ total_freq);
+ scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
if (copying_header)
{
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. */
+ 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 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);
+ /* Update the SSA web. */
+ update_ssa (TODO_update_ssa);
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) */
void
}
fprintf (file, ")\n");
+ if (flags & TDF_DETAILS)
+ dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
if (flags & TDF_RAW)
{
dump_node (fn, TDF_SLIM | flags, file);
/* When GIMPLE is lowered, the variables are no longer available in
BIND_EXPRs, so display them separately. */
- if (cfun && cfun->unexpanded_var_list)
+ if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
{
ignore_topmost_bind = true;
}
}
- if (basic_block_info)
+ if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
{
/* Make a CFG based dump. */
check_bb_profile (ENTRY_BLOCK_PTR, file);
static bool
tree_block_ends_with_condjump_p (basic_block bb)
{
- tree stmt = tsi_stmt (bsi_last (bb).tsi);
- return (TREE_CODE (stmt) == COND_EXPR);
+ tree stmt = last_stmt (bb);
+ return (stmt && TREE_CODE (stmt) == COND_EXPR);
}
tree call;
/* NORETURN and LONGJMP calls already have an edge to exit.
- CONST, PURE and ALWAYS_RETURN calls do not need one.
+ CONST and PURE calls do not need one.
We don't currently check for CONST and PURE here, although
it would be a good idea, because those attributes are
figured out from the RTL in mark_constant_function, and
leads to different results from -fbranch-probabilities. */
call = get_call_expr_in (t);
if (call
- && !(call_expr_flags (call) & (ECF_NORETURN | ECF_ALWAYS_RETURN)))
+ && !(call_expr_flags (call) & ECF_NORETURN))
return true;
if (TREE_CODE (t) == ASM_EXPR
remove_phi_args (e);
}
+/*---------------------------------------------------------------------------
+ Helper functions for Loop versioning
+ ---------------------------------------------------------------------------*/
+
+/* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
+ of 'first'. Both of them are dominated by 'new_head' basic block. When
+ 'new_head' was created by 'second's incoming edge it received phi arguments
+ on the edge by split_edge(). Later, additional edge 'e' was created to
+ connect 'new_head' and 'first'. Now this routine adds phi args on this
+ additional edge 'e' that new_head to second edge received as part of edge
+ splitting.
+*/
+
+static void
+tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
+ basic_block new_head, edge e)
+{
+ tree phi1, phi2;
+ edge e2 = find_edge (new_head, second);
+
+ /* Because NEW_HEAD has been created by splitting SECOND's incoming
+ edge, we should always have an edge from NEW_HEAD to SECOND. */
+ gcc_assert (e2 != NULL);
+
+ /* Browse all 'second' basic block phi nodes and add phi args to
+ edge 'e' for 'first' head. PHI args are always in correct order. */
+
+ for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
+ phi2 && phi1;
+ phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
+ {
+ tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
+ add_phi_arg (phi1, def, e);
+ }
+}
+
+/* Adds a if else statement to COND_BB with condition COND_EXPR.
+ SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
+ the destination of the ELSE part. */
+static void
+tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
+ basic_block cond_bb, void *cond_e)
+{
+ block_stmt_iterator bsi;
+ tree goto1 = NULL_TREE;
+ tree goto2 = NULL_TREE;
+ tree new_cond_expr = NULL_TREE;
+ tree cond_expr = (tree) cond_e;
+ edge e0;
+
+ /* Build new conditional expr */
+ goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
+ goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
+ new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
+
+ /* Add new cond in cond_bb. */
+ bsi = bsi_start (cond_bb);
+ bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
+ /* Adjust edges appropriately to connect new head with first head
+ as well as second head. */
+ e0 = single_succ_edge (cond_bb);
+ e0->flags &= ~EDGE_FALLTHRU;
+ e0->flags |= EDGE_FALSE_VALUE;
+}
+
struct cfg_hooks tree_cfg_hooks = {
"tree",
tree_verify_flow_info,
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 */
+ tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
+ tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
+ tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
+ extract_true_false_edges_from_block, /* extract_cond_bb_edges */
+ flush_pending_stmts /* flush_pending_stmts */
};
edge e;
edge_iterator ei;
- if (warn_missing_noreturn
- && !TREE_THIS_VOLATILE (cfun->decl)
- && 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%>",
- cfun->decl);
-
/* If we have a path to EXIT, then we do return. */
if (TREE_THIS_VOLATILE (cfun->decl)
&& EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
#ifdef USE_MAPPED_LOCATION
if (location == UNKNOWN_LOCATION)
location = cfun->function_end_locus;
- warning ("%H%<noreturn%> function does return", &location);
+ warning (0, "%H%<noreturn%> function does return", &location);
#else
if (!locus)
locus = &cfun->function_end_locus;
- warning ("%H%<noreturn%> function does return", locus);
+ warning (0, "%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
+ && !TREE_NO_WARNING (cfun->decl)
&& EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
&& !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
{
location = EXPR_LOCATION (last);
if (location == UNKNOWN_LOCATION)
location = cfun->function_end_locus;
- warning ("%Hcontrol reaches end of non-void function", &location);
+ warning (0, "%Hcontrol reaches end of non-void function", &location);
#else
locus = EXPR_LOCUS (last);
if (!locus)
locus = &cfun->function_end_locus;
- warning ("%Hcontrol reaches end of non-void function", locus);
+ warning (0, "%Hcontrol reaches end of non-void function", locus);
#endif
+ TREE_NO_WARNING (cfun->decl) = 1;
break;
}
}
0 /* letter */
};
-#include "gt-tree-cfg.h"
+/* Emit noreturn warnings. */
+
+static void
+execute_warn_function_noreturn (void)
+{
+ if (warn_missing_noreturn
+ && !TREE_THIS_VOLATILE (cfun->decl)
+ && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
+ && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
+ warning (0, "%Jfunction might be possible candidate for "
+ "attribute %<noreturn%>",
+ cfun->decl);
+}
+
+struct tree_opt_pass pass_warn_function_noreturn =
+{
+ NULL, /* name */
+ NULL, /* gate */
+ execute_warn_function_noreturn, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ 0, /* tv_id */
+ PROP_cfg, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+ 0 /* letter */
+};
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