/* SSA Dominator optimizations for trees
- Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
+ Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "tm_p.h"
#include "ggc.h"
#include "basic-block.h"
+#include "cfgloop.h"
#include "output.h"
-#include "errors.h"
#include "expr.h"
#include "function.h"
#include "diagnostic.h"
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
#include "langhooks.h"
+#include "params.h"
/* This file implements optimizations on the dominator tree. */
and its maximum index rather than use a varray. */
tree *cond_equivalences;
unsigned int max_cond_equivalences;
-
- /* If we can thread this edge this field records the new target. */
- edge redirection_target;
};
(null). When we finish processing the block, we pop off entries and
remove the expressions from the global hash table until we hit the
marker. */
-static VEC(tree_on_heap) *avail_exprs_stack;
-
-/* Stack of trees used to restore the global currdefs to its original
- state after completing optimization of a block and its dominator children.
-
- An SSA_NAME indicates that the current definition of the underlying
- variable should be set to the given SSA_NAME.
-
- A _DECL node indicates that the underlying variable has no current
- definition.
-
- A NULL node is used to mark the last node associated with the
- current block. */
-static VEC(tree_on_heap) *block_defs_stack;
+static VEC(tree,heap) *avail_exprs_stack;
/* Stack of statements we need to rescan during finalization for newly
exposed variables.
expressions are removed from AVAIL_EXPRS. Else we may change the
hash code for an expression and be unable to find/remove it from
AVAIL_EXPRS. */
-static VEC(tree_on_heap) *stmts_to_rescan;
+static VEC(tree,heap) *stmts_to_rescan;
/* Structure for entries in the expression hash table.
/* The expression (rhs) we want to record. */
tree rhs;
- /* The annotation if this element corresponds to a statement. */
- stmt_ann_t ann;
+ /* The stmt pointer if this element corresponds to a statement. */
+ tree stmt;
/* The hash value for RHS/ann. */
hashval_t hash;
A NULL entry is used to mark the end of pairs which need to be
restored during finalization of this block. */
-static VEC(tree_on_heap) *const_and_copies_stack;
+static VEC(tree,heap) *const_and_copies_stack;
/* Bitmap of SSA_NAMEs known to have a nonzero value, even if we do not
know their exact value. */
A NULL entry is used to mark the end of names needing their
entry in NONZERO_VARS cleared during finalization of this block. */
-static VEC(tree_on_heap) *nonzero_vars_stack;
+static VEC(tree,heap) *nonzero_vars_stack;
/* Track whether or not we have changed the control flow graph. */
static bool cfg_altered;
long num_stmts;
long num_exprs_considered;
long num_re;
+ long num_const_prop;
+ long num_copy_prop;
};
static struct opt_stats_d opt_stats;
-/* Value range propagation record. Each time we encounter a conditional
- of the form SSA_NAME COND CONST we create a new vrp_element to record
- how the condition affects the possible values SSA_NAME may have.
-
- Each record contains the condition tested (COND), and the range of
- values the variable may legitimately have if COND is true. Note the
- range of values may be a smaller range than COND specifies if we have
- recorded other ranges for this variable. Each record also contains the
- block in which the range was recorded for invalidation purposes.
-
- Note that the current known range is computed lazily. This allows us
- to avoid the overhead of computing ranges which are never queried.
-
- When we encounter a conditional, we look for records which constrain
- the SSA_NAME used in the condition. In some cases those records allow
- us to determine the condition's result at compile time. In other cases
- they may allow us to simplify the condition.
-
- We also use value ranges to do things like transform signed div/mod
- operations into unsigned div/mod or to simplify ABS_EXPRs.
-
- Simple experiments have shown these optimizations to not be all that
- useful on switch statements (much to my surprise). So switch statement
- optimizations are not performed.
-
- Note carefully we do not propagate information through each statement
- in the block. i.e., if we know variable X has a value defined of
- [0, 25] and we encounter Y = X + 1, we do not track a value range
- for Y (which would be [1, 26] if we cared). Similarly we do not
- constrain values as we encounter narrowing typecasts, etc. */
-
-struct vrp_element
-{
- /* The highest and lowest values the variable in COND may contain when
- COND is true. Note this may not necessarily be the same values
- tested by COND if the same variable was used in earlier conditionals.
-
- Note this is computed lazily and thus can be NULL indicating that
- the values have not been computed yet. */
- tree low;
- tree high;
-
- /* The actual conditional we recorded. This is needed since we compute
- ranges lazily. */
- tree cond;
-
- /* The basic block where this record was created. We use this to determine
- when to remove records. */
- basic_block bb;
-};
-
-/* A hash table holding value range records (VRP_ELEMENTs) for a given
- SSA_NAME. We used to use a varray indexed by SSA_NAME_VERSION, but
- that gets awful wasteful, particularly since the density objects
- with useful information is very low. */
-static htab_t vrp_data;
-
-/* An entry in the VRP_DATA hash table. We record the variable and a
- varray of VRP_ELEMENT records associated with that variable. */
-struct vrp_hash_elt
-{
- tree var;
- varray_type records;
-};
-
-/* Array of variables which have their values constrained by operations
- in this basic block. We use this during finalization to know
- which variables need their VRP data updated. */
-
-/* Stack of SSA_NAMEs which had their values constrained by operations
- in this basic block. During finalization of this block we use this
- list to determine which variables need their VRP data updated.
-
- A NULL entry marks the end of the SSA_NAMEs associated with this block. */
-static VEC(tree_on_heap) *vrp_variables_stack;
-
struct eq_expr_value
{
tree src;
basic_block bb,
block_stmt_iterator);
static tree lookup_avail_expr (tree, bool);
-static hashval_t vrp_hash (const void *);
-static int vrp_eq (const void *, const void *);
static hashval_t avail_expr_hash (const void *);
static hashval_t real_avail_expr_hash (const void *);
static int avail_expr_eq (const void *, const void *);
static void record_cond (tree, tree);
static void record_const_or_copy (tree, tree);
static void record_equality (tree, tree);
-static tree update_rhs_and_lookup_avail_expr (tree, tree, bool);
-static tree simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *,
- tree, int);
-static tree simplify_cond_and_lookup_avail_expr (tree, stmt_ann_t, int);
-static tree simplify_switch_and_lookup_avail_expr (tree, int);
-static tree find_equivalent_equality_comparison (tree);
-static void record_range (tree, basic_block);
-static bool extract_range_from_cond (tree, tree *, tree *, int *);
static void record_equivalences_from_phis (basic_block);
static void record_equivalences_from_incoming_edge (basic_block);
-static bool eliminate_redundant_computations (struct dom_walk_data *,
- tree, stmt_ann_t);
+static bool eliminate_redundant_computations (tree);
static void record_equivalences_from_stmt (tree, int, stmt_ann_t);
-static void thread_across_edge (struct dom_walk_data *, edge);
+static void dom_thread_across_edge (struct dom_walk_data *, edge);
static void dom_opt_finalize_block (struct dom_walk_data *, basic_block);
static void dom_opt_initialize_block (struct dom_walk_data *, basic_block);
static void propagate_to_outgoing_edges (struct dom_walk_data *, basic_block);
static void remove_local_expressions_from_table (void);
static void restore_vars_to_original_value (void);
-static void restore_currdefs_to_original_value (void);
-static void register_definitions_for_stmt (tree);
static edge single_incoming_edge_ignoring_loop_edges (basic_block);
static void restore_nonzero_vars_to_original_value (void);
static inline bool unsafe_associative_fp_binop (tree);
-/* Local version of fold that doesn't introduce cruft. */
-
-static tree
-local_fold (tree t)
-{
- t = fold (t);
-
- /* Strip away useless type conversions. Both the NON_LVALUE_EXPR that
- may have been added by fold, and "useless" type conversions that might
- now be apparent due to propagation. */
- STRIP_USELESS_TYPE_CONVERSION (t);
-
- return t;
-}
/* Allocate an EDGE_INFO for edge E and attach it to E.
Return the new EDGE_INFO structure. */
{
struct edge_info *edge_info;
- edge_info = xcalloc (1, sizeof (struct edge_info));
+ edge_info = XCNEW (struct edge_info);
e->aux = edge_info;
return edge_info;
{
FOR_EACH_EDGE (e, ei, bb->preds)
{
- struct edge_info *edge_info = e->aux;
+ struct edge_info *edge_info = (struct edge_info *) e->aux;
if (edge_info)
{
- e->aux = edge_info->redirection_target;
if (edge_info->cond_equivalences)
free (edge_info->cond_equivalences);
free (edge_info);
+ e->aux = NULL;
}
}
}
{
struct dom_walk_data walk_data;
unsigned int i;
+ struct loops loops_info;
memset (&opt_stats, 0, sizeof (opt_stats));
- for (i = 0; i < num_referenced_vars; i++)
- var_ann (referenced_var (i))->current_def = NULL;
-
/* Create our hash tables. */
avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free);
- vrp_data = htab_create (ceil_log2 (num_ssa_names), vrp_hash, vrp_eq, free);
- avail_exprs_stack = VEC_alloc (tree_on_heap, 20);
- block_defs_stack = VEC_alloc (tree_on_heap, 20);
- const_and_copies_stack = VEC_alloc (tree_on_heap, 20);
- nonzero_vars_stack = VEC_alloc (tree_on_heap, 20);
- vrp_variables_stack = VEC_alloc (tree_on_heap, 20);
- stmts_to_rescan = VEC_alloc (tree_on_heap, 20);
+ avail_exprs_stack = VEC_alloc (tree, heap, 20);
+ const_and_copies_stack = VEC_alloc (tree, heap, 20);
+ nonzero_vars_stack = VEC_alloc (tree, heap, 20);
+ stmts_to_rescan = VEC_alloc (tree, heap, 20);
nonzero_vars = BITMAP_ALLOC (NULL);
need_eh_cleanup = BITMAP_ALLOC (NULL);
structure. */
walk_data.global_data = NULL;
walk_data.block_local_data_size = 0;
+ walk_data.interesting_blocks = NULL;
/* Now initialize the dominator walker. */
init_walk_dominator_tree (&walk_data);
calculate_dominance_info (CDI_DOMINATORS);
- /* If we prove certain blocks are unreachable, then we want to
- repeat the dominator optimization process as PHI nodes may
- have turned into copies which allows better propagation of
- values. So we repeat until we do not identify any new unreachable
- blocks. */
- do
- {
- /* Optimize the dominator tree. */
- cfg_altered = false;
-
- /* Recursively walk the dominator tree optimizing statements. */
- walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
-
- /* If we exposed any new variables, go ahead and put them into
- SSA form now, before we handle jump threading. This simplifies
- interactions between rewriting of _DECL nodes into SSA form
- and rewriting SSA_NAME nodes into SSA form after block
- duplication and CFG manipulation. */
- if (!bitmap_empty_p (vars_to_rename))
- {
- rewrite_into_ssa (false);
- bitmap_clear (vars_to_rename);
- }
+ /* We need to know which edges exit loops so that we can
+ aggressively thread through loop headers to an exit
+ edge. */
+ flow_loops_find (&loops_info);
+ mark_loop_exit_edges (&loops_info);
+ flow_loops_free (&loops_info);
- free_all_edge_infos ();
+ /* Clean up the CFG so that any forwarder blocks created by loop
+ canonicalization are removed. */
+ cleanup_tree_cfg ();
+ calculate_dominance_info (CDI_DOMINATORS);
- /* Thread jumps, creating duplicate blocks as needed. */
- cfg_altered |= thread_through_all_blocks ();
+ /* We need accurate information regarding back edges in the CFG
+ for jump threading. */
+ mark_dfs_back_edges ();
- /* Removal of statements may make some EH edges dead. Purge
- such edges from the CFG as needed. */
- if (!bitmap_empty_p (need_eh_cleanup))
- {
- cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
- bitmap_zero (need_eh_cleanup);
- }
+ /* Recursively walk the dominator tree optimizing statements. */
+ walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
- if (cfg_altered)
- free_dominance_info (CDI_DOMINATORS);
- cfg_altered |= cleanup_tree_cfg ();
- calculate_dominance_info (CDI_DOMINATORS);
+ {
+ block_stmt_iterator bsi;
+ basic_block bb;
+ FOR_EACH_BB (bb)
+ {
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ update_stmt_if_modified (bsi_stmt (bsi));
+ }
+ }
- rewrite_ssa_into_ssa ();
+ /* If we exposed any new variables, go ahead and put them into
+ SSA form now, before we handle jump threading. This simplifies
+ interactions between rewriting of _DECL nodes into SSA form
+ and rewriting SSA_NAME nodes into SSA form after block
+ duplication and CFG manipulation. */
+ update_ssa (TODO_update_ssa);
- /* Reinitialize the various tables. */
- bitmap_clear (nonzero_vars);
- htab_empty (avail_exprs);
- htab_empty (vrp_data);
+ free_all_edge_infos ();
- for (i = 0; i < num_referenced_vars; i++)
- var_ann (referenced_var (i))->current_def = NULL;
+ /* Thread jumps, creating duplicate blocks as needed. */
+ cfg_altered |= thread_through_all_blocks ();
- /* Finally, remove everything except invariants in SSA_NAME_VALUE.
+ /* Removal of statements may make some EH edges dead. Purge
+ such edges from the CFG as needed. */
+ if (!bitmap_empty_p (need_eh_cleanup))
+ {
+ cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup);
+ bitmap_zero (need_eh_cleanup);
+ }
- This must be done before we iterate as we might have a
- reference to an SSA_NAME which was removed by the call to
- rewrite_ssa_into_ssa.
+ if (cfg_altered)
+ free_dominance_info (CDI_DOMINATORS);
- Long term we will be able to let everything in SSA_NAME_VALUE
- persist. However, for now, we know this is the safe thing to do. */
- for (i = 0; i < num_ssa_names; i++)
- {
- tree name = ssa_name (i);
- tree value;
+ /* Finally, remove everything except invariants in SSA_NAME_VALUE.
- if (!name)
- continue;
+ Long term we will be able to let everything in SSA_NAME_VALUE
+ persist. However, for now, we know this is the safe thing to do. */
+ for (i = 0; i < num_ssa_names; i++)
+ {
+ tree name = ssa_name (i);
+ tree value;
- value = SSA_NAME_VALUE (name);
- if (value && !is_gimple_min_invariant (value))
- SSA_NAME_VALUE (name) = NULL;
- }
+ if (!name)
+ continue;
+
+ value = SSA_NAME_VALUE (name);
+ if (value && !is_gimple_min_invariant (value))
+ SSA_NAME_VALUE (name) = NULL;
}
- while (optimize > 1 && cfg_altered);
/* Debugging dumps. */
if (dump_file && (dump_flags & TDF_STATS))
dump_dominator_optimization_stats (dump_file);
- /* We emptied the hash table earlier, now delete it completely. */
+ /* Delete our main hashtable. */
htab_delete (avail_exprs);
- htab_delete (vrp_data);
-
- /* It is not necessary to clear CURRDEFS, REDIRECTION_EDGES, VRP_DATA,
- CONST_AND_COPIES, and NONZERO_VARS as they all get cleared at the bottom
- of the do-while loop above. */
/* And finalize the dominator walker. */
fini_walk_dominator_tree (&walk_data);
BITMAP_FREE (nonzero_vars);
BITMAP_FREE (need_eh_cleanup);
- VEC_free (tree_on_heap, block_defs_stack);
- VEC_free (tree_on_heap, avail_exprs_stack);
- VEC_free (tree_on_heap, const_and_copies_stack);
- VEC_free (tree_on_heap, nonzero_vars_stack);
- VEC_free (tree_on_heap, vrp_variables_stack);
- VEC_free (tree_on_heap, stmts_to_rescan);
+ VEC_free (tree, heap, avail_exprs_stack);
+ VEC_free (tree, heap, const_and_copies_stack);
+ VEC_free (tree, heap, nonzero_vars_stack);
+ VEC_free (tree, heap, stmts_to_rescan);
}
static bool
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_rename_vars
+ TODO_dump_func
+ | TODO_update_ssa
+ | TODO_cleanup_cfg
| TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};
-/* We are exiting BB, see if the target block begins with a conditional
- jump which has a known value when reached via BB. */
+/* Given a stmt CONDSTMT containing a COND_EXPR, canonicalize the
+ COND_EXPR into a canonical form. */
static void
-thread_across_edge (struct dom_walk_data *walk_data, edge e)
+canonicalize_comparison (tree condstmt)
{
- block_stmt_iterator bsi;
- tree stmt = NULL;
- tree phi;
-
- /* Each PHI creates a temporary equivalence, record them. */
- for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
- {
- tree src = PHI_ARG_DEF_FROM_EDGE (phi, e);
- tree dst = PHI_RESULT (phi);
-
- /* If the desired argument is not the same as this PHI's result
- and it is set by a PHI in this block, then we can not thread
- through this block. */
- if (src != dst
- && TREE_CODE (src) == SSA_NAME
- && TREE_CODE (SSA_NAME_DEF_STMT (src)) == PHI_NODE
- && bb_for_stmt (SSA_NAME_DEF_STMT (src)) == e->dest)
- return;
-
- record_const_or_copy (dst, src);
- register_new_def (dst, &block_defs_stack);
- }
-
- for (bsi = bsi_start (e->dest); ! bsi_end_p (bsi); bsi_next (&bsi))
- {
- tree lhs, cached_lhs;
-
- stmt = bsi_stmt (bsi);
-
- /* Ignore empty statements and labels. */
- if (IS_EMPTY_STMT (stmt) || TREE_CODE (stmt) == LABEL_EXPR)
- continue;
-
- /* If this is not a MODIFY_EXPR which sets an SSA_NAME to a new
- value, then stop our search here. Ideally when we stop a
- search we stop on a COND_EXPR or SWITCH_EXPR. */
- if (TREE_CODE (stmt) != MODIFY_EXPR
- || TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME)
- break;
-
- /* At this point we have a statement which assigns an RHS to an
- SSA_VAR on the LHS. We want to prove that the RHS is already
- available and that its value is held in the current definition
- of the LHS -- meaning that this assignment is a NOP when
- reached via edge E. */
- if (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME)
- cached_lhs = TREE_OPERAND (stmt, 1);
- else
- cached_lhs = lookup_avail_expr (stmt, false);
-
- lhs = TREE_OPERAND (stmt, 0);
-
- /* This can happen if we thread around to the start of a loop. */
- if (lhs == cached_lhs)
- break;
-
- /* If we did not find RHS in the hash table, then try again after
- temporarily const/copy propagating the operands. */
- if (!cached_lhs)
- {
- /* Copy the operands. */
- stmt_ann_t ann = stmt_ann (stmt);
- use_optype uses = USE_OPS (ann);
- vuse_optype vuses = VUSE_OPS (ann);
- tree *uses_copy = xmalloc (NUM_USES (uses) * sizeof (tree));
- tree *vuses_copy = xmalloc (NUM_VUSES (vuses) * sizeof (tree));
- unsigned int i;
-
- /* Make a copy of the uses into USES_COPY, then cprop into
- the use operands. */
- for (i = 0; i < NUM_USES (uses); i++)
- {
- tree tmp = NULL;
-
- uses_copy[i] = USE_OP (uses, i);
- if (TREE_CODE (USE_OP (uses, i)) == SSA_NAME)
- tmp = SSA_NAME_VALUE (USE_OP (uses, i));
- if (tmp && TREE_CODE (tmp) != VALUE_HANDLE)
- SET_USE_OP (uses, i, tmp);
- }
-
- /* Similarly for virtual uses. */
- for (i = 0; i < NUM_VUSES (vuses); i++)
- {
- tree tmp = NULL;
-
- vuses_copy[i] = VUSE_OP (vuses, i);
- if (TREE_CODE (VUSE_OP (vuses, i)) == SSA_NAME)
- tmp = SSA_NAME_VALUE (VUSE_OP (vuses, i));
- if (tmp && TREE_CODE (tmp) != VALUE_HANDLE)
- SET_VUSE_OP (vuses, i, tmp);
- }
-
- /* Try to lookup the new expression. */
- cached_lhs = lookup_avail_expr (stmt, false);
-
- /* Restore the statement's original uses/defs. */
- for (i = 0; i < NUM_USES (uses); i++)
- SET_USE_OP (uses, i, uses_copy[i]);
-
- for (i = 0; i < NUM_VUSES (vuses); i++)
- SET_VUSE_OP (vuses, i, vuses_copy[i]);
-
- free (uses_copy);
- free (vuses_copy);
-
- /* If we still did not find the expression in the hash table,
- then we can not ignore this statement. */
- if (! cached_lhs)
- break;
- }
-
- /* If the expression in the hash table was not assigned to an
- SSA_NAME, then we can not ignore this statement. */
- if (TREE_CODE (cached_lhs) != SSA_NAME)
- break;
-
- /* If we have different underlying variables, then we can not
- ignore this statement. */
- if (SSA_NAME_VAR (cached_lhs) != SSA_NAME_VAR (lhs))
- break;
+ tree cond = COND_EXPR_COND (condstmt);
+ tree op0;
+ tree op1;
+ enum tree_code code = TREE_CODE (cond);
- /* If CACHED_LHS does not represent the current value of the underlying
- variable in CACHED_LHS/LHS, then we can not ignore this statement. */
- if (var_ann (SSA_NAME_VAR (lhs))->current_def != cached_lhs)
- break;
+ if (!COMPARISON_CLASS_P (cond))
+ return;
- /* If we got here, then we can ignore this statement and continue
- walking through the statements in the block looking for a threadable
- COND_EXPR.
+ op0 = TREE_OPERAND (cond, 0);
+ op1 = TREE_OPERAND (cond, 1);
- We want to record an equivalence lhs = cache_lhs so that if
- the result of this statement is used later we can copy propagate
- suitably. */
- record_const_or_copy (lhs, cached_lhs);
- register_new_def (lhs, &block_defs_stack);
- }
+ /* If it would be profitable to swap the operands, then do so to
+ canonicalize the statement, enabling better optimization.
- /* If we stopped at a COND_EXPR or SWITCH_EXPR, then see if we know which
- arm will be taken. */
- if (stmt
- && (TREE_CODE (stmt) == COND_EXPR
- || TREE_CODE (stmt) == SWITCH_EXPR))
+ By placing canonicalization of such expressions here we
+ transparently keep statements in canonical form, even
+ when the statement is modified. */
+ if (tree_swap_operands_p (op0, op1, false))
{
- tree cond, cached_lhs;
-
- /* Now temporarily cprop the operands and try to find the resulting
- expression in the hash tables. */
- if (TREE_CODE (stmt) == COND_EXPR)
- cond = COND_EXPR_COND (stmt);
- else
- cond = SWITCH_COND (stmt);
-
- if (COMPARISON_CLASS_P (cond))
+ /* For relationals we need to swap the operands
+ and change the code. */
+ if (code == LT_EXPR
+ || code == GT_EXPR
+ || code == LE_EXPR
+ || code == GE_EXPR)
{
- tree dummy_cond, op0, op1;
- enum tree_code cond_code;
-
- op0 = TREE_OPERAND (cond, 0);
- op1 = TREE_OPERAND (cond, 1);
- cond_code = TREE_CODE (cond);
-
- /* Get the current value of both operands. */
- if (TREE_CODE (op0) == SSA_NAME)
- {
- tree tmp = SSA_NAME_VALUE (op0);
- if (tmp && TREE_CODE (tmp) != VALUE_HANDLE)
- op0 = tmp;
- }
-
- if (TREE_CODE (op1) == SSA_NAME)
- {
- tree tmp = SSA_NAME_VALUE (op1);
- if (tmp && TREE_CODE (tmp) != VALUE_HANDLE)
- op1 = tmp;
- }
-
- /* Stuff the operator and operands into our dummy conditional
- expression, creating the dummy conditional if necessary. */
- dummy_cond = walk_data->global_data;
- if (! dummy_cond)
- {
- dummy_cond = build (cond_code, boolean_type_node, op0, op1);
- dummy_cond = build (COND_EXPR, void_type_node,
- dummy_cond, NULL, NULL);
- walk_data->global_data = dummy_cond;
- }
- else
- {
- TREE_SET_CODE (COND_EXPR_COND (dummy_cond), cond_code);
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op0;
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1) = op1;
- }
-
- /* If the conditional folds to an invariant, then we are done,
- otherwise look it up in the hash tables. */
- cached_lhs = local_fold (COND_EXPR_COND (dummy_cond));
- if (! is_gimple_min_invariant (cached_lhs))
- {
- cached_lhs = lookup_avail_expr (dummy_cond, false);
- if (!cached_lhs || ! is_gimple_min_invariant (cached_lhs))
- cached_lhs = simplify_cond_and_lookup_avail_expr (dummy_cond,
- NULL,
- false);
- }
- }
- /* We can have conditionals which just test the state of a
- variable rather than use a relational operator. These are
- simpler to handle. */
- else if (TREE_CODE (cond) == SSA_NAME)
- {
- cached_lhs = cond;
- cached_lhs = SSA_NAME_VALUE (cached_lhs);
- if (cached_lhs && ! is_gimple_min_invariant (cached_lhs))
- cached_lhs = 0;
- }
- else
- cached_lhs = lookup_avail_expr (stmt, false);
-
- if (cached_lhs)
- {
- edge taken_edge = find_taken_edge (e->dest, cached_lhs);
- basic_block dest = (taken_edge ? taken_edge->dest : NULL);
-
- if (dest == e->dest)
- return;
-
- /* If we have a known destination for the conditional, then
- we can perform this optimization, which saves at least one
- conditional jump each time it applies since we get to
- bypass the conditional at our original destination. */
- if (dest)
- {
- struct edge_info *edge_info;
-
- update_bb_profile_for_threading (e->dest, EDGE_FREQUENCY (e),
- e->count, taken_edge);
- if (e->aux)
- edge_info = e->aux;
- else
- edge_info = allocate_edge_info (e);
- edge_info->redirection_target = taken_edge;
- bb_ann (e->dest)->incoming_edge_threaded = true;
- }
+ TREE_SET_CODE (cond, swap_tree_comparison (code));
+ swap_tree_operands (condstmt,
+ &TREE_OPERAND (cond, 0),
+ &TREE_OPERAND (cond, 1));
+ /* If one operand was in the operand cache, but the other is
+ not, because it is a constant, this is a case that the
+ internal updating code of swap_tree_operands can't handle
+ properly. */
+ if (TREE_CODE_CLASS (TREE_CODE (op0))
+ != TREE_CODE_CLASS (TREE_CODE (op1)))
+ update_stmt (condstmt);
}
}
}
-
/* Initialize local stacks for this optimizer and record equivalences
upon entry to BB. Equivalences can come from the edge traversed to
reach BB or they may come from PHI nodes at the start of BB. */
/* Push a marker on the stacks of local information so that we know how
far to unwind when we finalize this block. */
- VEC_safe_push (tree_on_heap, avail_exprs_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, block_defs_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, const_and_copies_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, nonzero_vars_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, vrp_variables_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, nonzero_vars_stack, NULL_TREE);
record_equivalences_from_incoming_edge (bb);
}
/* Given an expression EXPR (a relational expression or a statement),
- initialize the hash table element pointed by by ELEMENT. */
+ initialize the hash table element pointed to by ELEMENT. */
static void
initialize_hash_element (tree expr, tree lhs, struct expr_hash_elt *element)
we want to record the expression the statement evaluates. */
if (COMPARISON_CLASS_P (expr) || TREE_CODE (expr) == TRUTH_NOT_EXPR)
{
- element->ann = NULL;
+ element->stmt = NULL;
element->rhs = expr;
}
else if (TREE_CODE (expr) == COND_EXPR)
{
- element->ann = stmt_ann (expr);
+ element->stmt = expr;
element->rhs = COND_EXPR_COND (expr);
}
else if (TREE_CODE (expr) == SWITCH_EXPR)
{
- element->ann = stmt_ann (expr);
+ element->stmt = expr;
element->rhs = SWITCH_COND (expr);
}
else if (TREE_CODE (expr) == RETURN_EXPR && TREE_OPERAND (expr, 0))
{
- element->ann = stmt_ann (expr);
+ element->stmt = expr;
element->rhs = TREE_OPERAND (TREE_OPERAND (expr, 0), 1);
}
+ else if (TREE_CODE (expr) == GOTO_EXPR)
+ {
+ element->stmt = expr;
+ element->rhs = GOTO_DESTINATION (expr);
+ }
else
{
- element->ann = stmt_ann (expr);
+ element->stmt = expr;
element->rhs = TREE_OPERAND (expr, 1);
}
remove_local_expressions_from_table (void)
{
/* Remove all the expressions made available in this block. */
- while (VEC_length (tree_on_heap, avail_exprs_stack) > 0)
+ while (VEC_length (tree, avail_exprs_stack) > 0)
{
struct expr_hash_elt element;
- tree expr = VEC_pop (tree_on_heap, avail_exprs_stack);
+ tree expr = VEC_pop (tree, avail_exprs_stack);
if (expr == NULL_TREE)
break;
static void
restore_nonzero_vars_to_original_value (void)
{
- while (VEC_length (tree_on_heap, nonzero_vars_stack) > 0)
+ while (VEC_length (tree, nonzero_vars_stack) > 0)
{
- tree name = VEC_pop (tree_on_heap, nonzero_vars_stack);
+ tree name = VEC_pop (tree, nonzero_vars_stack);
if (name == NULL)
break;
static void
restore_vars_to_original_value (void)
{
- while (VEC_length (tree_on_heap, const_and_copies_stack) > 0)
+ while (VEC_length (tree, const_and_copies_stack) > 0)
{
tree prev_value, dest;
- dest = VEC_pop (tree_on_heap, const_and_copies_stack);
+ dest = VEC_pop (tree, const_and_copies_stack);
if (dest == NULL)
break;
- prev_value = VEC_pop (tree_on_heap, const_and_copies_stack);
+ prev_value = VEC_pop (tree, const_and_copies_stack);
SSA_NAME_VALUE (dest) = prev_value;
}
}
-/* Similar to restore_vars_to_original_value, except that it restores
- CURRDEFS to its original value. */
-static void
-restore_currdefs_to_original_value (void)
+/* A trivial wrapper so that we can present the generic jump
+ threading code with a simple API for simplifying statements. */
+static tree
+simplify_stmt_for_jump_threading (tree stmt)
{
- /* Restore CURRDEFS to its original state. */
- while (VEC_length (tree_on_heap, block_defs_stack) > 0)
- {
- tree tmp = VEC_pop (tree_on_heap, block_defs_stack);
- tree saved_def, var;
+ return lookup_avail_expr (stmt, false);
+}
- if (tmp == NULL_TREE)
- break;
+/* Wrapper for common code to attempt to thread an edge. For example,
+ it handles lazily building the dummy condition and the bookkeeping
+ when jump threading is successful. */
- /* If we recorded an SSA_NAME, then make the SSA_NAME the current
- definition of its underlying variable. If we recorded anything
- else, it must have been an _DECL node and its current reaching
- definition must have been NULL. */
- if (TREE_CODE (tmp) == SSA_NAME)
- {
- saved_def = tmp;
- var = SSA_NAME_VAR (saved_def);
- }
- else
- {
- saved_def = NULL;
- var = tmp;
- }
-
- var_ann (var)->current_def = saved_def;
+static void
+dom_thread_across_edge (struct dom_walk_data *walk_data, edge e)
+{
+ /* If we don't already have a dummy condition, build it now. */
+ if (! walk_data->global_data)
+ {
+ tree dummy_cond = build2 (NE, boolean_type_node,
+ integer_zero_node, integer_zero_node);
+ dummy_cond = build3 (COND_EXPR, void_type_node, dummy_cond, NULL, NULL);
+ walk_data->global_data = dummy_cond;
}
+
+ thread_across_edge (walk_data->global_data, e, false,
+ &const_and_copies_stack,
+ simplify_stmt_for_jump_threading);
}
/* We have finished processing the dominator children of BB, perform
{
tree last;
- /* If we are at a leaf node in the dominator tree, see if we can thread
- the edge from BB through its successor.
- Do this before we remove entries from our equivalence tables. */
- if (EDGE_COUNT (bb->succs) == 1
- && (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0
- && (get_immediate_dominator (CDI_DOMINATORS, EDGE_SUCC (bb, 0)->dest) != bb
- || phi_nodes (EDGE_SUCC (bb, 0)->dest)))
-
+ /* If we have an outgoing edge to a block with multiple incoming and
+ outgoing edges, then we may be able to thread the edge. ie, we
+ may be able to statically determine which of the outgoing edges
+ will be traversed when the incoming edge from BB is traversed. */
+ if (single_succ_p (bb)
+ && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0
+ && potentially_threadable_block (single_succ (bb)))
{
- thread_across_edge (walk_data, EDGE_SUCC (bb, 0));
+ dom_thread_across_edge (walk_data, single_succ_edge (bb));
}
else if ((last = last_stmt (bb))
&& TREE_CODE (last) == COND_EXPR
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
- /* If the THEN arm is the end of a dominator tree or has PHI nodes,
- then try to thread through its edge. */
- if (get_immediate_dominator (CDI_DOMINATORS, true_edge->dest) != bb
- || phi_nodes (true_edge->dest))
+ /* Only try to thread the edge if it reaches a target block with
+ more than one predecessor and more than one successor. */
+ if (potentially_threadable_block (true_edge->dest))
{
struct edge_info *edge_info;
unsigned int i;
/* Push a marker onto the available expression stack so that we
unwind any expressions related to the TRUE arm before processing
the false arm below. */
- VEC_safe_push (tree_on_heap, avail_exprs_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, block_defs_stack, NULL_TREE);
- VEC_safe_push (tree_on_heap, const_and_copies_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
- edge_info = true_edge->aux;
+ edge_info = (struct edge_info *) true_edge->aux;
/* If we have info associated with this edge, record it into
our equivalency tables. */
tree lhs = edge_info->lhs;
tree rhs = edge_info->rhs;
- /* If we have a simple NAME = VALUE equivalency record it.
- Until the jump threading selection code improves, only
- do this if both the name and value are SSA_NAMEs with
- the same underlying variable to avoid missing threading
- opportunities. */
- if (lhs
- && TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME
- && TREE_CODE (edge_info->rhs) == SSA_NAME
- && SSA_NAME_VAR (lhs) == SSA_NAME_VAR (rhs))
+ /* If we have a simple NAME = VALUE equivalency record it. */
+ if (lhs && TREE_CODE (lhs) == SSA_NAME)
record_const_or_copy (lhs, rhs);
/* If we have 0 = COND or 1 = COND equivalences, record them
}
}
- /* Now thread the edge. */
- thread_across_edge (walk_data, true_edge);
+ dom_thread_across_edge (walk_data, true_edge);
/* And restore the various tables to their state before
we threaded this edge. */
remove_local_expressions_from_table ();
- restore_vars_to_original_value ();
- restore_currdefs_to_original_value ();
}
/* Similarly for the ELSE arm. */
- if (get_immediate_dominator (CDI_DOMINATORS, false_edge->dest) != bb
- || phi_nodes (false_edge->dest))
+ if (potentially_threadable_block (false_edge->dest))
{
struct edge_info *edge_info;
unsigned int i;
- edge_info = false_edge->aux;
+ VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE);
+ edge_info = (struct edge_info *) false_edge->aux;
/* If we have info associated with this edge, record it into
our equivalency tables. */
tree lhs = edge_info->lhs;
tree rhs = edge_info->rhs;
- /* If we have a simple NAME = VALUE equivalency record it.
- Until the jump threading selection code improves, only
- do this if both the name and value are SSA_NAMEs with
- the same underlying variable to avoid missing threading
- opportunities. */
- if (lhs
- && TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME)
+ /* If we have a simple NAME = VALUE equivalency record it. */
+ if (lhs && TREE_CODE (lhs) == SSA_NAME)
record_const_or_copy (lhs, rhs);
/* If we have 0 = COND or 1 = COND equivalences, record them
}
}
- thread_across_edge (walk_data, false_edge);
+ /* Now thread the edge. */
+ dom_thread_across_edge (walk_data, false_edge);
/* No need to remove local expressions from our tables
or restore vars to their original value as that will
remove_local_expressions_from_table ();
restore_nonzero_vars_to_original_value ();
restore_vars_to_original_value ();
- restore_currdefs_to_original_value ();
-
- /* Remove VRP records associated with this basic block. They are no
- longer valid.
-
- To be efficient, we note which variables have had their values
- constrained in this block. So walk over each variable in the
- VRP_VARIABLEs array. */
- while (VEC_length (tree_on_heap, vrp_variables_stack) > 0)
- {
- tree var = VEC_pop (tree_on_heap, vrp_variables_stack);
- struct vrp_hash_elt vrp_hash_elt, *vrp_hash_elt_p;
- void **slot;
-
- /* Each variable has a stack of value range records. We want to
- invalidate those associated with our basic block. So we walk
- the array backwards popping off records associated with our
- block. Once we hit a record not associated with our block
- we are done. */
- varray_type var_vrp_records;
-
- if (var == NULL)
- break;
-
- vrp_hash_elt.var = var;
- vrp_hash_elt.records = NULL;
-
- slot = htab_find_slot (vrp_data, &vrp_hash_elt, NO_INSERT);
-
- vrp_hash_elt_p = (struct vrp_hash_elt *) *slot;
- var_vrp_records = vrp_hash_elt_p->records;
-
- while (VARRAY_ACTIVE_SIZE (var_vrp_records) > 0)
- {
- struct vrp_element *element
- = (struct vrp_element *)VARRAY_TOP_GENERIC_PTR (var_vrp_records);
-
- if (element->bb != bb)
- break;
-
- VARRAY_POP (var_vrp_records);
- }
- }
/* If we queued any statements to rescan in this block, then
go ahead and rescan them now. */
- while (VEC_length (tree_on_heap, stmts_to_rescan) > 0)
+ while (VEC_length (tree, stmts_to_rescan) > 0)
{
- tree stmt = VEC_last (tree_on_heap, stmts_to_rescan);
+ tree stmt = VEC_last (tree, stmts_to_rescan);
basic_block stmt_bb = bb_for_stmt (stmt);
if (stmt_bb != bb)
break;
- VEC_pop (tree_on_heap, stmts_to_rescan);
- mark_new_vars_to_rename (stmt, vars_to_rename);
+ VEC_pop (tree, stmts_to_rescan);
+ mark_new_vars_to_rename (stmt);
}
}
if (i == PHI_NUM_ARGS (phi))
bitmap_set_bit (nonzero_vars, SSA_NAME_VERSION (PHI_RESULT (phi)));
-
- register_new_def (lhs, &block_defs_stack);
}
}
{
unsigned int i;
- edge_info = e->aux;
+ edge_info = (struct edge_info *) e->aux;
if (edge_info)
{
if (cond_equivalences)
{
- bool recorded_range = false;
for (i = 0; i < edge_info->max_cond_equivalences; i += 2)
{
tree expr = cond_equivalences[i];
tree value = cond_equivalences[i + 1];
record_cond (expr, value);
-
- /* For the first true equivalence, record range
- information. We only do this for the first
- true equivalence as it should dominate any
- later true equivalences. */
- if (! recorded_range
- && COMPARISON_CLASS_P (expr)
- && value == boolean_true_node
- && TREE_CONSTANT (TREE_OPERAND (expr, 1)))
- {
- record_range (expr, bb);
- recorded_range = true;
- }
}
}
}
fprintf (file, " Redundant expressions eliminated: %6ld (%.0f%%)\n",
opt_stats.num_re, PERCENT (opt_stats.num_re,
n_exprs));
+ fprintf (file, " Constants propagated: %6ld\n",
+ opt_stats.num_const_prop);
+ fprintf (file, " Copies propagated: %6ld\n",
+ opt_stats.num_copy_prop);
fprintf (file, "\nHash table statistics:\n");
/* Record this SSA_NAME so that we can reset the global table
when we leave this block. */
- VEC_safe_push (tree_on_heap, nonzero_vars_stack, var);
+ VEC_safe_push (tree, heap, nonzero_vars_stack, var);
}
/* Enter a statement into the true/false expression hash table indicating
static void
record_cond (tree cond, tree value)
{
- struct expr_hash_elt *element = xmalloc (sizeof (struct expr_hash_elt));
+ struct expr_hash_elt *element = XCNEW (struct expr_hash_elt);
void **slot;
initialize_hash_element (cond, value, element);
if (*slot == NULL)
{
*slot = (void *) element;
- VEC_safe_push (tree_on_heap, avail_exprs_stack, cond);
+ VEC_safe_push (tree, heap, avail_exprs_stack, cond);
}
else
free (element);
case LT_EXPR:
case GT_EXPR:
edge_info->max_cond_equivalences = 12;
- edge_info->cond_equivalences = xmalloc (12 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 12);
build_and_record_new_cond ((TREE_CODE (cond) == LT_EXPR
? LE_EXPR : GE_EXPR),
op0, op1, &edge_info->cond_equivalences[4]);
case GE_EXPR:
case LE_EXPR:
edge_info->max_cond_equivalences = 6;
- edge_info->cond_equivalences = xmalloc (6 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 6);
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
&edge_info->cond_equivalences[4]);
break;
case EQ_EXPR:
edge_info->max_cond_equivalences = 10;
- edge_info->cond_equivalences = xmalloc (10 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 10);
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
&edge_info->cond_equivalences[4]);
build_and_record_new_cond (LE_EXPR, op0, op1,
case UNORDERED_EXPR:
edge_info->max_cond_equivalences = 16;
- edge_info->cond_equivalences = xmalloc (16 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 16);
build_and_record_new_cond (NE_EXPR, op0, op1,
&edge_info->cond_equivalences[4]);
build_and_record_new_cond (UNLE_EXPR, op0, op1,
case UNLT_EXPR:
case UNGT_EXPR:
edge_info->max_cond_equivalences = 8;
- edge_info->cond_equivalences = xmalloc (8 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 8);
build_and_record_new_cond ((TREE_CODE (cond) == UNLT_EXPR
? UNLE_EXPR : UNGE_EXPR),
op0, op1, &edge_info->cond_equivalences[4]);
case UNEQ_EXPR:
edge_info->max_cond_equivalences = 8;
- edge_info->cond_equivalences = xmalloc (8 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 8);
build_and_record_new_cond (UNLE_EXPR, op0, op1,
&edge_info->cond_equivalences[4]);
build_and_record_new_cond (UNGE_EXPR, op0, op1,
case LTGT_EXPR:
edge_info->max_cond_equivalences = 8;
- edge_info->cond_equivalences = xmalloc (8 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 8);
build_and_record_new_cond (NE_EXPR, op0, op1,
&edge_info->cond_equivalences[4]);
build_and_record_new_cond (ORDERED_EXPR, op0, op1,
default:
edge_info->max_cond_equivalences = 4;
- edge_info->cond_equivalences = xmalloc (4 * sizeof (tree));
+ edge_info->cond_equivalences = XNEWVEC (tree, 4);
break;
}
{
SSA_NAME_VALUE (x) = y;
- VEC_safe_push (tree_on_heap, const_and_copies_stack, prev_x);
- VEC_safe_push (tree_on_heap, const_and_copies_stack, x);
+ VEC_reserve (tree, heap, const_and_copies_stack, 2);
+ VEC_quick_push (tree, const_and_copies_stack, prev_x);
+ VEC_quick_push (tree, const_and_copies_stack, x);
}
will be relatively correct, and as more passes are taught to keep loop info
up to date, the result will become more and more accurate. */
-static int
+int
loop_depth_of_name (tree x)
{
tree defstmt;
return false;
}
-/* STMT is a MODIFY_EXPR for which we were unable to find RHS in the
- hash tables. Try to simplify the RHS using whatever equivalences
- we may have recorded.
-
- If we are able to simplify the RHS, then lookup the simplified form in
- the hash table and return the result. Otherwise return NULL. */
-
-static tree
-simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *walk_data,
- tree stmt, int insert)
-{
- tree rhs = TREE_OPERAND (stmt, 1);
- enum tree_code rhs_code = TREE_CODE (rhs);
- tree result = NULL;
-
- /* If we have lhs = ~x, look and see if we earlier had x = ~y.
- In which case we can change this statement to be lhs = y.
- Which can then be copy propagated.
-
- Similarly for negation. */
- if ((rhs_code == BIT_NOT_EXPR || rhs_code == NEGATE_EXPR)
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
- {
- /* Get the definition statement for our RHS. */
- tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
-
- /* See if the RHS_DEF_STMT has the same form as our statement. */
- if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR
- && TREE_CODE (TREE_OPERAND (rhs_def_stmt, 1)) == rhs_code)
- {
- tree rhs_def_operand;
-
- rhs_def_operand = TREE_OPERAND (TREE_OPERAND (rhs_def_stmt, 1), 0);
-
- /* Verify that RHS_DEF_OPERAND is a suitable SSA variable. */
- if (TREE_CODE (rhs_def_operand) == SSA_NAME
- && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
- result = update_rhs_and_lookup_avail_expr (stmt,
- rhs_def_operand,
- insert);
- }
- }
-
- /* If we have z = (x OP C1), see if we earlier had x = y OP C2.
- If OP is associative, create and fold (y OP C2) OP C1 which
- should result in (y OP C3), use that as the RHS for the
- assignment. Add minus to this, as we handle it specially below. */
- if ((associative_tree_code (rhs_code) || rhs_code == MINUS_EXPR)
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
- && is_gimple_min_invariant (TREE_OPERAND (rhs, 1)))
- {
- tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
-
- /* If the statement defines an induction variable, do not propagate
- its value, so that we do not create overlapping life ranges. */
- if (simple_iv_increment_p (rhs_def_stmt))
- goto dont_fold_assoc;
-
- /* See if the RHS_DEF_STMT has the same form as our statement. */
- if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR)
- {
- tree rhs_def_rhs = TREE_OPERAND (rhs_def_stmt, 1);
- enum tree_code rhs_def_code = TREE_CODE (rhs_def_rhs);
-
- if ((rhs_code == rhs_def_code && unsafe_associative_fp_binop (rhs))
- || (rhs_code == PLUS_EXPR && rhs_def_code == MINUS_EXPR)
- || (rhs_code == MINUS_EXPR && rhs_def_code == PLUS_EXPR))
- {
- tree def_stmt_op0 = TREE_OPERAND (rhs_def_rhs, 0);
- tree def_stmt_op1 = TREE_OPERAND (rhs_def_rhs, 1);
-
- if (TREE_CODE (def_stmt_op0) == SSA_NAME
- && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def_stmt_op0)
- && is_gimple_min_invariant (def_stmt_op1))
- {
- tree outer_const = TREE_OPERAND (rhs, 1);
- tree type = TREE_TYPE (TREE_OPERAND (stmt, 0));
- tree t;
-
- /* If we care about correct floating point results, then
- don't fold x + c1 - c2. Note that we need to take both
- the codes and the signs to figure this out. */
- if (FLOAT_TYPE_P (type)
- && !flag_unsafe_math_optimizations
- && (rhs_def_code == PLUS_EXPR
- || rhs_def_code == MINUS_EXPR))
- {
- bool neg = false;
-
- neg ^= (rhs_code == MINUS_EXPR);
- neg ^= (rhs_def_code == MINUS_EXPR);
- neg ^= real_isneg (TREE_REAL_CST_PTR (outer_const));
- neg ^= real_isneg (TREE_REAL_CST_PTR (def_stmt_op1));
-
- if (neg)
- goto dont_fold_assoc;
- }
-
- /* Ho hum. So fold will only operate on the outermost
- thingy that we give it, so we have to build the new
- expression in two pieces. This requires that we handle
- combinations of plus and minus. */
- if (rhs_def_code != rhs_code)
- {
- if (rhs_def_code == MINUS_EXPR)
- t = build (MINUS_EXPR, type, outer_const, def_stmt_op1);
- else
- t = build (MINUS_EXPR, type, def_stmt_op1, outer_const);
- rhs_code = PLUS_EXPR;
- }
- else if (rhs_def_code == MINUS_EXPR)
- t = build (PLUS_EXPR, type, def_stmt_op1, outer_const);
- else
- t = build (rhs_def_code, type, def_stmt_op1, outer_const);
- t = local_fold (t);
- t = build (rhs_code, type, def_stmt_op0, t);
- t = local_fold (t);
-
- /* If the result is a suitable looking gimple expression,
- then use it instead of the original for STMT. */
- if (TREE_CODE (t) == SSA_NAME
- || (UNARY_CLASS_P (t)
- && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME)
- || ((BINARY_CLASS_P (t) || COMPARISON_CLASS_P (t))
- && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
- && is_gimple_val (TREE_OPERAND (t, 1))))
- result = update_rhs_and_lookup_avail_expr (stmt, t, insert);
- }
- }
- }
- dont_fold_assoc:;
- }
-
- /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
- and BIT_AND_EXPR respectively if the first operand is greater
- than zero and the second operand is an exact power of two. */
- if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
- && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
- && integer_pow2p (TREE_OPERAND (rhs, 1)))
- {
- tree val;
- tree op = TREE_OPERAND (rhs, 0);
-
- if (TYPE_UNSIGNED (TREE_TYPE (op)))
- {
- val = integer_one_node;
- }
- else
- {
- tree dummy_cond = walk_data->global_data;
-
- if (! dummy_cond)
- {
- dummy_cond = build (GT_EXPR, boolean_type_node,
- op, integer_zero_node);
- dummy_cond = build (COND_EXPR, void_type_node,
- dummy_cond, NULL, NULL);
- walk_data->global_data = dummy_cond;
- }
- else
- {
- TREE_SET_CODE (COND_EXPR_COND (dummy_cond), GT_EXPR);
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op;
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1)
- = integer_zero_node;
- }
- val = simplify_cond_and_lookup_avail_expr (dummy_cond, NULL, false);
- }
-
- if (val && integer_onep (val))
- {
- tree t;
- tree op0 = TREE_OPERAND (rhs, 0);
- tree op1 = TREE_OPERAND (rhs, 1);
-
- if (rhs_code == TRUNC_DIV_EXPR)
- t = build (RSHIFT_EXPR, TREE_TYPE (op0), op0,
- build_int_cst (NULL_TREE, tree_log2 (op1)));
- else
- t = build (BIT_AND_EXPR, TREE_TYPE (op0), op0,
- local_fold (build (MINUS_EXPR, TREE_TYPE (op1),
- op1, integer_one_node)));
-
- result = update_rhs_and_lookup_avail_expr (stmt, t, insert);
- }
- }
-
- /* Transform ABS (X) into X or -X as appropriate. */
- if (rhs_code == ABS_EXPR
- && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
- {
- tree val;
- tree op = TREE_OPERAND (rhs, 0);
- tree type = TREE_TYPE (op);
-
- if (TYPE_UNSIGNED (type))
- {
- val = integer_zero_node;
- }
- else
- {
- tree dummy_cond = walk_data->global_data;
-
- if (! dummy_cond)
- {
- dummy_cond = build (LE_EXPR, boolean_type_node,
- op, integer_zero_node);
- dummy_cond = build (COND_EXPR, void_type_node,
- dummy_cond, NULL, NULL);
- walk_data->global_data = dummy_cond;
- }
- else
- {
- TREE_SET_CODE (COND_EXPR_COND (dummy_cond), LE_EXPR);
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op;
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1)
- = build_int_cst (type, 0);
- }
- val = simplify_cond_and_lookup_avail_expr (dummy_cond, NULL, false);
-
- if (!val)
- {
- TREE_SET_CODE (COND_EXPR_COND (dummy_cond), GE_EXPR);
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op;
- TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1)
- = build_int_cst (type, 0);
-
- val = simplify_cond_and_lookup_avail_expr (dummy_cond,
- NULL, false);
-
- if (val)
- {
- if (integer_zerop (val))
- val = integer_one_node;
- else if (integer_onep (val))
- val = integer_zero_node;
- }
- }
- }
-
- if (val
- && (integer_onep (val) || integer_zerop (val)))
- {
- tree t;
-
- if (integer_onep (val))
- t = build1 (NEGATE_EXPR, TREE_TYPE (op), op);
- else
- t = op;
-
- result = update_rhs_and_lookup_avail_expr (stmt, t, insert);
- }
- }
-
- /* Optimize *"foo" into 'f'. This is done here rather than
- in fold to avoid problems with stuff like &*"foo". */
- if (TREE_CODE (rhs) == INDIRECT_REF || TREE_CODE (rhs) == ARRAY_REF)
- {
- tree t = fold_read_from_constant_string (rhs);
-
- if (t)
- result = update_rhs_and_lookup_avail_expr (stmt, t, insert);
- }
-
- return result;
-}
-
-/* COND is a condition of the form:
-
- x == const or x != const
-
- Look back to x's defining statement and see if x is defined as
-
- x = (type) y;
-
- If const is unchanged if we convert it to type, then we can build
- the equivalent expression:
-
-
- y == const or y != const
-
- Which may allow further optimizations.
-
- Return the equivalent comparison or NULL if no such equivalent comparison
- was found. */
-
-static tree
-find_equivalent_equality_comparison (tree cond)
-{
- tree op0 = TREE_OPERAND (cond, 0);
- tree op1 = TREE_OPERAND (cond, 1);
- tree def_stmt = SSA_NAME_DEF_STMT (op0);
-
- /* OP0 might have been a parameter, so first make sure it
- was defined by a MODIFY_EXPR. */
- if (def_stmt && TREE_CODE (def_stmt) == MODIFY_EXPR)
- {
- tree def_rhs = TREE_OPERAND (def_stmt, 1);
-
- /* Now make sure the RHS of the MODIFY_EXPR is a typecast. */
- if ((TREE_CODE (def_rhs) == NOP_EXPR
- || TREE_CODE (def_rhs) == CONVERT_EXPR)
- && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME)
- {
- tree def_rhs_inner = TREE_OPERAND (def_rhs, 0);
- tree def_rhs_inner_type = TREE_TYPE (def_rhs_inner);
- tree new;
-
- if (TYPE_PRECISION (def_rhs_inner_type)
- > TYPE_PRECISION (TREE_TYPE (def_rhs)))
- return NULL;
-
- /* What we want to prove is that if we convert OP1 to
- the type of the object inside the NOP_EXPR that the
- result is still equivalent to SRC.
-
- If that is true, the build and return new equivalent
- condition which uses the source of the typecast and the
- new constant (which has only changed its type). */
- new = build1 (TREE_CODE (def_rhs), def_rhs_inner_type, op1);
- new = local_fold (new);
- if (is_gimple_val (new) && tree_int_cst_equal (new, op1))
- return build (TREE_CODE (cond), TREE_TYPE (cond),
- def_rhs_inner, new);
- }
- }
- return NULL;
-}
-
-/* STMT is a COND_EXPR for which we could not trivially determine its
- result. This routine attempts to find equivalent forms of the
- condition which we may be able to optimize better. It also
- uses simple value range propagation to optimize conditionals. */
-
-static tree
-simplify_cond_and_lookup_avail_expr (tree stmt,
- stmt_ann_t ann,
- int insert)
-{
- tree cond = COND_EXPR_COND (stmt);
-
- if (COMPARISON_CLASS_P (cond))
- {
- tree op0 = TREE_OPERAND (cond, 0);
- tree op1 = TREE_OPERAND (cond, 1);
-
- if (TREE_CODE (op0) == SSA_NAME && is_gimple_min_invariant (op1))
- {
- int limit;
- tree low, high, cond_low, cond_high;
- int lowequal, highequal, swapped, no_overlap, subset, cond_inverted;
- varray_type vrp_records;
- struct vrp_element *element;
- struct vrp_hash_elt vrp_hash_elt, *vrp_hash_elt_p;
- void **slot;
-
- /* First see if we have test of an SSA_NAME against a constant
- where the SSA_NAME is defined by an earlier typecast which
- is irrelevant when performing tests against the given
- constant. */
- if (TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
- {
- tree new_cond = find_equivalent_equality_comparison (cond);
-
- if (new_cond)
- {
- /* Update the statement to use the new equivalent
- condition. */
- COND_EXPR_COND (stmt) = new_cond;
-
- /* If this is not a real stmt, ann will be NULL and we
- avoid processing the operands. */
- if (ann)
- modify_stmt (stmt);
-
- /* Lookup the condition and return its known value if it
- exists. */
- new_cond = lookup_avail_expr (stmt, insert);
- if (new_cond)
- return new_cond;
-
- /* The operands have changed, so update op0 and op1. */
- op0 = TREE_OPERAND (cond, 0);
- op1 = TREE_OPERAND (cond, 1);
- }
- }
-
- /* Consult the value range records for this variable (if they exist)
- to see if we can eliminate or simplify this conditional.
-
- Note two tests are necessary to determine no records exist.
- First we have to see if the virtual array exists, if it
- exists, then we have to check its active size.
-
- Also note the vast majority of conditionals are not testing
- a variable which has had its range constrained by an earlier
- conditional. So this filter avoids a lot of unnecessary work. */
- vrp_hash_elt.var = op0;
- vrp_hash_elt.records = NULL;
- slot = htab_find_slot (vrp_data, &vrp_hash_elt, NO_INSERT);
- if (slot == NULL)
- return NULL;
-
- vrp_hash_elt_p = (struct vrp_hash_elt *) *slot;
- vrp_records = vrp_hash_elt_p->records;
- if (vrp_records == NULL)
- return NULL;
-
- limit = VARRAY_ACTIVE_SIZE (vrp_records);
-
- /* If we have no value range records for this variable, or we are
- unable to extract a range for this condition, then there is
- nothing to do. */
- if (limit == 0
- || ! extract_range_from_cond (cond, &cond_high,
- &cond_low, &cond_inverted))
- return NULL;
-
- /* We really want to avoid unnecessary computations of range
- info. So all ranges are computed lazily; this avoids a
- lot of unnecessary work. i.e., we record the conditional,
- but do not process how it constrains the variable's
- potential values until we know that processing the condition
- could be helpful.
-
- However, we do not want to have to walk a potentially long
- list of ranges, nor do we want to compute a variable's
- range more than once for a given path.
-
- Luckily, each time we encounter a conditional that can not
- be otherwise optimized we will end up here and we will
- compute the necessary range information for the variable
- used in this condition.
-
- Thus you can conclude that there will never be more than one
- conditional associated with a variable which has not been
- processed. So we never need to merge more than one new
- conditional into the current range.
-
- These properties also help us avoid unnecessary work. */
- element
- = (struct vrp_element *)VARRAY_GENERIC_PTR (vrp_records, limit - 1);
-
- if (element->high && element->low)
- {
- /* The last element has been processed, so there is no range
- merging to do, we can simply use the high/low values
- recorded in the last element. */
- low = element->low;
- high = element->high;
- }
- else
- {
- tree tmp_high, tmp_low;
- int dummy;
-
- /* The last element has not been processed. Process it now.
- record_range should ensure for cond inverted is not set.
- This call can only fail if cond is x < min or x > max,
- which fold should have optimized into false.
- If that doesn't happen, just pretend all values are
- in the range. */
- if (! extract_range_from_cond (element->cond, &tmp_high,
- &tmp_low, &dummy))
- gcc_unreachable ();
- else
- gcc_assert (dummy == 0);
-
- /* If this is the only element, then no merging is necessary,
- the high/low values from extract_range_from_cond are all
- we need. */
- if (limit == 1)
- {
- low = tmp_low;
- high = tmp_high;
- }
- else
- {
- /* Get the high/low value from the previous element. */
- struct vrp_element *prev
- = (struct vrp_element *)VARRAY_GENERIC_PTR (vrp_records,
- limit - 2);
- low = prev->low;
- high = prev->high;
-
- /* Merge in this element's range with the range from the
- previous element.
-
- The low value for the merged range is the maximum of
- the previous low value and the low value of this record.
-
- Similarly the high value for the merged range is the
- minimum of the previous high value and the high value of
- this record. */
- low = (tree_int_cst_compare (low, tmp_low) == 1
- ? low : tmp_low);
- high = (tree_int_cst_compare (high, tmp_high) == -1
- ? high : tmp_high);
- }
-
- /* And record the computed range. */
- element->low = low;
- element->high = high;
-
- }
-
- /* After we have constrained this variable's potential values,
- we try to determine the result of the given conditional.
-
- To simplify later tests, first determine if the current
- low value is the same low value as the conditional.
- Similarly for the current high value and the high value
- for the conditional. */
- lowequal = tree_int_cst_equal (low, cond_low);
- highequal = tree_int_cst_equal (high, cond_high);
-
- if (lowequal && highequal)
- return (cond_inverted ? boolean_false_node : boolean_true_node);
-
- /* To simplify the overlap/subset tests below we may want
- to swap the two ranges so that the larger of the two
- ranges occurs "first". */
- swapped = 0;
- if (tree_int_cst_compare (low, cond_low) == 1
- || (lowequal
- && tree_int_cst_compare (cond_high, high) == 1))
- {
- tree temp;
-
- swapped = 1;
- temp = low;
- low = cond_low;
- cond_low = temp;
- temp = high;
- high = cond_high;
- cond_high = temp;
- }
-
- /* Now determine if there is no overlap in the ranges
- or if the second range is a subset of the first range. */
- no_overlap = tree_int_cst_lt (high, cond_low);
- subset = tree_int_cst_compare (cond_high, high) != 1;
-
- /* If there was no overlap in the ranges, then this conditional
- always has a false value (unless we had to invert this
- conditional, in which case it always has a true value). */
- if (no_overlap)
- return (cond_inverted ? boolean_true_node : boolean_false_node);
-
- /* If the current range is a subset of the condition's range,
- then this conditional always has a true value (unless we
- had to invert this conditional, in which case it always
- has a true value). */
- if (subset && swapped)
- return (cond_inverted ? boolean_false_node : boolean_true_node);
-
- /* We were unable to determine the result of the conditional.
- However, we may be able to simplify the conditional. First
- merge the ranges in the same manner as range merging above. */
- low = tree_int_cst_compare (low, cond_low) == 1 ? low : cond_low;
- high = tree_int_cst_compare (high, cond_high) == -1 ? high : cond_high;
-
- /* If the range has converged to a single point, then turn this
- into an equality comparison. */
- if (TREE_CODE (cond) != EQ_EXPR
- && TREE_CODE (cond) != NE_EXPR
- && tree_int_cst_equal (low, high))
- {
- TREE_SET_CODE (cond, EQ_EXPR);
- TREE_OPERAND (cond, 1) = high;
- }
- }
- }
- return 0;
-}
-
-/* STMT is a SWITCH_EXPR for which we could not trivially determine its
- result. This routine attempts to find equivalent forms of the
- condition which we may be able to optimize better. */
-
-static tree
-simplify_switch_and_lookup_avail_expr (tree stmt, int insert)
-{
- tree cond = SWITCH_COND (stmt);
- tree def, to, ti;
-
- /* The optimization that we really care about is removing unnecessary
- casts. That will let us do much better in propagating the inferred
- constant at the switch target. */
- if (TREE_CODE (cond) == SSA_NAME)
- {
- def = SSA_NAME_DEF_STMT (cond);
- if (TREE_CODE (def) == MODIFY_EXPR)
- {
- def = TREE_OPERAND (def, 1);
- if (TREE_CODE (def) == NOP_EXPR)
- {
- int need_precision;
- bool fail;
-
- def = TREE_OPERAND (def, 0);
-
-#ifdef ENABLE_CHECKING
- /* ??? Why was Jeff testing this? We are gimple... */
- gcc_assert (is_gimple_val (def));
-#endif
-
- to = TREE_TYPE (cond);
- ti = TREE_TYPE (def);
-
- /* If we have an extension that preserves value, then we
- can copy the source value into the switch. */
-
- need_precision = TYPE_PRECISION (ti);
- fail = false;
- if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
- fail = true;
- else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
- need_precision += 1;
- if (TYPE_PRECISION (to) < need_precision)
- fail = true;
-
- if (!fail)
- {
- SWITCH_COND (stmt) = def;
- modify_stmt (stmt);
-
- return lookup_avail_expr (stmt, insert);
- }
- }
- }
- }
-
- return 0;
-}
-
-
/* CONST_AND_COPIES is a table which maps an SSA_NAME to the current
known value for that SSA_NAME (or NULL if no value is known).
edge e;
edge_iterator ei;
- /* This can get rather expensive if the implementation is naive in
- how it finds the phi alternative associated with a particular edge. */
FOR_EACH_EDGE (e, ei, bb->succs)
{
tree phi;
ORIG_P with its value in our constant/copy table. */
new = SSA_NAME_VALUE (orig);
if (new
+ && new != orig
&& (TREE_CODE (new) == SSA_NAME
|| is_gimple_min_invariant (new))
&& may_propagate_copy (orig, new))
- {
- propagate_value (orig_p, new);
- }
+ propagate_value (orig_p, new);
}
}
}
{
tree labels = SWITCH_LABELS (stmt);
int i, n_labels = TREE_VEC_LENGTH (labels);
- tree *info = xcalloc (n_basic_blocks, sizeof (tree));
+ tree *info = XCNEWVEC (tree, last_basic_block);
edge e;
edge_iterator ei;
propagate_to_outgoing_edges (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
basic_block bb)
{
-
record_edge_info (bb);
cprop_into_successor_phis (bb, nonzero_vars);
}
table. */
static bool
-eliminate_redundant_computations (struct dom_walk_data *walk_data,
- tree stmt, stmt_ann_t ann)
+eliminate_redundant_computations (tree stmt)
{
- v_may_def_optype v_may_defs = V_MAY_DEF_OPS (ann);
tree *expr_p, def = NULL_TREE;
bool insert = true;
tree cached_lhs;
bool retval = false;
+ bool modify_expr_p = false;
if (TREE_CODE (stmt) == MODIFY_EXPR)
def = TREE_OPERAND (stmt, 0);
/* Certain expressions on the RHS can be optimized away, but can not
themselves be entered into the hash tables. */
- if (ann->makes_aliased_stores
- || ! def
+ if (! def
|| TREE_CODE (def) != SSA_NAME
|| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
- || NUM_V_MAY_DEFS (v_may_defs) != 0
+ || !ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF)
/* Do not record equivalences for increments of ivs. This would create
overlapping live ranges for a very questionable gain. */
|| simple_iv_increment_p (stmt))
/* Check if the expression has been computed before. */
cached_lhs = lookup_avail_expr (stmt, insert);
- /* If this is an assignment and the RHS was not in the hash table,
- then try to simplify the RHS and lookup the new RHS in the
- hash table. */
- if (! cached_lhs && TREE_CODE (stmt) == MODIFY_EXPR)
- cached_lhs = simplify_rhs_and_lookup_avail_expr (walk_data, stmt, insert);
- /* Similarly if this is a COND_EXPR and we did not find its
- expression in the hash table, simplify the condition and
- try again. */
- else if (! cached_lhs && TREE_CODE (stmt) == COND_EXPR)
- cached_lhs = simplify_cond_and_lookup_avail_expr (stmt, ann, insert);
- /* Similarly for a SWITCH_EXPR. */
- else if (!cached_lhs && TREE_CODE (stmt) == SWITCH_EXPR)
- cached_lhs = simplify_switch_and_lookup_avail_expr (stmt, insert);
-
opt_stats.num_exprs_considered++;
/* Get a pointer to the expression we are trying to optimize. */
else if (TREE_CODE (stmt) == SWITCH_EXPR)
expr_p = &SWITCH_COND (stmt);
else if (TREE_CODE (stmt) == RETURN_EXPR && TREE_OPERAND (stmt, 0))
- expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1);
+ {
+ expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1);
+ modify_expr_p = true;
+ }
else
- expr_p = &TREE_OPERAND (stmt, 1);
+ {
+ expr_p = &TREE_OPERAND (stmt, 1);
+ modify_expr_p = true;
+ }
/* It is safe to ignore types here since we have already done
type checking in the hashing and equality routines. In fact
propagation. Also, make sure that it is safe to propagate
CACHED_LHS into *EXPR_P. */
if (cached_lhs
- && (TREE_CODE (cached_lhs) != SSA_NAME
+ && ((TREE_CODE (cached_lhs) != SSA_NAME
+ && (modify_expr_p
+ || tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
+ TREE_TYPE (cached_lhs))))
|| may_propagate_copy (*expr_p, cached_lhs)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
|| (POINTER_TYPE_P (TREE_TYPE (*expr_p))
&& is_gimple_min_invariant (cached_lhs)))
retval = true;
+
+ if (modify_expr_p
+ && !tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p),
+ TREE_TYPE (cached_lhs)))
+ cached_lhs = fold_convert (TREE_TYPE (*expr_p), cached_lhs);
propagate_tree_value (expr_p, cached_lhs);
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
}
return retval;
}
|| is_gimple_min_invariant (rhs)))
SSA_NAME_VALUE (lhs) = rhs;
- /* alloca never returns zero and the address of a non-weak symbol
- is never zero. NOP_EXPRs and CONVERT_EXPRs can be completely
- stripped as they do not affect this equivalence. */
- while (TREE_CODE (rhs) == NOP_EXPR
- || TREE_CODE (rhs) == CONVERT_EXPR)
- rhs = TREE_OPERAND (rhs, 0);
-
- if (alloca_call_p (rhs)
- || (TREE_CODE (rhs) == ADDR_EXPR
- && DECL_P (TREE_OPERAND (rhs, 0))
- && ! DECL_WEAK (TREE_OPERAND (rhs, 0))))
- record_var_is_nonzero (lhs);
-
- /* IOR of any value with a nonzero value will result in a nonzero
- value. Even if we do not know the exact result recording that
- the result is nonzero is worth the effort. */
- if (TREE_CODE (rhs) == BIT_IOR_EXPR
- && integer_nonzerop (TREE_OPERAND (rhs, 1)))
+ if (tree_expr_nonzero_p (rhs))
record_var_is_nonzero (lhs);
}
if (rhs)
{
/* Build a new statement with the RHS and LHS exchanged. */
- new = build (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs);
+ new = build2 (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs);
- create_ssa_artficial_load_stmt (&(ann->operands), new);
+ create_ssa_artficial_load_stmt (new, stmt);
/* Finally enter the statement into the available expression
table. */
copy of some other variable, use the value or copy stored in
CONST_AND_COPIES. */
val = SSA_NAME_VALUE (op);
- if (val && TREE_CODE (val) != VALUE_HANDLE)
+ if (val && val != op && TREE_CODE (val) != VALUE_HANDLE)
{
tree op_type, val_type;
statement. Also only allow the new value to be an SSA_NAME
for propagation into virtual operands. */
if (!is_gimple_reg (op)
- && (get_virtual_var (val) != get_virtual_var (op)
- || TREE_CODE (val) != SSA_NAME))
+ && (TREE_CODE (val) != SSA_NAME
+ || is_gimple_reg (val)
+ || get_virtual_var (val) != get_virtual_var (op)))
return false;
/* Do not replace hard register operands in asm statements. */
&& is_gimple_min_invariant (val)))
may_have_exposed_new_symbols = true;
+ if (TREE_CODE (val) != SSA_NAME)
+ opt_stats.num_const_prop++;
+ else
+ opt_stats.num_copy_prop++;
+
propagate_value (op_p, val);
/* And note that we modified this statement. This is now
safe, even if we changed virtual operands since we will
rescan the statement and rewrite its operands again. */
- modify_stmt (stmt);
+ mark_stmt_modified (stmt);
}
return may_have_exposed_new_symbols;
}
bool may_have_exposed_new_symbols = false;
use_operand_p op_p;
ssa_op_iter iter;
- tree rhs;
FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES)
{
may_have_exposed_new_symbols |= cprop_operand (stmt, op_p);
}
- if (may_have_exposed_new_symbols)
- {
- rhs = get_rhs (stmt);
- if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
- recompute_tree_invarant_for_addr_expr (rhs);
- }
-
return may_have_exposed_new_symbols;
}
-/* Optimize the statement pointed by iterator SI.
+/* Optimize the statement pointed to by iterator SI.
We try to perform some simplistic global redundancy elimination and
constant propagation:
the variable in the LHS in the CONST_AND_COPIES table. */
static void
-optimize_stmt (struct dom_walk_data *walk_data, basic_block bb,
- block_stmt_iterator si)
+optimize_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
+ basic_block bb, block_stmt_iterator si)
{
stmt_ann_t ann;
- tree stmt;
+ tree stmt, old_stmt;
bool may_optimize_p;
bool may_have_exposed_new_symbols = false;
- stmt = bsi_stmt (si);
-
- get_stmt_operands (stmt);
+ old_stmt = stmt = bsi_stmt (si);
+
+ if (TREE_CODE (stmt) == COND_EXPR)
+ canonicalize_comparison (stmt);
+
+ update_stmt_if_modified (stmt);
ann = stmt_ann (stmt);
opt_stats.num_stmts++;
may_have_exposed_new_symbols = false;
fold its RHS before checking for redundant computations. */
if (ann->modified)
{
+ tree rhs;
+
/* Try to fold the statement making sure that STMT is kept
up to date. */
if (fold_stmt (bsi_stmt_ptr (si)))
}
}
+ rhs = get_rhs (stmt);
+ if (rhs && TREE_CODE (rhs) == ADDR_EXPR)
+ recompute_tree_invariant_for_addr_expr (rhs);
+
/* Constant/copy propagation above may change the set of
virtual operands associated with this statement. Folding
may remove the need for some virtual operands.
|| TREE_CODE (stmt) == SWITCH_EXPR));
if (may_optimize_p)
- may_have_exposed_new_symbols
- |= eliminate_redundant_computations (walk_data, stmt, ann);
+ may_have_exposed_new_symbols |= eliminate_redundant_computations (stmt);
/* Record any additional equivalences created by this statement. */
if (TREE_CODE (stmt) == MODIFY_EXPR)
may_optimize_p,
ann);
- register_definitions_for_stmt (stmt);
-
/* If STMT is a COND_EXPR and it was modified, then we may know
where it goes. If that is the case, then mark the CFG as altered.
/* If we simplified a statement in such a way as to be shown that it
cannot trap, update the eh information and the cfg to match. */
- if (maybe_clean_eh_stmt (stmt))
+ if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
{
bitmap_set_bit (need_eh_cleanup, bb->index);
if (dump_file && (dump_flags & TDF_DETAILS))
}
if (may_have_exposed_new_symbols)
- VEC_safe_push (tree_on_heap, stmts_to_rescan, bsi_stmt (si));
-}
-
-/* Replace the RHS of STMT with NEW_RHS. If RHS can be found in the
- available expression hashtable, then return the LHS from the hash
- table.
-
- If INSERT is true, then we also update the available expression
- hash table to account for the changes made to STMT. */
-
-static tree
-update_rhs_and_lookup_avail_expr (tree stmt, tree new_rhs, bool insert)
-{
- tree cached_lhs = NULL;
-
- /* Remove the old entry from the hash table. */
- if (insert)
- {
- struct expr_hash_elt element;
-
- initialize_hash_element (stmt, NULL, &element);
- htab_remove_elt_with_hash (avail_exprs, &element, element.hash);
- }
-
- /* Now update the RHS of the assignment. */
- TREE_OPERAND (stmt, 1) = new_rhs;
-
- /* Now lookup the updated statement in the hash table. */
- cached_lhs = lookup_avail_expr (stmt, insert);
-
- /* We have now called lookup_avail_expr twice with two different
- versions of this same statement, once in optimize_stmt, once here.
-
- We know the call in optimize_stmt did not find an existing entry
- in the hash table, so a new entry was created. At the same time
- this statement was pushed onto the AVAIL_EXPRS_STACK vector.
-
- If this call failed to find an existing entry on the hash table,
- then the new version of this statement was entered into the
- hash table. And this statement was pushed onto BLOCK_AVAIL_EXPR
- for the second time. So there are two copies on BLOCK_AVAIL_EXPRs
-
- If this call succeeded, we still have one copy of this statement
- on the BLOCK_AVAIL_EXPRs vector.
-
- For both cases, we need to pop the most recent entry off the
- BLOCK_AVAIL_EXPRs vector. For the case where we never found this
- statement in the hash tables, that will leave precisely one
- copy of this statement on BLOCK_AVAIL_EXPRs. For the case where
- we found a copy of this statement in the second hash table lookup
- we want _no_ copies of this statement in BLOCK_AVAIL_EXPRs. */
- if (insert)
- VEC_pop (tree_on_heap, avail_exprs_stack);
-
- /* And make sure we record the fact that we modified this
- statement. */
- modify_stmt (stmt);
-
- return cached_lhs;
+ VEC_safe_push (tree, heap, stmts_to_rescan, bsi_stmt (si));
}
/* Search for an existing instance of STMT in the AVAIL_EXPRS table. If
NULL_TREE.
Also, when an expression is first inserted in the AVAIL_EXPRS table, it
- is also added to the stack pointed by BLOCK_AVAIL_EXPRS_P, so that they
+ is also added to the stack pointed to by BLOCK_AVAIL_EXPRS_P, so that they
can be removed when we finish processing this block and its children.
NOTE: This function assumes that STMT is a MODIFY_EXPR node that
void **slot;
tree lhs;
tree temp;
- struct expr_hash_elt *element = xmalloc (sizeof (struct expr_hash_elt));
+ struct expr_hash_elt *element = XNEW (struct expr_hash_elt);
lhs = TREE_CODE (stmt) == MODIFY_EXPR ? TREE_OPERAND (stmt, 0) : NULL;
{
tree t = element->rhs;
free (element);
-
- if (TREE_CODE (t) == EQ_EXPR)
- return boolean_false_node;
- else
- return boolean_true_node;
+ return constant_boolean_node (TREE_CODE (t) != EQ_EXPR,
+ TREE_TYPE (t));
}
}
if (*slot == NULL)
{
*slot = (void *) element;
- VEC_safe_push (tree_on_heap, avail_exprs_stack,
+ VEC_safe_push (tree, heap, avail_exprs_stack,
stmt ? stmt : element->rhs);
return NULL_TREE;
}
return lhs;
}
-/* Given a condition COND, record into HI_P, LO_P and INVERTED_P the
- range of values that result in the conditional having a true value.
-
- Return true if we are successful in extracting a range from COND and
- false if we are unsuccessful. */
-
-static bool
-extract_range_from_cond (tree cond, tree *hi_p, tree *lo_p, int *inverted_p)
-{
- tree op1 = TREE_OPERAND (cond, 1);
- tree high, low, type;
- int inverted;
-
- type = TREE_TYPE (op1);
-
- /* Experiments have shown that it's rarely, if ever useful to
- record ranges for enumerations. Presumably this is due to
- the fact that they're rarely used directly. They are typically
- cast into an integer type and used that way. */
- if (TREE_CODE (type) != INTEGER_TYPE
- /* We don't know how to deal with types with variable bounds. */
- || TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
- || TREE_CODE (TYPE_MAX_VALUE (type)) != INTEGER_CST)
- return 0;
-
- switch (TREE_CODE (cond))
- {
- case EQ_EXPR:
- high = low = op1;
- inverted = 0;
- break;
-
- case NE_EXPR:
- high = low = op1;
- inverted = 1;
- break;
-
- case GE_EXPR:
- low = op1;
- high = TYPE_MAX_VALUE (type);
- inverted = 0;
- break;
-
- case GT_EXPR:
- high = TYPE_MAX_VALUE (type);
- if (!tree_int_cst_lt (op1, high))
- return 0;
- low = int_const_binop (PLUS_EXPR, op1, integer_one_node, 1);
- inverted = 0;
- break;
-
- case LE_EXPR:
- high = op1;
- low = TYPE_MIN_VALUE (type);
- inverted = 0;
- break;
-
- case LT_EXPR:
- low = TYPE_MIN_VALUE (type);
- if (!tree_int_cst_lt (low, op1))
- return 0;
- high = int_const_binop (MINUS_EXPR, op1, integer_one_node, 1);
- inverted = 0;
- break;
-
- default:
- return 0;
- }
-
- *hi_p = high;
- *lo_p = low;
- *inverted_p = inverted;
- return 1;
-}
-
-/* Record a range created by COND for basic block BB. */
-
-static void
-record_range (tree cond, basic_block bb)
-{
- enum tree_code code = TREE_CODE (cond);
-
- /* We explicitly ignore NE_EXPRs and all the unordered comparisons.
- They rarely allow for meaningful range optimizations and significantly
- complicate the implementation. */
- if ((code == LT_EXPR || code == LE_EXPR || code == GT_EXPR
- || code == GE_EXPR || code == EQ_EXPR)
- && TREE_CODE (TREE_TYPE (TREE_OPERAND (cond, 1))) == INTEGER_TYPE)
- {
- struct vrp_hash_elt *vrp_hash_elt;
- struct vrp_element *element;
- varray_type *vrp_records_p;
- void **slot;
-
-
- vrp_hash_elt = xmalloc (sizeof (struct vrp_hash_elt));
- vrp_hash_elt->var = TREE_OPERAND (cond, 0);
- vrp_hash_elt->records = NULL;
- slot = htab_find_slot (vrp_data, vrp_hash_elt, INSERT);
-
- if (*slot == NULL)
- *slot = (void *) vrp_hash_elt;
- else
- free (vrp_hash_elt);
-
- vrp_hash_elt = (struct vrp_hash_elt *) *slot;
- vrp_records_p = &vrp_hash_elt->records;
-
- element = ggc_alloc (sizeof (struct vrp_element));
- element->low = NULL;
- element->high = NULL;
- element->cond = cond;
- element->bb = bb;
-
- if (*vrp_records_p == NULL)
- VARRAY_GENERIC_PTR_INIT (*vrp_records_p, 2, "vrp records");
-
- VARRAY_PUSH_GENERIC_PTR (*vrp_records_p, element);
- VEC_safe_push (tree_on_heap, vrp_variables_stack, TREE_OPERAND (cond, 0));
- }
-}
-
-/* Hashing and equality functions for VRP_DATA.
-
- Since this hash table is addressed by SSA_NAMEs, we can hash on
- their version number and equality can be determined with a
- pointer comparison. */
-
-static hashval_t
-vrp_hash (const void *p)
-{
- tree var = ((struct vrp_hash_elt *)p)->var;
-
- return SSA_NAME_VERSION (var);
-}
-
-static int
-vrp_eq (const void *p1, const void *p2)
-{
- tree var1 = ((struct vrp_hash_elt *)p1)->var;
- tree var2 = ((struct vrp_hash_elt *)p2)->var;
-
- return var1 == var2;
-}
-
/* Hashing and equality functions for AVAIL_EXPRS. The table stores
MODIFY_EXPR statements. We compute a value number for expressions using
the code of the expression and the SSA numbers of its operands. */
static hashval_t
avail_expr_hash (const void *p)
{
- stmt_ann_t ann = ((struct expr_hash_elt *)p)->ann;
+ tree stmt = ((struct expr_hash_elt *)p)->stmt;
tree rhs = ((struct expr_hash_elt *)p)->rhs;
+ tree vuse;
+ ssa_op_iter iter;
hashval_t val = 0;
- size_t i;
- vuse_optype vuses;
/* iterative_hash_expr knows how to deal with any expression and
deals with commutative operators as well, so just use it instead
/* If the hash table entry is not associated with a statement, then we
can just hash the expression and not worry about virtual operands
and such. */
- if (!ann)
+ if (!stmt || !stmt_ann (stmt))
return val;
/* Add the SSA version numbers of every vuse operand. This is important
because compound variables like arrays are not renamed in the
operands. Rather, the rename is done on the virtual variable
representing all the elements of the array. */
- vuses = VUSE_OPS (ann);
- for (i = 0; i < NUM_VUSES (vuses); i++)
- val = iterative_hash_expr (VUSE_OP (vuses, i), val);
+ FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE)
+ val = iterative_hash_expr (vuse, val);
return val;
}
static int
avail_expr_eq (const void *p1, const void *p2)
{
- stmt_ann_t ann1 = ((struct expr_hash_elt *)p1)->ann;
+ tree stmt1 = ((struct expr_hash_elt *)p1)->stmt;
tree rhs1 = ((struct expr_hash_elt *)p1)->rhs;
- stmt_ann_t ann2 = ((struct expr_hash_elt *)p2)->ann;
+ tree stmt2 = ((struct expr_hash_elt *)p2)->stmt;
tree rhs2 = ((struct expr_hash_elt *)p2)->rhs;
/* If they are the same physical expression, return true. */
- if (rhs1 == rhs2 && ann1 == ann2)
+ if (rhs1 == rhs2 && stmt1 == stmt2)
return true;
/* If their codes are not equal, then quit now. */
|| lang_hooks.types_compatible_p (TREE_TYPE (rhs1), TREE_TYPE (rhs2)))
&& operand_equal_p (rhs1, rhs2, OEP_PURE_SAME))
{
- vuse_optype ops1 = NULL;
- vuse_optype ops2 = NULL;
- size_t num_ops1 = 0;
- size_t num_ops2 = 0;
- size_t i;
-
- if (ann1)
- {
- ops1 = VUSE_OPS (ann1);
- num_ops1 = NUM_VUSES (ops1);
- }
-
- if (ann2)
- {
- ops2 = VUSE_OPS (ann2);
- num_ops2 = NUM_VUSES (ops2);
- }
-
- /* If the number of virtual uses is different, then we consider
- them not equal. */
- if (num_ops1 != num_ops2)
- return false;
-
- for (i = 0; i < num_ops1; i++)
- if (VUSE_OP (ops1, i) != VUSE_OP (ops2, i))
- return false;
-
- gcc_assert (((struct expr_hash_elt *)p1)->hash
+ bool ret = compare_ssa_operands_equal (stmt1, stmt2, SSA_OP_VUSE);
+ gcc_assert (!ret || ((struct expr_hash_elt *)p1)->hash
== ((struct expr_hash_elt *)p2)->hash);
- return true;
+ return ret;
}
return false;
}
-
-/* Given STMT and a pointer to the block local definitions BLOCK_DEFS_P,
- register register all objects set by this statement into BLOCK_DEFS_P
- and CURRDEFS. */
-
-static void
-register_definitions_for_stmt (tree stmt)
-{
- tree def;
- ssa_op_iter iter;
-
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
- {
-
- /* FIXME: We shouldn't be registering new defs if the variable
- doesn't need to be renamed. */
- register_new_def (def, &block_defs_stack);
- }
-}
-
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