/* Full and partial redundancy elimination and code hoisting on SSA GIMPLE.
- Copyright (C) 2001-2017 Free Software Foundation, Inc.
+ Copyright (C) 2001-2018 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
<stevenb@suse.de>
#include "dbgcnt.h"
#include "domwalk.h"
#include "tree-ssa-propagate.h"
+#include "tree-ssa-dce.h"
#include "tree-cfgcleanup.h"
#include "alias.h"
return expressions[id];
}
-/* Free the expression id field in all of our expressions,
- and then destroy the expressions array. */
-
-static void
-clear_expression_ids (void)
-{
- expressions.release ();
-}
-
static object_allocator<pre_expr_d> pre_expr_pool ("pre_expr nodes");
/* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
gcc_unreachable ();
}
-/* Get a representative SSA_NAME for a given expression.
+/* Get a representative SSA_NAME for a given expression that is available in B.
Since all of our sub-expressions are treated as values, we require
them to be SSA_NAME's for simplicity.
Prior versions of GVNPRE used to use "value handles" here, so that
them to be usable without finding leaders). */
static tree
-get_representative_for (const pre_expr e)
+get_representative_for (const pre_expr e, basic_block b = NULL)
{
- tree name;
+ tree name, valnum = NULL_TREE;
unsigned int value_id = get_expr_value_id (e);
switch (e->kind)
{
pre_expr rep = expression_for_id (i);
if (rep->kind == NAME)
- return VN_INFO (PRE_EXPR_NAME (rep))->valnum;
+ {
+ tree name = PRE_EXPR_NAME (rep);
+ valnum = VN_INFO (name)->valnum;
+ gimple *def = SSA_NAME_DEF_STMT (name);
+ /* We have to return either a new representative or one
+ that can be used for expression simplification and thus
+ is available in B. */
+ if (! b
+ || gimple_nop_p (def)
+ || dominated_by_p (CDI_DOMINATORS, b, gimple_bb (def)))
+ return name;
+ }
else if (rep->kind == CONSTANT)
return PRE_EXPR_CONSTANT (rep);
}
to compute it. */
name = make_temp_ssa_name (get_expr_type (e), gimple_build_nop (), "pretmp");
VN_INFO_GET (name)->value_id = value_id;
- VN_INFO (name)->valnum = name;
+ VN_INFO (name)->valnum = valnum ? valnum : name;
/* ??? For now mark this SSA name for release by SCCVN. */
VN_INFO (name)->needs_insertion = true;
add_to_value (value_id, get_or_alloc_expr_for_name (name));
}
-
static pre_expr
phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
basic_block pred, basic_block phiblock);
leader = find_leader_in_sets (op_val_id, set1, set2);
result = phi_translate (leader, set1, set2, pred, phiblock);
if (result && result != leader)
- newnary->op[i] = get_representative_for (result);
+ /* Force a leader as well as we are simplifying this
+ expression. */
+ newnary->op[i] = get_representative_for (result, pred);
else if (!result)
return NULL;
return constant;
}
+ /* vn_nary_* do not valueize operands. */
+ for (i = 0; i < newnary->length; ++i)
+ if (TREE_CODE (newnary->op[i]) == SSA_NAME)
+ newnary->op[i] = VN_INFO (newnary->op[i])->valnum;
tree result = vn_nary_op_lookup_pieces (newnary->length,
newnary->opcode,
newnary->type,
PRE_EXPR_NARY (expr) = nary;
new_val_id = nary->value_id;
get_or_alloc_expression_id (expr);
- /* When we end up re-using a value number make sure that
- doesn't have unrelated (which we can't check here)
- range or points-to info on it. */
- if (result
- && INTEGRAL_TYPE_P (TREE_TYPE (result))
- && SSA_NAME_RANGE_INFO (result)
- && ! SSA_NAME_IS_DEFAULT_DEF (result))
- {
- if (! VN_INFO (result)->info.range_info)
- {
- VN_INFO (result)->info.range_info
- = SSA_NAME_RANGE_INFO (result);
- VN_INFO (result)->range_info_anti_range_p
- = SSA_NAME_ANTI_RANGE_P (result);
- }
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "clearing range info of ");
- print_generic_expr (dump_file, result);
- fprintf (dump_file, "\n");
- }
- SSA_NAME_RANGE_INFO (result) = NULL;
- }
- else if (result
- && POINTER_TYPE_P (TREE_TYPE (result))
- && SSA_NAME_PTR_INFO (result)
- && ! SSA_NAME_IS_DEFAULT_DEF (result))
- {
- if (! VN_INFO (result)->info.ptr_info)
- VN_INFO (result)->info.ptr_info
- = SSA_NAME_PTR_INFO (result);
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "clearing points-to info of ");
- print_generic_expr (dump_file, result);
- fprintf (dump_file, "\n");
- }
- SSA_NAME_PTR_INFO (result) = NULL;
- }
}
else
{
if (TREE_CODE (baseop) == ADDR_EXPR
&& handled_component_p (TREE_OPERAND (baseop, 0)))
{
- HOST_WIDE_INT off;
+ poly_int64 off;
tree base;
base = get_addr_base_and_unit_offset (TREE_OPERAND (baseop, 0),
&off);
that value numbering saw through. */
case NAME:
folded = PRE_EXPR_NAME (expr);
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (folded))
+ return NULL_TREE;
if (useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
return folded;
break;
gcc_assert (!(pred->flags & EDGE_ABNORMAL));
if (!gimple_seq_empty_p (stmts))
{
- gsi_insert_seq_on_edge (pred, stmts);
+ basic_block new_bb = gsi_insert_seq_on_edge_immediate (pred, stmts);
+ gcc_assert (! new_bb);
insertions = true;
}
if (!builtexpr)
free (worklist);
}
-/* Cheap DCE of a known set of possibly dead stmts.
-
- Because we don't follow exactly the standard PRE algorithm, and decide not
- to insert PHI nodes sometimes, and because value numbering of casts isn't
- perfect, we sometimes end up inserting dead code. This simple DCE-like
- pass removes any insertions we made that weren't actually used. */
-
-static void
-remove_dead_inserted_code (void)
-{
- /* ??? Re-use inserted_exprs as worklist not only as initial set.
- This may end up removing non-inserted code as well. If we
- keep inserted_exprs unchanged we could restrict new worklist
- elements to members of inserted_exprs. */
- bitmap worklist = inserted_exprs;
- while (! bitmap_empty_p (worklist))
- {
- /* Pop item. */
- unsigned i = bitmap_first_set_bit (worklist);
- bitmap_clear_bit (worklist, i);
-
- tree def = ssa_name (i);
- /* Removed by somebody else or still in use. */
- if (! def || ! has_zero_uses (def))
- continue;
-
- gimple *t = SSA_NAME_DEF_STMT (def);
- if (gimple_has_side_effects (t))
- continue;
-
- /* Add uses to the worklist. */
- ssa_op_iter iter;
- use_operand_p use_p;
- FOR_EACH_PHI_OR_STMT_USE (use_p, t, iter, SSA_OP_USE)
- {
- tree use = USE_FROM_PTR (use_p);
- if (TREE_CODE (use) == SSA_NAME
- && ! SSA_NAME_IS_DEFAULT_DEF (use))
- bitmap_set_bit (worklist, SSA_NAME_VERSION (use));
- }
-
- /* Remove stmt. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Removing unnecessary insertion:");
- print_gimple_stmt (dump_file, t, 0);
- }
- gimple_stmt_iterator gsi = gsi_for_stmt (t);
- if (gimple_code (t) == GIMPLE_PHI)
- remove_phi_node (&gsi, true);
- else
- {
- gsi_remove (&gsi, true);
- release_defs (t);
- }
- }
-}
-
/* Initialize data structures used by PRE. */
fini_pre ()
{
value_expressions.release ();
+ expressions.release ();
BITMAP_FREE (inserted_exprs);
bitmap_obstack_release (&grand_bitmap_obstack);
bitmap_set_pool.release ();
loop_optimizer_init may create new phis, etc. */
loop_optimizer_init (LOOPS_NORMAL);
split_critical_edges ();
+ scev_initialize ();
run_scc_vn (VN_WALK);
init_pre ();
- scev_initialize ();
-
- /* Collect and value number expressions computed in each basic block. */
- compute_avail ();
/* Insert can get quite slow on an incredibly large number of basic
blocks due to some quadratic behavior. Until this behavior is
fixed, don't run it when he have an incredibly large number of
bb's. If we aren't going to run insert, there is no point in
- computing ANTIC, either, even though it's plenty fast. */
+ computing ANTIC, either, even though it's plenty fast nor do
+ we require AVAIL. */
if (n_basic_blocks_for_fn (fun) < 4000)
{
+ compute_avail ();
compute_antic ();
insert ();
}
not keeping virtual operands up-to-date. */
gcc_assert (!need_ssa_update_p (fun));
- /* Remove all the redundant expressions. */
- todo |= vn_eliminate (inserted_exprs);
-
statistics_counter_event (fun, "Insertions", pre_stats.insertions);
statistics_counter_event (fun, "PA inserted", pre_stats.pa_insert);
statistics_counter_event (fun, "HOIST inserted", pre_stats.hoist_insert);
statistics_counter_event (fun, "New PHIs", pre_stats.phis);
- clear_expression_ids ();
+ /* Remove all the redundant expressions. */
+ todo |= vn_eliminate (inserted_exprs);
+
+ /* Because we don't follow exactly the standard PRE algorithm, and decide not
+ to insert PHI nodes sometimes, and because value numbering of casts isn't
+ perfect, we sometimes end up inserting dead code. This simple DCE-like
+ pass removes any insertions we made that weren't actually used. */
+ simple_dce_from_worklist (inserted_exprs);
- scev_finalize ();
- remove_dead_inserted_code ();
fini_pre ();
+
+ scev_finalize ();
loop_optimizer_finalize ();
/* Restore SSA info before tail-merging as that resets it as well. */
projects / gcc.git / blobdiff