#include "gimplify.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
-#include "tree-ssa-loop.h"
#include "tree-into-ssa.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
#include "dbgcnt.h"
#include "domwalk.h"
#include "tree-ssa-propagate.h"
-#include "ipa-utils.h"
#include "tree-cfgcleanup.h"
-#include "langhooks.h"
#include "alias.h"
/* Even though this file is called tree-ssa-pre.c, we actually
optimization PRE was able to perform. */
static struct
{
- /* The number of RHS computations eliminated by PRE. */
- int eliminations;
-
/* The number of new expressions/temporaries generated by PRE. */
int insertions;
free (worklist);
}
-class eliminate_dom_walker : public dom_walker
-{
-public:
- eliminate_dom_walker (cdi_direction direction, bool do_pre_);
- ~eliminate_dom_walker ();
-
- virtual edge before_dom_children (basic_block);
- virtual void after_dom_children (basic_block);
-
- tree eliminate_avail (tree op);
- void eliminate_push_avail (tree op);
- tree eliminate_insert (gimple_stmt_iterator *gsi, tree val);
-
- bool do_pre;
- unsigned int el_todo;
-
- /* Blocks with statements that have had their EH properties changed. */
- bitmap need_eh_cleanup;
-
- /* Blocks with statements that have had their AB properties changed. */
- bitmap need_ab_cleanup;
-
- auto_vec<gimple *> to_remove;
- auto_vec<gimple *> to_fixup;
- auto_vec<tree> avail;
- auto_vec<tree> avail_stack;
-};
-
-eliminate_dom_walker::eliminate_dom_walker (cdi_direction direction,
- bool do_pre_)
- : dom_walker (direction), do_pre (do_pre_), el_todo (0)
-{
- need_eh_cleanup = BITMAP_ALLOC (NULL);
- need_ab_cleanup = BITMAP_ALLOC (NULL);
-}
-
-eliminate_dom_walker::~eliminate_dom_walker ()
-{
- BITMAP_FREE (need_eh_cleanup);
- BITMAP_FREE (need_ab_cleanup);
-}
-
-/* Return a leader for OP that is available at the current point of the
- eliminate domwalk. */
-
-tree
-eliminate_dom_walker::eliminate_avail (tree op)
-{
- tree valnum = VN_INFO (op)->valnum;
- if (TREE_CODE (valnum) == SSA_NAME)
- {
- if (SSA_NAME_IS_DEFAULT_DEF (valnum))
- return valnum;
- if (avail.length () > SSA_NAME_VERSION (valnum))
- return avail[SSA_NAME_VERSION (valnum)];
- }
- else if (is_gimple_min_invariant (valnum))
- return valnum;
- return NULL_TREE;
-}
-
-/* At the current point of the eliminate domwalk make OP available. */
-
-void
-eliminate_dom_walker::eliminate_push_avail (tree op)
-{
- tree valnum = VN_INFO (op)->valnum;
- if (TREE_CODE (valnum) == SSA_NAME)
- {
- if (avail.length () <= SSA_NAME_VERSION (valnum))
- avail.safe_grow_cleared (SSA_NAME_VERSION (valnum) + 1);
- tree pushop = op;
- if (avail[SSA_NAME_VERSION (valnum)])
- pushop = avail[SSA_NAME_VERSION (valnum)];
- avail_stack.safe_push (pushop);
- avail[SSA_NAME_VERSION (valnum)] = op;
- }
-}
-
-/* Insert the expression recorded by SCCVN for VAL at *GSI. Returns
- the leader for the expression if insertion was successful. */
-
-tree
-eliminate_dom_walker::eliminate_insert (gimple_stmt_iterator *gsi, tree val)
-{
- /* We can insert a sequence with a single assignment only. */
- gimple_seq stmts = VN_INFO (val)->expr;
- if (!gimple_seq_singleton_p (stmts))
- return NULL_TREE;
- gassign *stmt = dyn_cast <gassign *> (gimple_seq_first_stmt (stmts));
- if (!stmt
- || (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt))
- && gimple_assign_rhs_code (stmt) != VIEW_CONVERT_EXPR
- && gimple_assign_rhs_code (stmt) != BIT_FIELD_REF
- && (gimple_assign_rhs_code (stmt) != BIT_AND_EXPR
- || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)))
- return NULL_TREE;
-
- tree op = gimple_assign_rhs1 (stmt);
- if (gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR
- || gimple_assign_rhs_code (stmt) == BIT_FIELD_REF)
- op = TREE_OPERAND (op, 0);
- tree leader = TREE_CODE (op) == SSA_NAME ? eliminate_avail (op) : op;
- if (!leader)
- return NULL_TREE;
-
- tree res;
- stmts = NULL;
- if (gimple_assign_rhs_code (stmt) == BIT_FIELD_REF)
- res = gimple_build (&stmts, BIT_FIELD_REF,
- TREE_TYPE (val), leader,
- TREE_OPERAND (gimple_assign_rhs1 (stmt), 1),
- TREE_OPERAND (gimple_assign_rhs1 (stmt), 2));
- else if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR)
- res = gimple_build (&stmts, BIT_AND_EXPR,
- TREE_TYPE (val), leader, gimple_assign_rhs2 (stmt));
- else
- res = gimple_build (&stmts, gimple_assign_rhs_code (stmt),
- TREE_TYPE (val), leader);
- if (TREE_CODE (res) != SSA_NAME
- || SSA_NAME_IS_DEFAULT_DEF (res)
- || gimple_bb (SSA_NAME_DEF_STMT (res)))
- {
- gimple_seq_discard (stmts);
-
- /* During propagation we have to treat SSA info conservatively
- and thus we can end up simplifying the inserted expression
- at elimination time to sth not defined in stmts. */
- /* But then this is a redundancy we failed to detect. Which means
- res now has two values. That doesn't play well with how
- we track availability here, so give up. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- if (TREE_CODE (res) == SSA_NAME)
- res = eliminate_avail (res);
- if (res)
- {
- fprintf (dump_file, "Failed to insert expression for value ");
- print_generic_expr (dump_file, val);
- fprintf (dump_file, " which is really fully redundant to ");
- print_generic_expr (dump_file, res);
- fprintf (dump_file, "\n");
- }
- }
-
- return NULL_TREE;
- }
- else
- {
- gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
- VN_INFO_GET (res)->valnum = val;
- }
-
- pre_stats.insertions++;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Inserted ");
- print_gimple_stmt (dump_file, SSA_NAME_DEF_STMT (res), 0);
- }
-
- return res;
-}
-
-
-
-/* Perform elimination for the basic-block B during the domwalk. */
-
-edge
-eliminate_dom_walker::before_dom_children (basic_block b)
-{
- /* Mark new bb. */
- avail_stack.safe_push (NULL_TREE);
-
- /* Skip unreachable blocks marked unreachable during the SCCVN domwalk. */
- edge_iterator ei;
- edge e;
- FOR_EACH_EDGE (e, ei, b->preds)
- if (e->flags & EDGE_EXECUTABLE)
- break;
- if (! e)
- return NULL;
-
- for (gphi_iterator gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
- {
- gphi *phi = gsi.phi ();
- tree res = PHI_RESULT (phi);
-
- if (virtual_operand_p (res))
- {
- gsi_next (&gsi);
- continue;
- }
-
- tree sprime = eliminate_avail (res);
- if (sprime
- && sprime != res)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Replaced redundant PHI node defining ");
- print_generic_expr (dump_file, res);
- fprintf (dump_file, " with ");
- print_generic_expr (dump_file, sprime);
- fprintf (dump_file, "\n");
- }
-
- /* If we inserted this PHI node ourself, it's not an elimination. */
- if (inserted_exprs
- && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res)))
- pre_stats.phis--;
- else
- pre_stats.eliminations++;
-
- /* If we will propagate into all uses don't bother to do
- anything. */
- if (may_propagate_copy (res, sprime))
- {
- /* Mark the PHI for removal. */
- to_remove.safe_push (phi);
- gsi_next (&gsi);
- continue;
- }
-
- remove_phi_node (&gsi, false);
-
- if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
- sprime = fold_convert (TREE_TYPE (res), sprime);
- gimple *stmt = gimple_build_assign (res, sprime);
- gimple_stmt_iterator gsi2 = gsi_after_labels (b);
- gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
- continue;
- }
-
- eliminate_push_avail (res);
- gsi_next (&gsi);
- }
-
- for (gimple_stmt_iterator gsi = gsi_start_bb (b);
- !gsi_end_p (gsi);
- gsi_next (&gsi))
- {
- tree sprime = NULL_TREE;
- gimple *stmt = gsi_stmt (gsi);
- tree lhs = gimple_get_lhs (stmt);
- if (lhs && TREE_CODE (lhs) == SSA_NAME
- && !gimple_has_volatile_ops (stmt)
- /* See PR43491. Do not replace a global register variable when
- it is a the RHS of an assignment. Do replace local register
- variables since gcc does not guarantee a local variable will
- be allocated in register.
- ??? The fix isn't effective here. This should instead
- be ensured by not value-numbering them the same but treating
- them like volatiles? */
- && !(gimple_assign_single_p (stmt)
- && (TREE_CODE (gimple_assign_rhs1 (stmt)) == VAR_DECL
- && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt))
- && is_global_var (gimple_assign_rhs1 (stmt)))))
- {
- sprime = eliminate_avail (lhs);
- if (!sprime)
- {
- /* If there is no existing usable leader but SCCVN thinks
- it has an expression it wants to use as replacement,
- insert that. */
- tree val = VN_INFO (lhs)->valnum;
- if (val != VN_TOP
- && TREE_CODE (val) == SSA_NAME
- && VN_INFO (val)->needs_insertion
- && VN_INFO (val)->expr != NULL
- && (sprime = eliminate_insert (&gsi, val)) != NULL_TREE)
- eliminate_push_avail (sprime);
- }
-
- /* If this now constitutes a copy duplicate points-to
- and range info appropriately. This is especially
- important for inserted code. See tree-ssa-copy.c
- for similar code. */
- if (sprime
- && TREE_CODE (sprime) == SSA_NAME)
- {
- basic_block sprime_b = gimple_bb (SSA_NAME_DEF_STMT (sprime));
- if (POINTER_TYPE_P (TREE_TYPE (lhs))
- && VN_INFO_PTR_INFO (lhs)
- && ! VN_INFO_PTR_INFO (sprime))
- {
- duplicate_ssa_name_ptr_info (sprime,
- VN_INFO_PTR_INFO (lhs));
- if (b != sprime_b)
- mark_ptr_info_alignment_unknown
- (SSA_NAME_PTR_INFO (sprime));
- }
- else if (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- && VN_INFO_RANGE_INFO (lhs)
- && ! VN_INFO_RANGE_INFO (sprime)
- && b == sprime_b)
- duplicate_ssa_name_range_info (sprime,
- VN_INFO_RANGE_TYPE (lhs),
- VN_INFO_RANGE_INFO (lhs));
- }
-
- /* Inhibit the use of an inserted PHI on a loop header when
- the address of the memory reference is a simple induction
- variable. In other cases the vectorizer won't do anything
- anyway (either it's loop invariant or a complicated
- expression). */
- if (sprime
- && TREE_CODE (sprime) == SSA_NAME
- && do_pre
- && (flag_tree_loop_vectorize || flag_tree_parallelize_loops > 1)
- && loop_outer (b->loop_father)
- && has_zero_uses (sprime)
- && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (sprime))
- && gimple_assign_load_p (stmt))
- {
- gimple *def_stmt = SSA_NAME_DEF_STMT (sprime);
- basic_block def_bb = gimple_bb (def_stmt);
- if (gimple_code (def_stmt) == GIMPLE_PHI
- && def_bb->loop_father->header == def_bb)
- {
- loop_p loop = def_bb->loop_father;
- ssa_op_iter iter;
- tree op;
- bool found = false;
- FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
- {
- affine_iv iv;
- def_bb = gimple_bb (SSA_NAME_DEF_STMT (op));
- if (def_bb
- && flow_bb_inside_loop_p (loop, def_bb)
- && simple_iv (loop, loop, op, &iv, true))
- {
- found = true;
- break;
- }
- }
- if (found)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Not replacing ");
- print_gimple_expr (dump_file, stmt, 0);
- fprintf (dump_file, " with ");
- print_generic_expr (dump_file, sprime);
- fprintf (dump_file, " which would add a loop"
- " carried dependence to loop %d\n",
- loop->num);
- }
- /* Don't keep sprime available. */
- sprime = NULL_TREE;
- }
- }
- }
-
- if (sprime)
- {
- /* If we can propagate the value computed for LHS into
- all uses don't bother doing anything with this stmt. */
- if (may_propagate_copy (lhs, sprime))
- {
- /* Mark it for removal. */
- to_remove.safe_push (stmt);
-
- /* ??? Don't count copy/constant propagations. */
- if (gimple_assign_single_p (stmt)
- && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
- || gimple_assign_rhs1 (stmt) == sprime))
- continue;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Replaced ");
- print_gimple_expr (dump_file, stmt, 0);
- fprintf (dump_file, " with ");
- print_generic_expr (dump_file, sprime);
- fprintf (dump_file, " in all uses of ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
-
- pre_stats.eliminations++;
- continue;
- }
-
- /* If this is an assignment from our leader (which
- happens in the case the value-number is a constant)
- then there is nothing to do. */
- if (gimple_assign_single_p (stmt)
- && sprime == gimple_assign_rhs1 (stmt))
- continue;
-
- /* Else replace its RHS. */
- bool can_make_abnormal_goto
- = is_gimple_call (stmt)
- && stmt_can_make_abnormal_goto (stmt);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Replaced ");
- print_gimple_expr (dump_file, stmt, 0);
- fprintf (dump_file, " with ");
- print_generic_expr (dump_file, sprime);
- fprintf (dump_file, " in ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
-
- pre_stats.eliminations++;
- gimple *orig_stmt = stmt;
- if (!useless_type_conversion_p (TREE_TYPE (lhs),
- TREE_TYPE (sprime)))
- sprime = fold_convert (TREE_TYPE (lhs), sprime);
- tree vdef = gimple_vdef (stmt);
- tree vuse = gimple_vuse (stmt);
- propagate_tree_value_into_stmt (&gsi, sprime);
- stmt = gsi_stmt (gsi);
- update_stmt (stmt);
- if (vdef != gimple_vdef (stmt))
- VN_INFO (vdef)->valnum = vuse;
-
- /* If we removed EH side-effects from the statement, clean
- its EH information. */
- if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
- {
- bitmap_set_bit (need_eh_cleanup,
- gimple_bb (stmt)->index);
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Removed EH side-effects.\n");
- }
-
- /* Likewise for AB side-effects. */
- if (can_make_abnormal_goto
- && !stmt_can_make_abnormal_goto (stmt))
- {
- bitmap_set_bit (need_ab_cleanup,
- gimple_bb (stmt)->index);
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Removed AB side-effects.\n");
- }
-
- continue;
- }
- }
-
- /* If the statement is a scalar store, see if the expression
- has the same value number as its rhs. If so, the store is
- dead. */
- if (gimple_assign_single_p (stmt)
- && !gimple_has_volatile_ops (stmt)
- && !is_gimple_reg (gimple_assign_lhs (stmt))
- && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
- || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
- {
- tree val;
- tree rhs = gimple_assign_rhs1 (stmt);
- vn_reference_t vnresult;
- val = vn_reference_lookup (lhs, gimple_vuse (stmt), VN_WALKREWRITE,
- &vnresult, false);
- if (TREE_CODE (rhs) == SSA_NAME)
- rhs = VN_INFO (rhs)->valnum;
- if (val
- && operand_equal_p (val, rhs, 0))
- {
- /* We can only remove the later store if the former aliases
- at least all accesses the later one does or if the store
- was to readonly memory storing the same value. */
- alias_set_type set = get_alias_set (lhs);
- if (! vnresult
- || vnresult->set == set
- || alias_set_subset_of (set, vnresult->set))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Deleted redundant store ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
-
- /* Queue stmt for removal. */
- to_remove.safe_push (stmt);
- continue;
- }
- }
- }
-
- /* If this is a control statement value numbering left edges
- unexecuted on force the condition in a way consistent with
- that. */
- if (gcond *cond = dyn_cast <gcond *> (stmt))
- {
- if ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE)
- ^ (EDGE_SUCC (b, 1)->flags & EDGE_EXECUTABLE))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Removing unexecutable edge from ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
- if (((EDGE_SUCC (b, 0)->flags & EDGE_TRUE_VALUE) != 0)
- == ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE) != 0))
- gimple_cond_make_true (cond);
- else
- gimple_cond_make_false (cond);
- update_stmt (cond);
- el_todo |= TODO_cleanup_cfg;
- continue;
- }
- }
-
- bool can_make_abnormal_goto = stmt_can_make_abnormal_goto (stmt);
- bool was_noreturn = (is_gimple_call (stmt)
- && gimple_call_noreturn_p (stmt));
- tree vdef = gimple_vdef (stmt);
- tree vuse = gimple_vuse (stmt);
-
- /* If we didn't replace the whole stmt (or propagate the result
- into all uses), replace all uses on this stmt with their
- leaders. */
- bool modified = false;
- use_operand_p use_p;
- ssa_op_iter iter;
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
- {
- tree use = USE_FROM_PTR (use_p);
- /* ??? The call code above leaves stmt operands un-updated. */
- if (TREE_CODE (use) != SSA_NAME)
- continue;
- tree sprime = eliminate_avail (use);
- if (sprime && sprime != use
- && may_propagate_copy (use, sprime)
- /* We substitute into debug stmts to avoid excessive
- debug temporaries created by removed stmts, but we need
- to avoid doing so for inserted sprimes as we never want
- to create debug temporaries for them. */
- && (!inserted_exprs
- || TREE_CODE (sprime) != SSA_NAME
- || !is_gimple_debug (stmt)
- || !bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (sprime))))
- {
- propagate_value (use_p, sprime);
- modified = true;
- }
- }
-
- /* Fold the stmt if modified, this canonicalizes MEM_REFs we propagated
- into which is a requirement for the IPA devirt machinery. */
- gimple *old_stmt = stmt;
- if (modified)
- {
- /* If a formerly non-invariant ADDR_EXPR is turned into an
- invariant one it was on a separate stmt. */
- if (gimple_assign_single_p (stmt)
- && TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR)
- recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
- gimple_stmt_iterator prev = gsi;
- gsi_prev (&prev);
- if (fold_stmt (&gsi))
- {
- /* fold_stmt may have created new stmts inbetween
- the previous stmt and the folded stmt. Mark
- all defs created there as varying to not confuse
- the SCCVN machinery as we're using that even during
- elimination. */
- if (gsi_end_p (prev))
- prev = gsi_start_bb (b);
- else
- gsi_next (&prev);
- if (gsi_stmt (prev) != gsi_stmt (gsi))
- do
- {
- tree def;
- ssa_op_iter dit;
- FOR_EACH_SSA_TREE_OPERAND (def, gsi_stmt (prev),
- dit, SSA_OP_ALL_DEFS)
- /* As existing DEFs may move between stmts
- we have to guard VN_INFO_GET. */
- if (! has_VN_INFO (def))
- VN_INFO_GET (def)->valnum = def;
- if (gsi_stmt (prev) == gsi_stmt (gsi))
- break;
- gsi_next (&prev);
- }
- while (1);
- }
- stmt = gsi_stmt (gsi);
- /* In case we folded the stmt away schedule the NOP for removal. */
- if (gimple_nop_p (stmt))
- to_remove.safe_push (stmt);
- }
-
- /* Visit indirect calls and turn them into direct calls if
- possible using the devirtualization machinery. Do this before
- checking for required EH/abnormal/noreturn cleanup as devird
- may expose more of those. */
- if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
- {
- tree fn = gimple_call_fn (call_stmt);
- if (fn
- && flag_devirtualize
- && virtual_method_call_p (fn))
- {
- tree otr_type = obj_type_ref_class (fn);
- unsigned HOST_WIDE_INT otr_tok
- = tree_to_uhwi (OBJ_TYPE_REF_TOKEN (fn));
- tree instance;
- ipa_polymorphic_call_context context (current_function_decl,
- fn, stmt, &instance);
- context.get_dynamic_type (instance, OBJ_TYPE_REF_OBJECT (fn),
- otr_type, stmt);
- bool final;
- vec <cgraph_node *> targets
- = possible_polymorphic_call_targets (obj_type_ref_class (fn),
- otr_tok, context, &final);
- if (dump_file)
- dump_possible_polymorphic_call_targets (dump_file,
- obj_type_ref_class (fn),
- otr_tok, context);
- if (final && targets.length () <= 1 && dbg_cnt (devirt))
- {
- tree fn;
- if (targets.length () == 1)
- fn = targets[0]->decl;
- else
- fn = builtin_decl_implicit (BUILT_IN_UNREACHABLE);
- if (dump_enabled_p ())
- {
- location_t loc = gimple_location (stmt);
- dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc,
- "converting indirect call to "
- "function %s\n",
- lang_hooks.decl_printable_name (fn, 2));
- }
- gimple_call_set_fndecl (call_stmt, fn);
- /* If changing the call to __builtin_unreachable
- or similar noreturn function, adjust gimple_call_fntype
- too. */
- if (gimple_call_noreturn_p (call_stmt)
- && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fn)))
- && TYPE_ARG_TYPES (TREE_TYPE (fn))
- && (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fn)))
- == void_type_node))
- gimple_call_set_fntype (call_stmt, TREE_TYPE (fn));
- maybe_remove_unused_call_args (cfun, call_stmt);
- modified = true;
- }
- }
- }
-
- if (modified)
- {
- /* When changing a call into a noreturn call, cfg cleanup
- is needed to fix up the noreturn call. */
- if (!was_noreturn
- && is_gimple_call (stmt) && gimple_call_noreturn_p (stmt))
- to_fixup.safe_push (stmt);
- /* When changing a condition or switch into one we know what
- edge will be executed, schedule a cfg cleanup. */
- if ((gimple_code (stmt) == GIMPLE_COND
- && (gimple_cond_true_p (as_a <gcond *> (stmt))
- || gimple_cond_false_p (as_a <gcond *> (stmt))))
- || (gimple_code (stmt) == GIMPLE_SWITCH
- && TREE_CODE (gimple_switch_index
- (as_a <gswitch *> (stmt))) == INTEGER_CST))
- el_todo |= TODO_cleanup_cfg;
- /* If we removed EH side-effects from the statement, clean
- its EH information. */
- if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
- {
- bitmap_set_bit (need_eh_cleanup,
- gimple_bb (stmt)->index);
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Removed EH side-effects.\n");
- }
- /* Likewise for AB side-effects. */
- if (can_make_abnormal_goto
- && !stmt_can_make_abnormal_goto (stmt))
- {
- bitmap_set_bit (need_ab_cleanup,
- gimple_bb (stmt)->index);
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Removed AB side-effects.\n");
- }
- update_stmt (stmt);
- if (vdef != gimple_vdef (stmt))
- VN_INFO (vdef)->valnum = vuse;
- }
-
- /* Make new values available - for fully redundant LHS we
- continue with the next stmt above and skip this. */
- def_operand_p defp;
- FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
- eliminate_push_avail (DEF_FROM_PTR (defp));
- }
-
- /* Replace destination PHI arguments. */
- FOR_EACH_EDGE (e, ei, b->succs)
- if (e->flags & EDGE_EXECUTABLE)
- for (gphi_iterator gsi = gsi_start_phis (e->dest);
- !gsi_end_p (gsi);
- gsi_next (&gsi))
- {
- gphi *phi = gsi.phi ();
- use_operand_p use_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e);
- tree arg = USE_FROM_PTR (use_p);
- if (TREE_CODE (arg) != SSA_NAME
- || virtual_operand_p (arg))
- continue;
- tree sprime = eliminate_avail (arg);
- if (sprime && may_propagate_copy (arg, sprime))
- propagate_value (use_p, sprime);
- }
- return NULL;
-}
-
-/* Make no longer available leaders no longer available. */
-
-void
-eliminate_dom_walker::after_dom_children (basic_block)
-{
- tree entry;
- while ((entry = avail_stack.pop ()) != NULL_TREE)
- {
- tree valnum = VN_INFO (entry)->valnum;
- tree old = avail[SSA_NAME_VERSION (valnum)];
- if (old == entry)
- avail[SSA_NAME_VERSION (valnum)] = NULL_TREE;
- else
- avail[SSA_NAME_VERSION (valnum)] = entry;
- }
-}
-
-/* Eliminate fully redundant computations. */
-
-static unsigned int
-eliminate (bool do_pre)
-{
- eliminate_dom_walker el (CDI_DOMINATORS, do_pre);
- el.avail.reserve (num_ssa_names);
-
- el.walk (cfun->cfg->x_entry_block_ptr);
-
- /* We cannot remove stmts during BB walk, especially not release SSA
- names there as this confuses the VN machinery. The stmts ending
- up in to_remove are either stores or simple copies.
- Remove stmts in reverse order to make debug stmt creation possible. */
- while (!el.to_remove.is_empty ())
- {
- gimple *stmt = el.to_remove.pop ();
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Removing dead stmt ");
- print_gimple_stmt (dump_file, stmt, 0, 0);
- }
-
- gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
- if (gimple_code (stmt) == GIMPLE_PHI)
- remove_phi_node (&gsi, true);
- else
- {
- basic_block bb = gimple_bb (stmt);
- unlink_stmt_vdef (stmt);
- if (gsi_remove (&gsi, true))
- bitmap_set_bit (el.need_eh_cleanup, bb->index);
- if (is_gimple_call (stmt) && stmt_can_make_abnormal_goto (stmt))
- bitmap_set_bit (el.need_ab_cleanup, bb->index);
- release_defs (stmt);
- }
-
- /* Removing a stmt may expose a forwarder block. */
- el.el_todo |= TODO_cleanup_cfg;
- }
-
- /* Fixup stmts that became noreturn calls. This may require splitting
- blocks and thus isn't possible during the dominator walk. Do this
- in reverse order so we don't inadvertedly remove a stmt we want to
- fixup by visiting a dominating now noreturn call first. */
- while (!el.to_fixup.is_empty ())
- {
- gimple *stmt = el.to_fixup.pop ();
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Fixing up noreturn call ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
-
- if (fixup_noreturn_call (stmt))
- el.el_todo |= TODO_cleanup_cfg;
- }
-
- bool do_eh_cleanup = !bitmap_empty_p (el.need_eh_cleanup);
- bool do_ab_cleanup = !bitmap_empty_p (el.need_ab_cleanup);
-
- if (do_eh_cleanup)
- gimple_purge_all_dead_eh_edges (el.need_eh_cleanup);
-
- if (do_ab_cleanup)
- gimple_purge_all_dead_abnormal_call_edges (el.need_ab_cleanup);
-
- if (do_eh_cleanup || do_ab_cleanup)
- el.el_todo |= TODO_cleanup_cfg;
- return el.el_todo;
-}
-
/* Cheap DCE of a known set of possibly dead stmts.
Because we don't follow exactly the standard PRE algorithm, and decide not
gcc_assert (!need_ssa_update_p (fun));
/* Remove all the redundant expressions. */
- todo |= eliminate (true);
+ 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);
- statistics_counter_event (fun, "Eliminated", pre_stats.eliminations);
clear_expression_ids ();
{
return new pass_pre (ctxt);
}
-
-namespace {
-
-const pass_data pass_data_fre =
-{
- GIMPLE_PASS, /* type */
- "fre", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- TV_TREE_FRE, /* tv_id */
- ( PROP_cfg | PROP_ssa ), /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_fre : public gimple_opt_pass
-{
-public:
- pass_fre (gcc::context *ctxt)
- : gimple_opt_pass (pass_data_fre, ctxt)
- {}
-
- /* opt_pass methods: */
- opt_pass * clone () { return new pass_fre (m_ctxt); }
- virtual bool gate (function *) { return flag_tree_fre != 0; }
- virtual unsigned int execute (function *);
-
-}; // class pass_fre
-
-unsigned int
-pass_fre::execute (function *fun)
-{
- unsigned int todo = 0;
-
- run_scc_vn (VN_WALKREWRITE);
-
- memset (&pre_stats, 0, sizeof (pre_stats));
-
- /* Remove all the redundant expressions. */
- todo |= eliminate (false);
-
- scc_vn_restore_ssa_info ();
- free_scc_vn ();
-
- statistics_counter_event (fun, "Insertions", pre_stats.insertions);
- statistics_counter_event (fun, "Eliminated", pre_stats.eliminations);
-
- return todo;
-}
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_fre (gcc::context *ctxt)
-{
- return new pass_fre (ctxt);
-}
#include "cfgloop.h"
#include "params.h"
#include "tree-ssa-propagate.h"
-#include "tree-ssa-sccvn.h"
#include "tree-cfg.h"
#include "domwalk.h"
#include "gimple-iterator.h"
#include "gimple-match.h"
#include "stringpool.h"
#include "attribs.h"
+#include "tree-pass.h"
+#include "statistics.h"
+#include "langhooks.h"
+#include "ipa-utils.h"
+#include "dbgcnt.h"
+#include "tree-cfgcleanup.h"
+#include "tree-ssa-loop.h"
+#include "tree-scalar-evolution.h"
+#include "tree-ssa-sccvn.h"
/* This algorithm is based on the SCC algorithm presented by Keith
Cooper and L. Taylor Simpson in "SCC-Based Value numbering"
return false;
}
+
+
+class eliminate_dom_walker : public dom_walker
+{
+public:
+ eliminate_dom_walker (cdi_direction, bitmap);
+ ~eliminate_dom_walker ();
+
+ virtual edge before_dom_children (basic_block);
+ virtual void after_dom_children (basic_block);
+
+ tree eliminate_avail (tree op);
+ void eliminate_push_avail (tree op);
+ tree eliminate_insert (gimple_stmt_iterator *gsi, tree val);
+
+ bool do_pre;
+ unsigned int el_todo;
+ unsigned int eliminations;
+ unsigned int insertions;
+
+ /* SSA names that had their defs inserted by PRE if do_pre. */
+ bitmap inserted_exprs;
+
+ /* Blocks with statements that have had their EH properties changed. */
+ bitmap need_eh_cleanup;
+
+ /* Blocks with statements that have had their AB properties changed. */
+ bitmap need_ab_cleanup;
+
+ auto_vec<gimple *> to_remove;
+ auto_vec<gimple *> to_fixup;
+ auto_vec<tree> avail;
+ auto_vec<tree> avail_stack;
+};
+
+eliminate_dom_walker::eliminate_dom_walker (cdi_direction direction,
+ bitmap inserted_exprs_)
+ : dom_walker (direction), do_pre (inserted_exprs_ != NULL),
+ el_todo (0), eliminations (0), insertions (0),
+ inserted_exprs (inserted_exprs_)
+{
+ need_eh_cleanup = BITMAP_ALLOC (NULL);
+ need_ab_cleanup = BITMAP_ALLOC (NULL);
+}
+
+eliminate_dom_walker::~eliminate_dom_walker ()
+{
+ BITMAP_FREE (need_eh_cleanup);
+ BITMAP_FREE (need_ab_cleanup);
+}
+
+/* Return a leader for OP that is available at the current point of the
+ eliminate domwalk. */
+
+tree
+eliminate_dom_walker::eliminate_avail (tree op)
+{
+ tree valnum = VN_INFO (op)->valnum;
+ if (TREE_CODE (valnum) == SSA_NAME)
+ {
+ if (SSA_NAME_IS_DEFAULT_DEF (valnum))
+ return valnum;
+ if (avail.length () > SSA_NAME_VERSION (valnum))
+ return avail[SSA_NAME_VERSION (valnum)];
+ }
+ else if (is_gimple_min_invariant (valnum))
+ return valnum;
+ return NULL_TREE;
+}
+
+/* At the current point of the eliminate domwalk make OP available. */
+
+void
+eliminate_dom_walker::eliminate_push_avail (tree op)
+{
+ tree valnum = VN_INFO (op)->valnum;
+ if (TREE_CODE (valnum) == SSA_NAME)
+ {
+ if (avail.length () <= SSA_NAME_VERSION (valnum))
+ avail.safe_grow_cleared (SSA_NAME_VERSION (valnum) + 1);
+ tree pushop = op;
+ if (avail[SSA_NAME_VERSION (valnum)])
+ pushop = avail[SSA_NAME_VERSION (valnum)];
+ avail_stack.safe_push (pushop);
+ avail[SSA_NAME_VERSION (valnum)] = op;
+ }
+}
+
+/* Insert the expression recorded by SCCVN for VAL at *GSI. Returns
+ the leader for the expression if insertion was successful. */
+
+tree
+eliminate_dom_walker::eliminate_insert (gimple_stmt_iterator *gsi, tree val)
+{
+ /* We can insert a sequence with a single assignment only. */
+ gimple_seq stmts = VN_INFO (val)->expr;
+ if (!gimple_seq_singleton_p (stmts))
+ return NULL_TREE;
+ gassign *stmt = dyn_cast <gassign *> (gimple_seq_first_stmt (stmts));
+ if (!stmt
+ || (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt))
+ && gimple_assign_rhs_code (stmt) != VIEW_CONVERT_EXPR
+ && gimple_assign_rhs_code (stmt) != BIT_FIELD_REF
+ && (gimple_assign_rhs_code (stmt) != BIT_AND_EXPR
+ || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST)))
+ return NULL_TREE;
+
+ tree op = gimple_assign_rhs1 (stmt);
+ if (gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR
+ || gimple_assign_rhs_code (stmt) == BIT_FIELD_REF)
+ op = TREE_OPERAND (op, 0);
+ tree leader = TREE_CODE (op) == SSA_NAME ? eliminate_avail (op) : op;
+ if (!leader)
+ return NULL_TREE;
+
+ tree res;
+ stmts = NULL;
+ if (gimple_assign_rhs_code (stmt) == BIT_FIELD_REF)
+ res = gimple_build (&stmts, BIT_FIELD_REF,
+ TREE_TYPE (val), leader,
+ TREE_OPERAND (gimple_assign_rhs1 (stmt), 1),
+ TREE_OPERAND (gimple_assign_rhs1 (stmt), 2));
+ else if (gimple_assign_rhs_code (stmt) == BIT_AND_EXPR)
+ res = gimple_build (&stmts, BIT_AND_EXPR,
+ TREE_TYPE (val), leader, gimple_assign_rhs2 (stmt));
+ else
+ res = gimple_build (&stmts, gimple_assign_rhs_code (stmt),
+ TREE_TYPE (val), leader);
+ if (TREE_CODE (res) != SSA_NAME
+ || SSA_NAME_IS_DEFAULT_DEF (res)
+ || gimple_bb (SSA_NAME_DEF_STMT (res)))
+ {
+ gimple_seq_discard (stmts);
+
+ /* During propagation we have to treat SSA info conservatively
+ and thus we can end up simplifying the inserted expression
+ at elimination time to sth not defined in stmts. */
+ /* But then this is a redundancy we failed to detect. Which means
+ res now has two values. That doesn't play well with how
+ we track availability here, so give up. */
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ if (TREE_CODE (res) == SSA_NAME)
+ res = eliminate_avail (res);
+ if (res)
+ {
+ fprintf (dump_file, "Failed to insert expression for value ");
+ print_generic_expr (dump_file, val);
+ fprintf (dump_file, " which is really fully redundant to ");
+ print_generic_expr (dump_file, res);
+ fprintf (dump_file, "\n");
+ }
+ }
+
+ return NULL_TREE;
+ }
+ else
+ {
+ gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+ VN_INFO_GET (res)->valnum = val;
+ }
+
+ insertions++;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Inserted ");
+ print_gimple_stmt (dump_file, SSA_NAME_DEF_STMT (res), 0);
+ }
+
+ return res;
+}
+
+
+
+/* Perform elimination for the basic-block B during the domwalk. */
+
+edge
+eliminate_dom_walker::before_dom_children (basic_block b)
+{
+ /* Mark new bb. */
+ avail_stack.safe_push (NULL_TREE);
+
+ /* Skip unreachable blocks marked unreachable during the SCCVN domwalk. */
+ edge_iterator ei;
+ edge e;
+ FOR_EACH_EDGE (e, ei, b->preds)
+ if (e->flags & EDGE_EXECUTABLE)
+ break;
+ if (! e)
+ return NULL;
+
+ for (gphi_iterator gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
+ {
+ gphi *phi = gsi.phi ();
+ tree res = PHI_RESULT (phi);
+
+ if (virtual_operand_p (res))
+ {
+ gsi_next (&gsi);
+ continue;
+ }
+
+ tree sprime = eliminate_avail (res);
+ if (sprime
+ && sprime != res)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Replaced redundant PHI node defining ");
+ print_generic_expr (dump_file, res);
+ fprintf (dump_file, " with ");
+ print_generic_expr (dump_file, sprime);
+ fprintf (dump_file, "\n");
+ }
+
+ /* If we inserted this PHI node ourself, it's not an elimination. */
+ if (! inserted_exprs
+ || ! bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res)))
+ eliminations++;
+
+ /* If we will propagate into all uses don't bother to do
+ anything. */
+ if (may_propagate_copy (res, sprime))
+ {
+ /* Mark the PHI for removal. */
+ to_remove.safe_push (phi);
+ gsi_next (&gsi);
+ continue;
+ }
+
+ remove_phi_node (&gsi, false);
+
+ if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
+ sprime = fold_convert (TREE_TYPE (res), sprime);
+ gimple *stmt = gimple_build_assign (res, sprime);
+ gimple_stmt_iterator gsi2 = gsi_after_labels (b);
+ gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
+ continue;
+ }
+
+ eliminate_push_avail (res);
+ gsi_next (&gsi);
+ }
+
+ for (gimple_stmt_iterator gsi = gsi_start_bb (b);
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ {
+ tree sprime = NULL_TREE;
+ gimple *stmt = gsi_stmt (gsi);
+ tree lhs = gimple_get_lhs (stmt);
+ if (lhs && TREE_CODE (lhs) == SSA_NAME
+ && !gimple_has_volatile_ops (stmt)
+ /* See PR43491. Do not replace a global register variable when
+ it is a the RHS of an assignment. Do replace local register
+ variables since gcc does not guarantee a local variable will
+ be allocated in register.
+ ??? The fix isn't effective here. This should instead
+ be ensured by not value-numbering them the same but treating
+ them like volatiles? */
+ && !(gimple_assign_single_p (stmt)
+ && (TREE_CODE (gimple_assign_rhs1 (stmt)) == VAR_DECL
+ && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt))
+ && is_global_var (gimple_assign_rhs1 (stmt)))))
+ {
+ sprime = eliminate_avail (lhs);
+ if (!sprime)
+ {
+ /* If there is no existing usable leader but SCCVN thinks
+ it has an expression it wants to use as replacement,
+ insert that. */
+ tree val = VN_INFO (lhs)->valnum;
+ if (val != VN_TOP
+ && TREE_CODE (val) == SSA_NAME
+ && VN_INFO (val)->needs_insertion
+ && VN_INFO (val)->expr != NULL
+ && (sprime = eliminate_insert (&gsi, val)) != NULL_TREE)
+ eliminate_push_avail (sprime);
+ }
+
+ /* If this now constitutes a copy duplicate points-to
+ and range info appropriately. This is especially
+ important for inserted code. See tree-ssa-copy.c
+ for similar code. */
+ if (sprime
+ && TREE_CODE (sprime) == SSA_NAME)
+ {
+ basic_block sprime_b = gimple_bb (SSA_NAME_DEF_STMT (sprime));
+ if (POINTER_TYPE_P (TREE_TYPE (lhs))
+ && VN_INFO_PTR_INFO (lhs)
+ && ! VN_INFO_PTR_INFO (sprime))
+ {
+ duplicate_ssa_name_ptr_info (sprime,
+ VN_INFO_PTR_INFO (lhs));
+ if (b != sprime_b)
+ mark_ptr_info_alignment_unknown
+ (SSA_NAME_PTR_INFO (sprime));
+ }
+ else if (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ && VN_INFO_RANGE_INFO (lhs)
+ && ! VN_INFO_RANGE_INFO (sprime)
+ && b == sprime_b)
+ duplicate_ssa_name_range_info (sprime,
+ VN_INFO_RANGE_TYPE (lhs),
+ VN_INFO_RANGE_INFO (lhs));
+ }
+
+ /* Inhibit the use of an inserted PHI on a loop header when
+ the address of the memory reference is a simple induction
+ variable. In other cases the vectorizer won't do anything
+ anyway (either it's loop invariant or a complicated
+ expression). */
+ if (sprime
+ && TREE_CODE (sprime) == SSA_NAME
+ && do_pre
+ && (flag_tree_loop_vectorize || flag_tree_parallelize_loops > 1)
+ && loop_outer (b->loop_father)
+ && has_zero_uses (sprime)
+ && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (sprime))
+ && gimple_assign_load_p (stmt))
+ {
+ gimple *def_stmt = SSA_NAME_DEF_STMT (sprime);
+ basic_block def_bb = gimple_bb (def_stmt);
+ if (gimple_code (def_stmt) == GIMPLE_PHI
+ && def_bb->loop_father->header == def_bb)
+ {
+ loop_p loop = def_bb->loop_father;
+ ssa_op_iter iter;
+ tree op;
+ bool found = false;
+ FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
+ {
+ affine_iv iv;
+ def_bb = gimple_bb (SSA_NAME_DEF_STMT (op));
+ if (def_bb
+ && flow_bb_inside_loop_p (loop, def_bb)
+ && simple_iv (loop, loop, op, &iv, true))
+ {
+ found = true;
+ break;
+ }
+ }
+ if (found)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Not replacing ");
+ print_gimple_expr (dump_file, stmt, 0);
+ fprintf (dump_file, " with ");
+ print_generic_expr (dump_file, sprime);
+ fprintf (dump_file, " which would add a loop"
+ " carried dependence to loop %d\n",
+ loop->num);
+ }
+ /* Don't keep sprime available. */
+ sprime = NULL_TREE;
+ }
+ }
+ }
+
+ if (sprime)
+ {
+ /* If we can propagate the value computed for LHS into
+ all uses don't bother doing anything with this stmt. */
+ if (may_propagate_copy (lhs, sprime))
+ {
+ /* Mark it for removal. */
+ to_remove.safe_push (stmt);
+
+ /* ??? Don't count copy/constant propagations. */
+ if (gimple_assign_single_p (stmt)
+ && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
+ || gimple_assign_rhs1 (stmt) == sprime))
+ continue;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Replaced ");
+ print_gimple_expr (dump_file, stmt, 0);
+ fprintf (dump_file, " with ");
+ print_generic_expr (dump_file, sprime);
+ fprintf (dump_file, " in all uses of ");
+ print_gimple_stmt (dump_file, stmt, 0);
+ }
+
+ eliminations++;
+ continue;
+ }
+
+ /* If this is an assignment from our leader (which
+ happens in the case the value-number is a constant)
+ then there is nothing to do. */
+ if (gimple_assign_single_p (stmt)
+ && sprime == gimple_assign_rhs1 (stmt))
+ continue;
+
+ /* Else replace its RHS. */
+ bool can_make_abnormal_goto
+ = is_gimple_call (stmt)
+ && stmt_can_make_abnormal_goto (stmt);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Replaced ");
+ print_gimple_expr (dump_file, stmt, 0);
+ fprintf (dump_file, " with ");
+ print_generic_expr (dump_file, sprime);
+ fprintf (dump_file, " in ");
+ print_gimple_stmt (dump_file, stmt, 0);
+ }
+
+ eliminations++;
+ gimple *orig_stmt = stmt;
+ if (!useless_type_conversion_p (TREE_TYPE (lhs),
+ TREE_TYPE (sprime)))
+ sprime = fold_convert (TREE_TYPE (lhs), sprime);
+ tree vdef = gimple_vdef (stmt);
+ tree vuse = gimple_vuse (stmt);
+ propagate_tree_value_into_stmt (&gsi, sprime);
+ stmt = gsi_stmt (gsi);
+ update_stmt (stmt);
+ if (vdef != gimple_vdef (stmt))
+ VN_INFO (vdef)->valnum = vuse;
+
+ /* If we removed EH side-effects from the statement, clean
+ its EH information. */
+ if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
+ {
+ bitmap_set_bit (need_eh_cleanup,
+ gimple_bb (stmt)->index);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " Removed EH side-effects.\n");
+ }
+
+ /* Likewise for AB side-effects. */
+ if (can_make_abnormal_goto
+ && !stmt_can_make_abnormal_goto (stmt))
+ {
+ bitmap_set_bit (need_ab_cleanup,
+ gimple_bb (stmt)->index);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " Removed AB side-effects.\n");
+ }
+
+ continue;
+ }
+ }
+
+ /* If the statement is a scalar store, see if the expression
+ has the same value number as its rhs. If so, the store is
+ dead. */
+ if (gimple_assign_single_p (stmt)
+ && !gimple_has_volatile_ops (stmt)
+ && !is_gimple_reg (gimple_assign_lhs (stmt))
+ && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
+ || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
+ {
+ tree val;
+ tree rhs = gimple_assign_rhs1 (stmt);
+ vn_reference_t vnresult;
+ val = vn_reference_lookup (lhs, gimple_vuse (stmt), VN_WALKREWRITE,
+ &vnresult, false);
+ if (TREE_CODE (rhs) == SSA_NAME)
+ rhs = VN_INFO (rhs)->valnum;
+ if (val
+ && operand_equal_p (val, rhs, 0))
+ {
+ /* We can only remove the later store if the former aliases
+ at least all accesses the later one does or if the store
+ was to readonly memory storing the same value. */
+ alias_set_type set = get_alias_set (lhs);
+ if (! vnresult
+ || vnresult->set == set
+ || alias_set_subset_of (set, vnresult->set))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Deleted redundant store ");
+ print_gimple_stmt (dump_file, stmt, 0);
+ }
+
+ /* Queue stmt for removal. */
+ to_remove.safe_push (stmt);
+ continue;
+ }
+ }
+ }
+
+ /* If this is a control statement value numbering left edges
+ unexecuted on force the condition in a way consistent with
+ that. */
+ if (gcond *cond = dyn_cast <gcond *> (stmt))
+ {
+ if ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE)
+ ^ (EDGE_SUCC (b, 1)->flags & EDGE_EXECUTABLE))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Removing unexecutable edge from ");
+ print_gimple_stmt (dump_file, stmt, 0);
+ }
+ if (((EDGE_SUCC (b, 0)->flags & EDGE_TRUE_VALUE) != 0)
+ == ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE) != 0))
+ gimple_cond_make_true (cond);
+ else
+ gimple_cond_make_false (cond);
+ update_stmt (cond);
+ el_todo |= TODO_cleanup_cfg;
+ continue;
+ }
+ }
+
+ bool can_make_abnormal_goto = stmt_can_make_abnormal_goto (stmt);
+ bool was_noreturn = (is_gimple_call (stmt)
+ && gimple_call_noreturn_p (stmt));
+ tree vdef = gimple_vdef (stmt);
+ tree vuse = gimple_vuse (stmt);
+
+ /* If we didn't replace the whole stmt (or propagate the result
+ into all uses), replace all uses on this stmt with their
+ leaders. */
+ bool modified = false;
+ use_operand_p use_p;
+ ssa_op_iter iter;
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+ {
+ tree use = USE_FROM_PTR (use_p);
+ /* ??? The call code above leaves stmt operands un-updated. */
+ if (TREE_CODE (use) != SSA_NAME)
+ continue;
+ tree sprime = eliminate_avail (use);
+ if (sprime && sprime != use
+ && may_propagate_copy (use, sprime)
+ /* We substitute into debug stmts to avoid excessive
+ debug temporaries created by removed stmts, but we need
+ to avoid doing so for inserted sprimes as we never want
+ to create debug temporaries for them. */
+ && (!inserted_exprs
+ || TREE_CODE (sprime) != SSA_NAME
+ || !is_gimple_debug (stmt)
+ || !bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (sprime))))
+ {
+ propagate_value (use_p, sprime);
+ modified = true;
+ }
+ }
+
+ /* Fold the stmt if modified, this canonicalizes MEM_REFs we propagated
+ into which is a requirement for the IPA devirt machinery. */
+ gimple *old_stmt = stmt;
+ if (modified)
+ {
+ /* If a formerly non-invariant ADDR_EXPR is turned into an
+ invariant one it was on a separate stmt. */
+ if (gimple_assign_single_p (stmt)
+ && TREE_CODE (gimple_assign_rhs1 (stmt)) == ADDR_EXPR)
+ recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
+ gimple_stmt_iterator prev = gsi;
+ gsi_prev (&prev);
+ if (fold_stmt (&gsi))
+ {
+ /* fold_stmt may have created new stmts inbetween
+ the previous stmt and the folded stmt. Mark
+ all defs created there as varying to not confuse
+ the SCCVN machinery as we're using that even during
+ elimination. */
+ if (gsi_end_p (prev))
+ prev = gsi_start_bb (b);
+ else
+ gsi_next (&prev);
+ if (gsi_stmt (prev) != gsi_stmt (gsi))
+ do
+ {
+ tree def;
+ ssa_op_iter dit;
+ FOR_EACH_SSA_TREE_OPERAND (def, gsi_stmt (prev),
+ dit, SSA_OP_ALL_DEFS)
+ /* As existing DEFs may move between stmts
+ we have to guard VN_INFO_GET. */
+ if (! has_VN_INFO (def))
+ VN_INFO_GET (def)->valnum = def;
+ if (gsi_stmt (prev) == gsi_stmt (gsi))
+ break;
+ gsi_next (&prev);
+ }
+ while (1);
+ }
+ stmt = gsi_stmt (gsi);
+ /* In case we folded the stmt away schedule the NOP for removal. */
+ if (gimple_nop_p (stmt))
+ to_remove.safe_push (stmt);
+ }
+
+ /* Visit indirect calls and turn them into direct calls if
+ possible using the devirtualization machinery. Do this before
+ checking for required EH/abnormal/noreturn cleanup as devird
+ may expose more of those. */
+ if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
+ {
+ tree fn = gimple_call_fn (call_stmt);
+ if (fn
+ && flag_devirtualize
+ && virtual_method_call_p (fn))
+ {
+ tree otr_type = obj_type_ref_class (fn);
+ unsigned HOST_WIDE_INT otr_tok
+ = tree_to_uhwi (OBJ_TYPE_REF_TOKEN (fn));
+ tree instance;
+ ipa_polymorphic_call_context context (current_function_decl,
+ fn, stmt, &instance);
+ context.get_dynamic_type (instance, OBJ_TYPE_REF_OBJECT (fn),
+ otr_type, stmt);
+ bool final;
+ vec <cgraph_node *> targets
+ = possible_polymorphic_call_targets (obj_type_ref_class (fn),
+ otr_tok, context, &final);
+ if (dump_file)
+ dump_possible_polymorphic_call_targets (dump_file,
+ obj_type_ref_class (fn),
+ otr_tok, context);
+ if (final && targets.length () <= 1 && dbg_cnt (devirt))
+ {
+ tree fn;
+ if (targets.length () == 1)
+ fn = targets[0]->decl;
+ else
+ fn = builtin_decl_implicit (BUILT_IN_UNREACHABLE);
+ if (dump_enabled_p ())
+ {
+ location_t loc = gimple_location (stmt);
+ dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc,
+ "converting indirect call to "
+ "function %s\n",
+ lang_hooks.decl_printable_name (fn, 2));
+ }
+ gimple_call_set_fndecl (call_stmt, fn);
+ /* If changing the call to __builtin_unreachable
+ or similar noreturn function, adjust gimple_call_fntype
+ too. */
+ if (gimple_call_noreturn_p (call_stmt)
+ && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fn)))
+ && TYPE_ARG_TYPES (TREE_TYPE (fn))
+ && (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fn)))
+ == void_type_node))
+ gimple_call_set_fntype (call_stmt, TREE_TYPE (fn));
+ maybe_remove_unused_call_args (cfun, call_stmt);
+ modified = true;
+ }
+ }
+ }
+
+ if (modified)
+ {
+ /* When changing a call into a noreturn call, cfg cleanup
+ is needed to fix up the noreturn call. */
+ if (!was_noreturn
+ && is_gimple_call (stmt) && gimple_call_noreturn_p (stmt))
+ to_fixup.safe_push (stmt);
+ /* When changing a condition or switch into one we know what
+ edge will be executed, schedule a cfg cleanup. */
+ if ((gimple_code (stmt) == GIMPLE_COND
+ && (gimple_cond_true_p (as_a <gcond *> (stmt))
+ || gimple_cond_false_p (as_a <gcond *> (stmt))))
+ || (gimple_code (stmt) == GIMPLE_SWITCH
+ && TREE_CODE (gimple_switch_index
+ (as_a <gswitch *> (stmt))) == INTEGER_CST))
+ el_todo |= TODO_cleanup_cfg;
+ /* If we removed EH side-effects from the statement, clean
+ its EH information. */
+ if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
+ {
+ bitmap_set_bit (need_eh_cleanup,
+ gimple_bb (stmt)->index);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " Removed EH side-effects.\n");
+ }
+ /* Likewise for AB side-effects. */
+ if (can_make_abnormal_goto
+ && !stmt_can_make_abnormal_goto (stmt))
+ {
+ bitmap_set_bit (need_ab_cleanup,
+ gimple_bb (stmt)->index);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " Removed AB side-effects.\n");
+ }
+ update_stmt (stmt);
+ if (vdef != gimple_vdef (stmt))
+ VN_INFO (vdef)->valnum = vuse;
+ }
+
+ /* Make new values available - for fully redundant LHS we
+ continue with the next stmt above and skip this. */
+ def_operand_p defp;
+ FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
+ eliminate_push_avail (DEF_FROM_PTR (defp));
+ }
+
+ /* Replace destination PHI arguments. */
+ FOR_EACH_EDGE (e, ei, b->succs)
+ if (e->flags & EDGE_EXECUTABLE)
+ for (gphi_iterator gsi = gsi_start_phis (e->dest);
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ {
+ gphi *phi = gsi.phi ();
+ use_operand_p use_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e);
+ tree arg = USE_FROM_PTR (use_p);
+ if (TREE_CODE (arg) != SSA_NAME
+ || virtual_operand_p (arg))
+ continue;
+ tree sprime = eliminate_avail (arg);
+ if (sprime && may_propagate_copy (arg, sprime))
+ propagate_value (use_p, sprime);
+ }
+ return NULL;
+}
+
+/* Make no longer available leaders no longer available. */
+
+void
+eliminate_dom_walker::after_dom_children (basic_block)
+{
+ tree entry;
+ while ((entry = avail_stack.pop ()) != NULL_TREE)
+ {
+ tree valnum = VN_INFO (entry)->valnum;
+ tree old = avail[SSA_NAME_VERSION (valnum)];
+ if (old == entry)
+ avail[SSA_NAME_VERSION (valnum)] = NULL_TREE;
+ else
+ avail[SSA_NAME_VERSION (valnum)] = entry;
+ }
+}
+
+/* Eliminate fully redundant computations. */
+
+unsigned int
+vn_eliminate (bitmap inserted_exprs)
+{
+ eliminate_dom_walker el (CDI_DOMINATORS, inserted_exprs);
+ el.avail.reserve (num_ssa_names);
+
+ el.walk (cfun->cfg->x_entry_block_ptr);
+
+ /* We cannot remove stmts during BB walk, especially not release SSA
+ names there as this confuses the VN machinery. The stmts ending
+ up in to_remove are either stores or simple copies.
+ Remove stmts in reverse order to make debug stmt creation possible. */
+ while (!el.to_remove.is_empty ())
+ {
+ gimple *stmt = el.to_remove.pop ();
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Removing dead stmt ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
+
+ gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
+ if (gimple_code (stmt) == GIMPLE_PHI)
+ remove_phi_node (&gsi, true);
+ else
+ {
+ basic_block bb = gimple_bb (stmt);
+ unlink_stmt_vdef (stmt);
+ if (gsi_remove (&gsi, true))
+ bitmap_set_bit (el.need_eh_cleanup, bb->index);
+ if (is_gimple_call (stmt) && stmt_can_make_abnormal_goto (stmt))
+ bitmap_set_bit (el.need_ab_cleanup, bb->index);
+ release_defs (stmt);
+ }
+
+ /* Removing a stmt may expose a forwarder block. */
+ el.el_todo |= TODO_cleanup_cfg;
+ }
+
+ /* Fixup stmts that became noreturn calls. This may require splitting
+ blocks and thus isn't possible during the dominator walk. Do this
+ in reverse order so we don't inadvertedly remove a stmt we want to
+ fixup by visiting a dominating now noreturn call first. */
+ while (!el.to_fixup.is_empty ())
+ {
+ gimple *stmt = el.to_fixup.pop ();
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Fixing up noreturn call ");
+ print_gimple_stmt (dump_file, stmt, 0);
+ }
+
+ if (fixup_noreturn_call (stmt))
+ el.el_todo |= TODO_cleanup_cfg;
+ }
+
+ bool do_eh_cleanup = !bitmap_empty_p (el.need_eh_cleanup);
+ bool do_ab_cleanup = !bitmap_empty_p (el.need_ab_cleanup);
+
+ if (do_eh_cleanup)
+ gimple_purge_all_dead_eh_edges (el.need_eh_cleanup);
+
+ if (do_ab_cleanup)
+ gimple_purge_all_dead_abnormal_call_edges (el.need_ab_cleanup);
+
+ if (do_eh_cleanup || do_ab_cleanup)
+ el.el_todo |= TODO_cleanup_cfg;
+
+ statistics_counter_event (cfun, "Eliminated", el.eliminations);
+ statistics_counter_event (cfun, "Insertions", el.insertions);
+
+ return el.el_todo;
+}
+
+
+namespace {
+
+const pass_data pass_data_fre =
+{
+ GIMPLE_PASS, /* type */
+ "fre", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_TREE_FRE, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+};
+
+class pass_fre : public gimple_opt_pass
+{
+public:
+ pass_fre (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_fre, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ opt_pass * clone () { return new pass_fre (m_ctxt); }
+ virtual bool gate (function *) { return flag_tree_fre != 0; }
+ virtual unsigned int execute (function *);
+
+}; // class pass_fre
+
+unsigned int
+pass_fre::execute (function *)
+{
+ unsigned int todo = 0;
+
+ run_scc_vn (VN_WALKREWRITE);
+
+ /* Remove all the redundant expressions. */
+ todo |= vn_eliminate (NULL);
+
+ scc_vn_restore_ssa_info ();
+ free_scc_vn ();
+
+ return todo;
+}
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_fre (gcc::context *ctxt)
+{
+ return new pass_fre (ctxt);
+}
projects / gcc.git / commitdiff