2 Copyright (C) 2003-2020 Free Software Foundation, Inc.
3 Contributed by Dorit Naishlos <dorit@il.ibm.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* Loop and basic block vectorizer.
23 This file contains drivers for the three vectorizers:
24 (1) loop vectorizer (inter-iteration parallelism),
25 (2) loop-aware SLP (intra-iteration parallelism) (invoked by the loop
27 (3) BB vectorizer (out-of-loops), aka SLP
29 The rest of the vectorizer's code is organized as follows:
30 - tree-vect-loop.c - loop specific parts such as reductions, etc. These are
31 used by drivers (1) and (2).
32 - tree-vect-loop-manip.c - vectorizer's loop control-flow utilities, used by
34 - tree-vect-slp.c - BB vectorization specific analysis and transformation,
35 used by drivers (2) and (3).
36 - tree-vect-stmts.c - statements analysis and transformation (used by all).
37 - tree-vect-data-refs.c - vectorizer specific data-refs analysis and
38 manipulations (used by all).
39 - tree-vect-patterns.c - vectorizable code patterns detector (used by all)
41 Here's a poor attempt at illustrating that:
44 loop_vect() loop_aware_slp() slp_vect()
47 tree-vect-loop.c tree-vect-slp.c
52 tree-vect-stmts.c tree-vect-data-refs.c
59 #include "coretypes.h"
64 #include "tree-pass.h"
67 #include "fold-const.h"
68 #include "stor-layout.h"
69 #include "gimple-iterator.h"
70 #include "gimple-walk.h"
71 #include "tree-ssa-loop-manip.h"
72 #include "tree-ssa-loop-niter.h"
75 #include "tree-vectorizer.h"
76 #include "tree-ssa-propagate.h"
78 #include "tree-scalar-evolution.h"
79 #include "stringpool.h"
81 #include "gimple-pretty-print.h"
82 #include "opt-problem.h"
83 #include "internal-fn.h"
86 /* Loop or bb location, with hotness information. */
87 dump_user_location_t vect_location;
89 /* auto_purge_vect_location's dtor: reset the vect_location
90 global, to avoid stale location_t values that could reference
93 auto_purge_vect_location::~auto_purge_vect_location ()
95 vect_location = dump_user_location_t ();
98 /* Dump a cost entry according to args to F. */
101 dump_stmt_cost (FILE *f, void *data, int count, enum vect_cost_for_stmt kind,
102 stmt_vec_info stmt_info, tree, int misalign, unsigned cost,
103 enum vect_cost_model_location where)
105 fprintf (f, "%p ", data);
108 print_gimple_expr (f, STMT_VINFO_STMT (stmt_info), 0, TDF_SLIM);
112 fprintf (f, "<unknown> ");
113 fprintf (f, "%d times ", count);
114 const char *ks = "unknown";
132 case vector_gather_load:
133 ks = "vector_gather_load";
136 ks = "unaligned_load";
138 case unaligned_store:
139 ks = "unaligned_store";
144 case vector_scatter_store:
145 ks = "vector_scatter_store";
148 ks = "vec_to_scalar";
151 ks = "scalar_to_vec";
153 case cond_branch_not_taken:
154 ks = "cond_branch_not_taken";
156 case cond_branch_taken:
157 ks = "cond_branch_taken";
162 case vec_promote_demote:
163 ks = "vec_promote_demote";
166 ks = "vec_construct";
169 fprintf (f, "%s ", ks);
170 if (kind == unaligned_load || kind == unaligned_store)
171 fprintf (f, "(misalign %d) ", misalign);
172 fprintf (f, "costs %u ", cost);
173 const char *ws = "unknown";
186 fprintf (f, "in %s\n", ws);
189 /* For mapping simduid to vectorization factor. */
191 class simduid_to_vf : public free_ptr_hash<simduid_to_vf>
194 unsigned int simduid;
197 /* hash_table support. */
198 static inline hashval_t hash (const simduid_to_vf *);
199 static inline int equal (const simduid_to_vf *, const simduid_to_vf *);
203 simduid_to_vf::hash (const simduid_to_vf *p)
209 simduid_to_vf::equal (const simduid_to_vf *p1, const simduid_to_vf *p2)
211 return p1->simduid == p2->simduid;
214 /* This hash maps the OMP simd array to the corresponding simduid used
215 to index into it. Like thus,
217 _7 = GOMP_SIMD_LANE (simduid.0)
223 This hash maps from the OMP simd array (D.1737[]) to DECL_UID of
226 struct simd_array_to_simduid : free_ptr_hash<simd_array_to_simduid>
229 unsigned int simduid;
231 /* hash_table support. */
232 static inline hashval_t hash (const simd_array_to_simduid *);
233 static inline int equal (const simd_array_to_simduid *,
234 const simd_array_to_simduid *);
238 simd_array_to_simduid::hash (const simd_array_to_simduid *p)
240 return DECL_UID (p->decl);
244 simd_array_to_simduid::equal (const simd_array_to_simduid *p1,
245 const simd_array_to_simduid *p2)
247 return p1->decl == p2->decl;
250 /* Fold IFN_GOMP_SIMD_LANE, IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LAST_LANE,
251 into their corresponding constants and remove
252 IFN_GOMP_SIMD_ORDERED_{START,END}. */
255 adjust_simduid_builtins (hash_table<simduid_to_vf> *htab)
259 FOR_EACH_BB_FN (bb, cfun)
261 gimple_stmt_iterator i;
263 for (i = gsi_start_bb (bb); !gsi_end_p (i); )
266 enum internal_fn ifn;
267 gimple *stmt = gsi_stmt (i);
269 if (!is_gimple_call (stmt)
270 || !gimple_call_internal_p (stmt))
275 ifn = gimple_call_internal_fn (stmt);
278 case IFN_GOMP_SIMD_LANE:
279 case IFN_GOMP_SIMD_VF:
280 case IFN_GOMP_SIMD_LAST_LANE:
282 case IFN_GOMP_SIMD_ORDERED_START:
283 case IFN_GOMP_SIMD_ORDERED_END:
284 if (integer_onep (gimple_call_arg (stmt, 0)))
286 enum built_in_function bcode
287 = (ifn == IFN_GOMP_SIMD_ORDERED_START
288 ? BUILT_IN_GOMP_ORDERED_START
289 : BUILT_IN_GOMP_ORDERED_END);
291 = gimple_build_call (builtin_decl_explicit (bcode), 0);
292 gimple_move_vops (g, stmt);
293 gsi_replace (&i, g, true);
296 gsi_remove (&i, true);
297 unlink_stmt_vdef (stmt);
303 tree arg = gimple_call_arg (stmt, 0);
304 gcc_assert (arg != NULL_TREE);
305 gcc_assert (TREE_CODE (arg) == SSA_NAME);
306 simduid_to_vf *p = NULL, data;
307 data.simduid = DECL_UID (SSA_NAME_VAR (arg));
308 /* Need to nullify loop safelen field since it's value is not
309 valid after transformation. */
310 if (bb->loop_father && bb->loop_father->safelen > 0)
311 bb->loop_father->safelen = 0;
314 p = htab->find (&data);
320 case IFN_GOMP_SIMD_VF:
321 t = build_int_cst (unsigned_type_node, vf);
323 case IFN_GOMP_SIMD_LANE:
324 t = build_int_cst (unsigned_type_node, 0);
326 case IFN_GOMP_SIMD_LAST_LANE:
327 t = gimple_call_arg (stmt, 1);
332 tree lhs = gimple_call_lhs (stmt);
334 replace_uses_by (lhs, t);
336 gsi_remove (&i, true);
341 /* Helper structure for note_simd_array_uses. */
343 struct note_simd_array_uses_struct
345 hash_table<simd_array_to_simduid> **htab;
346 unsigned int simduid;
349 /* Callback for note_simd_array_uses, called through walk_gimple_op. */
352 note_simd_array_uses_cb (tree *tp, int *walk_subtrees, void *data)
354 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
355 struct note_simd_array_uses_struct *ns
356 = (struct note_simd_array_uses_struct *) wi->info;
361 && lookup_attribute ("omp simd array", DECL_ATTRIBUTES (*tp))
362 && DECL_CONTEXT (*tp) == current_function_decl)
364 simd_array_to_simduid data;
366 *ns->htab = new hash_table<simd_array_to_simduid> (15);
368 data.simduid = ns->simduid;
369 simd_array_to_simduid **slot = (*ns->htab)->find_slot (&data, INSERT);
372 simd_array_to_simduid *p = XNEW (simd_array_to_simduid);
376 else if ((*slot)->simduid != ns->simduid)
377 (*slot)->simduid = -1U;
383 /* Find "omp simd array" temporaries and map them to corresponding
387 note_simd_array_uses (hash_table<simd_array_to_simduid> **htab)
390 gimple_stmt_iterator gsi;
391 struct walk_stmt_info wi;
392 struct note_simd_array_uses_struct ns;
394 memset (&wi, 0, sizeof (wi));
398 FOR_EACH_BB_FN (bb, cfun)
399 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
401 gimple *stmt = gsi_stmt (gsi);
402 if (!is_gimple_call (stmt) || !gimple_call_internal_p (stmt))
404 switch (gimple_call_internal_fn (stmt))
406 case IFN_GOMP_SIMD_LANE:
407 case IFN_GOMP_SIMD_VF:
408 case IFN_GOMP_SIMD_LAST_LANE:
413 tree lhs = gimple_call_lhs (stmt);
414 if (lhs == NULL_TREE)
416 imm_use_iterator use_iter;
418 ns.simduid = DECL_UID (SSA_NAME_VAR (gimple_call_arg (stmt, 0)));
419 FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, lhs)
420 if (!is_gimple_debug (use_stmt))
421 walk_gimple_op (use_stmt, note_simd_array_uses_cb, &wi);
425 /* Shrink arrays with "omp simd array" attribute to the corresponding
426 vectorization factor. */
430 (hash_table<simd_array_to_simduid> *simd_array_to_simduid_htab,
431 hash_table<simduid_to_vf> *simduid_to_vf_htab)
433 for (hash_table<simd_array_to_simduid>::iterator iter
434 = simd_array_to_simduid_htab->begin ();
435 iter != simd_array_to_simduid_htab->end (); ++iter)
436 if ((*iter)->simduid != -1U)
438 tree decl = (*iter)->decl;
440 if (simduid_to_vf_htab)
442 simduid_to_vf *p = NULL, data;
443 data.simduid = (*iter)->simduid;
444 p = simduid_to_vf_htab->find (&data);
449 = build_array_type_nelts (TREE_TYPE (TREE_TYPE (decl)), vf);
450 TREE_TYPE (decl) = atype;
451 relayout_decl (decl);
454 delete simd_array_to_simduid_htab;
457 /* Initialize the vec_info with kind KIND_IN and target cost data
458 TARGET_COST_DATA_IN. */
460 vec_info::vec_info (vec_info::vec_kind kind_in, void *target_cost_data_in,
461 vec_info_shared *shared_)
464 stmt_vec_info_ro (false),
465 target_cost_data (target_cost_data_in)
467 stmt_vec_infos.create (50);
470 vec_info::~vec_info ()
472 slp_instance instance;
475 FOR_EACH_VEC_ELT (slp_instances, i, instance)
476 vect_free_slp_instance (instance, true);
478 destroy_cost_data (target_cost_data);
479 free_stmt_vec_infos ();
482 vec_info_shared::vec_info_shared ()
484 datarefs_copy (vNULL),
489 vec_info_shared::~vec_info_shared ()
491 free_data_refs (datarefs);
492 free_dependence_relations (ddrs);
493 datarefs_copy.release ();
497 vec_info_shared::save_datarefs ()
501 datarefs_copy.reserve_exact (datarefs.length ());
502 for (unsigned i = 0; i < datarefs.length (); ++i)
503 datarefs_copy.quick_push (*datarefs[i]);
507 vec_info_shared::check_datarefs ()
511 gcc_assert (datarefs.length () == datarefs_copy.length ());
512 for (unsigned i = 0; i < datarefs.length (); ++i)
513 if (memcmp (&datarefs_copy[i], datarefs[i], sizeof (data_reference)) != 0)
517 /* Record that STMT belongs to the vectorizable region. Create and return
518 an associated stmt_vec_info. */
521 vec_info::add_stmt (gimple *stmt)
523 stmt_vec_info res = new_stmt_vec_info (stmt);
524 set_vinfo_for_stmt (stmt, res);
528 /* If STMT has an associated stmt_vec_info, return that vec_info, otherwise
529 return null. It is safe to call this function on any statement, even if
530 it might not be part of the vectorizable region. */
533 vec_info::lookup_stmt (gimple *stmt)
535 unsigned int uid = gimple_uid (stmt);
536 if (uid > 0 && uid - 1 < stmt_vec_infos.length ())
538 stmt_vec_info res = stmt_vec_infos[uid - 1];
539 if (res && res->stmt == stmt)
545 /* If NAME is an SSA_NAME and its definition has an associated stmt_vec_info,
546 return that stmt_vec_info, otherwise return null. It is safe to call
547 this on arbitrary operands. */
550 vec_info::lookup_def (tree name)
552 if (TREE_CODE (name) == SSA_NAME
553 && !SSA_NAME_IS_DEFAULT_DEF (name))
554 return lookup_stmt (SSA_NAME_DEF_STMT (name));
558 /* See whether there is a single non-debug statement that uses LHS and
559 whether that statement has an associated stmt_vec_info. Return the
560 stmt_vec_info if so, otherwise return null. */
563 vec_info::lookup_single_use (tree lhs)
567 if (single_imm_use (lhs, &dummy, &use_stmt))
568 return lookup_stmt (use_stmt);
572 /* Return vectorization information about DR. */
575 vec_info::lookup_dr (data_reference *dr)
577 stmt_vec_info stmt_info = lookup_stmt (DR_STMT (dr));
578 /* DR_STMT should never refer to a stmt in a pattern replacement. */
579 gcc_checking_assert (!is_pattern_stmt_p (stmt_info));
580 return STMT_VINFO_DR_INFO (stmt_info->dr_aux.stmt);
583 /* Record that NEW_STMT_INFO now implements the same data reference
587 vec_info::move_dr (stmt_vec_info new_stmt_info, stmt_vec_info old_stmt_info)
589 gcc_assert (!is_pattern_stmt_p (old_stmt_info));
590 STMT_VINFO_DR_INFO (old_stmt_info)->stmt = new_stmt_info;
591 new_stmt_info->dr_aux = old_stmt_info->dr_aux;
592 STMT_VINFO_DR_WRT_VEC_LOOP (new_stmt_info)
593 = STMT_VINFO_DR_WRT_VEC_LOOP (old_stmt_info);
594 STMT_VINFO_GATHER_SCATTER_P (new_stmt_info)
595 = STMT_VINFO_GATHER_SCATTER_P (old_stmt_info);
598 /* Permanently remove the statement described by STMT_INFO from the
602 vec_info::remove_stmt (stmt_vec_info stmt_info)
604 gcc_assert (!stmt_info->pattern_stmt_p);
605 set_vinfo_for_stmt (stmt_info->stmt, NULL);
606 gimple_stmt_iterator si = gsi_for_stmt (stmt_info->stmt);
607 unlink_stmt_vdef (stmt_info->stmt);
608 gsi_remove (&si, true);
609 release_defs (stmt_info->stmt);
610 free_stmt_vec_info (stmt_info);
613 /* Replace the statement at GSI by NEW_STMT, both the vectorization
614 information and the function itself. STMT_INFO describes the statement
618 vec_info::replace_stmt (gimple_stmt_iterator *gsi, stmt_vec_info stmt_info,
621 gimple *old_stmt = stmt_info->stmt;
622 gcc_assert (!stmt_info->pattern_stmt_p && old_stmt == gsi_stmt (*gsi));
623 gimple_set_uid (new_stmt, gimple_uid (old_stmt));
624 stmt_info->stmt = new_stmt;
625 gsi_replace (gsi, new_stmt, true);
628 /* Insert stmts in SEQ on the VEC_INFO region entry. If CONTEXT is
629 not NULL it specifies whether to use the sub-region entry
630 determined by it, currently used for loop vectorization to insert
631 on the inner loop entry vs. the outer loop entry. */
634 vec_info::insert_seq_on_entry (stmt_vec_info context, gimple_seq seq)
636 if (loop_vec_info loop_vinfo = dyn_cast <loop_vec_info> (this))
638 class loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
642 if (context && nested_in_vect_loop_p (loop, context))
645 pe = loop_preheader_edge (loop);
646 new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
647 gcc_assert (!new_bb);
651 bb_vec_info bb_vinfo = as_a <bb_vec_info> (this);
652 gimple_stmt_iterator gsi_region_begin = bb_vinfo->region_begin;
653 gsi_insert_seq_before (&gsi_region_begin, seq, GSI_SAME_STMT);
657 /* Like insert_seq_on_entry but just inserts the single stmt NEW_STMT. */
660 vec_info::insert_on_entry (stmt_vec_info context, gimple *new_stmt)
662 gimple_seq seq = NULL;
663 gimple_stmt_iterator gsi = gsi_start (seq);
664 gsi_insert_before_without_update (&gsi, new_stmt, GSI_SAME_STMT);
665 insert_seq_on_entry (context, seq);
668 /* Create and initialize a new stmt_vec_info struct for STMT. */
671 vec_info::new_stmt_vec_info (gimple *stmt)
673 stmt_vec_info res = XCNEW (class _stmt_vec_info);
676 STMT_VINFO_TYPE (res) = undef_vec_info_type;
677 STMT_VINFO_RELEVANT (res) = vect_unused_in_scope;
678 STMT_VINFO_VECTORIZABLE (res) = true;
679 STMT_VINFO_REDUC_TYPE (res) = TREE_CODE_REDUCTION;
680 STMT_VINFO_REDUC_CODE (res) = ERROR_MARK;
681 STMT_VINFO_REDUC_FN (res) = IFN_LAST;
682 STMT_VINFO_REDUC_IDX (res) = -1;
683 STMT_VINFO_SLP_VECT_ONLY (res) = false;
684 STMT_VINFO_VEC_STMTS (res) = vNULL;
686 if (gimple_code (stmt) == GIMPLE_PHI
687 && is_loop_header_bb_p (gimple_bb (stmt)))
688 STMT_VINFO_DEF_TYPE (res) = vect_unknown_def_type;
690 STMT_VINFO_DEF_TYPE (res) = vect_internal_def;
692 STMT_VINFO_SAME_ALIGN_REFS (res).create (0);
693 STMT_SLP_TYPE (res) = loop_vect;
695 /* This is really "uninitialized" until vect_compute_data_ref_alignment. */
696 res->dr_aux.misalignment = DR_MISALIGNMENT_UNINITIALIZED;
701 /* Associate STMT with INFO. */
704 vec_info::set_vinfo_for_stmt (gimple *stmt, stmt_vec_info info)
706 unsigned int uid = gimple_uid (stmt);
709 gcc_assert (!stmt_vec_info_ro);
710 gcc_checking_assert (info);
711 uid = stmt_vec_infos.length () + 1;
712 gimple_set_uid (stmt, uid);
713 stmt_vec_infos.safe_push (info);
717 gcc_checking_assert (info == NULL);
718 stmt_vec_infos[uid - 1] = info;
722 /* Free the contents of stmt_vec_infos. */
725 vec_info::free_stmt_vec_infos (void)
729 FOR_EACH_VEC_ELT (stmt_vec_infos, i, info)
731 free_stmt_vec_info (info);
732 stmt_vec_infos.release ();
735 /* Free STMT_INFO. */
738 vec_info::free_stmt_vec_info (stmt_vec_info stmt_info)
740 if (stmt_info->pattern_stmt_p)
742 gimple_set_bb (stmt_info->stmt, NULL);
743 tree lhs = gimple_get_lhs (stmt_info->stmt);
744 if (lhs && TREE_CODE (lhs) == SSA_NAME)
745 release_ssa_name (lhs);
748 STMT_VINFO_SAME_ALIGN_REFS (stmt_info).release ();
749 STMT_VINFO_SIMD_CLONE_INFO (stmt_info).release ();
750 STMT_VINFO_VEC_STMTS (stmt_info).release ();
754 /* Returns true if S1 dominates S2. */
757 vect_stmt_dominates_stmt_p (gimple *s1, gimple *s2)
759 basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2);
761 /* If bb1 is NULL, it should be a GIMPLE_NOP def stmt of an (D)
762 SSA_NAME. Assume it lives at the beginning of function and
763 thus dominates everything. */
764 if (!bb1 || s1 == s2)
767 /* If bb2 is NULL, it doesn't dominate any stmt with a bb. */
772 return dominated_by_p (CDI_DOMINATORS, bb2, bb1);
774 /* PHIs in the same basic block are assumed to be
775 executed all in parallel, if only one stmt is a PHI,
776 it dominates the other stmt in the same basic block. */
777 if (gimple_code (s1) == GIMPLE_PHI)
780 if (gimple_code (s2) == GIMPLE_PHI)
783 /* Inserted vectorized stmts all have UID 0 while the original stmts
784 in the IL have UID increasing within a BB. Walk from both sides
785 until we find the other stmt or a stmt with UID != 0. */
786 gimple_stmt_iterator gsi1 = gsi_for_stmt (s1);
787 while (gimple_uid (gsi_stmt (gsi1)) == 0)
790 if (gsi_end_p (gsi1))
792 if (gsi_stmt (gsi1) == s2)
795 if (gimple_uid (gsi_stmt (gsi1)) == -1u)
798 gimple_stmt_iterator gsi2 = gsi_for_stmt (s2);
799 while (gimple_uid (gsi_stmt (gsi2)) == 0)
802 if (gsi_end_p (gsi2))
804 if (gsi_stmt (gsi2) == s1)
807 if (gimple_uid (gsi_stmt (gsi2)) == -1u)
810 if (gimple_uid (gsi_stmt (gsi1)) <= gimple_uid (gsi_stmt (gsi2)))
815 /* A helper function to free scev and LOOP niter information, as well as
816 clear loop constraint LOOP_C_FINITE. */
819 vect_free_loop_info_assumptions (class loop *loop)
822 /* We need to explicitly reset upper bound information since they are
823 used even after free_numbers_of_iterations_estimates. */
824 loop->any_upper_bound = false;
825 loop->any_likely_upper_bound = false;
826 free_numbers_of_iterations_estimates (loop);
827 loop_constraint_clear (loop, LOOP_C_FINITE);
830 /* If LOOP has been versioned during ifcvt, return the internal call
834 vect_loop_vectorized_call (class loop *loop, gcond **cond)
836 basic_block bb = loop_preheader_edge (loop)->src;
843 if (!single_pred_p (bb))
845 bb = single_pred (bb);
848 if (g && gimple_code (g) == GIMPLE_COND)
851 *cond = as_a <gcond *> (g);
852 gimple_stmt_iterator gsi = gsi_for_stmt (g);
854 if (!gsi_end_p (gsi))
857 if (gimple_call_internal_p (g, IFN_LOOP_VECTORIZED)
858 && (tree_to_shwi (gimple_call_arg (g, 0)) == loop->num
859 || tree_to_shwi (gimple_call_arg (g, 1)) == loop->num))
866 /* If LOOP has been versioned during loop distribution, return the gurading
870 vect_loop_dist_alias_call (class loop *loop)
874 class loop *outer, *orig;
875 gimple_stmt_iterator gsi;
878 if (loop->orig_loop_num == 0)
881 orig = get_loop (cfun, loop->orig_loop_num);
884 /* The original loop is somehow destroyed. Clear the information. */
885 loop->orig_loop_num = 0;
890 bb = nearest_common_dominator (CDI_DOMINATORS, loop->header, orig->header);
892 bb = loop_preheader_edge (loop)->src;
894 outer = bb->loop_father;
895 entry = ENTRY_BLOCK_PTR_FOR_FN (cfun);
897 /* Look upward in dominance tree. */
898 for (; bb != entry && flow_bb_inside_loop_p (outer, bb);
899 bb = get_immediate_dominator (CDI_DOMINATORS, bb))
902 if (g == NULL || gimple_code (g) != GIMPLE_COND)
905 gsi = gsi_for_stmt (g);
911 /* The guarding internal function call must have the same distribution
913 if (gimple_call_internal_p (g, IFN_LOOP_DIST_ALIAS)
914 && (tree_to_shwi (gimple_call_arg (g, 0)) == loop->orig_loop_num))
920 /* Set the uids of all the statements in basic blocks inside loop
921 represented by LOOP_VINFO. LOOP_VECTORIZED_CALL is the internal
922 call guarding the loop which has been if converted. */
924 set_uid_loop_bbs (loop_vec_info loop_vinfo, gimple *loop_vectorized_call)
926 tree arg = gimple_call_arg (loop_vectorized_call, 1);
929 class loop *scalar_loop = get_loop (cfun, tree_to_shwi (arg));
931 LOOP_VINFO_SCALAR_LOOP (loop_vinfo) = scalar_loop;
932 gcc_checking_assert (vect_loop_vectorized_call (scalar_loop)
933 == loop_vectorized_call);
934 /* If we are going to vectorize outer loop, prevent vectorization
935 of the inner loop in the scalar loop - either the scalar loop is
936 thrown away, so it is a wasted work, or is used only for
938 if (scalar_loop->inner)
940 gimple *g = vect_loop_vectorized_call (scalar_loop->inner);
943 arg = gimple_call_arg (g, 0);
944 get_loop (cfun, tree_to_shwi (arg))->dont_vectorize = true;
945 fold_loop_internal_call (g, boolean_false_node);
948 bbs = get_loop_body (scalar_loop);
949 for (i = 0; i < scalar_loop->num_nodes; i++)
951 basic_block bb = bbs[i];
952 gimple_stmt_iterator gsi;
953 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
955 gimple *phi = gsi_stmt (gsi);
956 gimple_set_uid (phi, 0);
958 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
960 gimple *stmt = gsi_stmt (gsi);
961 gimple_set_uid (stmt, 0);
967 /* Try to vectorize LOOP. */
970 try_vectorize_loop_1 (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
971 unsigned *num_vectorized_loops, loop_p loop,
972 gimple *loop_vectorized_call,
973 gimple *loop_dist_alias_call)
976 vec_info_shared shared;
977 auto_purge_vect_location sentinel;
978 vect_location = find_loop_location (loop);
980 if (LOCATION_LOCUS (vect_location.get_location_t ()) != UNKNOWN_LOCATION
981 && dump_enabled_p ())
982 dump_printf (MSG_NOTE | MSG_PRIORITY_INTERNALS,
983 "\nAnalyzing loop at %s:%d\n",
984 LOCATION_FILE (vect_location.get_location_t ()),
985 LOCATION_LINE (vect_location.get_location_t ()));
987 opt_loop_vec_info loop_vinfo = opt_loop_vec_info::success (NULL);
988 /* In the case of epilogue vectorization the loop already has its
989 loop_vec_info set, we do not require to analyze the loop in this case. */
990 if (loop_vec_info vinfo = loop_vec_info_for_loop (loop))
991 loop_vinfo = opt_loop_vec_info::success (vinfo);
994 /* Try to analyze the loop, retaining an opt_problem if dump_enabled_p. */
995 loop_vinfo = vect_analyze_loop (loop, &shared);
996 loop->aux = loop_vinfo;
1000 if (dump_enabled_p ())
1001 if (opt_problem *problem = loop_vinfo.get_problem ())
1003 dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
1004 "couldn't vectorize loop\n");
1005 problem->emit_and_clear ();
1008 if (!loop_vinfo || !LOOP_VINFO_VECTORIZABLE_P (loop_vinfo))
1010 /* Free existing information if loop is analyzed with some
1012 if (loop_constraint_set_p (loop, LOOP_C_FINITE))
1013 vect_free_loop_info_assumptions (loop);
1015 /* If we applied if-conversion then try to vectorize the
1016 BB of innermost loops.
1017 ??? Ideally BB vectorization would learn to vectorize
1018 control flow by applying if-conversion on-the-fly, the
1019 following retains the if-converted loop body even when
1020 only non-if-converted parts took part in BB vectorization. */
1021 if (flag_tree_slp_vectorize != 0
1022 && loop_vectorized_call
1025 basic_block bb = loop->header;
1026 bool require_loop_vectorize = false;
1027 for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
1028 !gsi_end_p (gsi); gsi_next (&gsi))
1030 gimple *stmt = gsi_stmt (gsi);
1031 gcall *call = dyn_cast <gcall *> (stmt);
1032 if (call && gimple_call_internal_p (call))
1034 internal_fn ifn = gimple_call_internal_fn (call);
1035 if (ifn == IFN_MASK_LOAD || ifn == IFN_MASK_STORE
1036 /* Don't keep the if-converted parts when the ifn with
1037 specifc type is not supported by the backend. */
1038 || (direct_internal_fn_p (ifn)
1039 && !direct_internal_fn_supported_p
1040 (call, OPTIMIZE_FOR_SPEED)))
1042 require_loop_vectorize = true;
1046 gimple_set_uid (stmt, -1);
1047 gimple_set_visited (stmt, false);
1049 if (!require_loop_vectorize && vect_slp_bb (bb))
1051 if (dump_enabled_p ())
1052 dump_printf_loc (MSG_NOTE, vect_location,
1053 "basic block vectorized\n");
1054 fold_loop_internal_call (loop_vectorized_call,
1056 loop_vectorized_call = NULL;
1057 ret |= TODO_cleanup_cfg | TODO_update_ssa_only_virtuals;
1060 /* If outer loop vectorization fails for LOOP_VECTORIZED guarded
1061 loop, don't vectorize its inner loop; we'll attempt to
1062 vectorize LOOP_VECTORIZED guarded inner loop of the scalar
1064 if (loop_vectorized_call && loop->inner)
1065 loop->inner->dont_vectorize = true;
1069 if (!dbg_cnt (vect_loop))
1071 /* Free existing information if loop is analyzed with some
1073 if (loop_constraint_set_p (loop, LOOP_C_FINITE))
1074 vect_free_loop_info_assumptions (loop);
1078 if (loop_vectorized_call)
1079 set_uid_loop_bbs (loop_vinfo, loop_vectorized_call);
1081 unsigned HOST_WIDE_INT bytes;
1082 if (dump_enabled_p ())
1084 if (GET_MODE_SIZE (loop_vinfo->vector_mode).is_constant (&bytes))
1085 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, vect_location,
1086 "loop vectorized using %wu byte vectors\n", bytes);
1088 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, vect_location,
1089 "loop vectorized using variable length vectors\n");
1092 loop_p new_loop = vect_transform_loop (loop_vinfo,
1093 loop_vectorized_call);
1094 (*num_vectorized_loops)++;
1095 /* Now that the loop has been vectorized, allow it to be unrolled
1097 loop->force_vectorize = false;
1101 simduid_to_vf *simduid_to_vf_data = XNEW (simduid_to_vf);
1102 if (!simduid_to_vf_htab)
1103 simduid_to_vf_htab = new hash_table<simduid_to_vf> (15);
1104 simduid_to_vf_data->simduid = DECL_UID (loop->simduid);
1105 simduid_to_vf_data->vf = loop_vinfo->vectorization_factor;
1106 *simduid_to_vf_htab->find_slot (simduid_to_vf_data, INSERT)
1107 = simduid_to_vf_data;
1110 if (loop_vectorized_call)
1112 fold_loop_internal_call (loop_vectorized_call, boolean_true_node);
1113 loop_vectorized_call = NULL;
1114 ret |= TODO_cleanup_cfg;
1116 if (loop_dist_alias_call)
1118 tree value = gimple_call_arg (loop_dist_alias_call, 1);
1119 fold_loop_internal_call (loop_dist_alias_call, value);
1120 loop_dist_alias_call = NULL;
1121 ret |= TODO_cleanup_cfg;
1124 /* Epilogue of vectorized loop must be vectorized too. */
1127 /* Don't include vectorized epilogues in the "vectorized loops" count.
1129 unsigned dont_count = *num_vectorized_loops;
1130 ret |= try_vectorize_loop_1 (simduid_to_vf_htab, &dont_count,
1131 new_loop, NULL, NULL);
1137 /* Try to vectorize LOOP. */
1140 try_vectorize_loop (hash_table<simduid_to_vf> *&simduid_to_vf_htab,
1141 unsigned *num_vectorized_loops, loop_p loop)
1143 if (!((flag_tree_loop_vectorize
1144 && optimize_loop_nest_for_speed_p (loop))
1145 || loop->force_vectorize))
1148 return try_vectorize_loop_1 (simduid_to_vf_htab, num_vectorized_loops, loop,
1149 vect_loop_vectorized_call (loop),
1150 vect_loop_dist_alias_call (loop));
1154 /* Function vectorize_loops.
1156 Entry point to loop vectorization phase. */
1159 vectorize_loops (void)
1162 unsigned int num_vectorized_loops = 0;
1163 unsigned int vect_loops_num;
1165 hash_table<simduid_to_vf> *simduid_to_vf_htab = NULL;
1166 hash_table<simd_array_to_simduid> *simd_array_to_simduid_htab = NULL;
1167 bool any_ifcvt_loops = false;
1170 vect_loops_num = number_of_loops (cfun);
1172 /* Bail out if there are no loops. */
1173 if (vect_loops_num <= 1)
1176 if (cfun->has_simduid_loops)
1177 note_simd_array_uses (&simd_array_to_simduid_htab);
1179 /* ----------- Analyze loops. ----------- */
1181 /* If some loop was duplicated, it gets bigger number
1182 than all previously defined loops. This fact allows us to run
1183 only over initial loops skipping newly generated ones. */
1184 FOR_EACH_LOOP (loop, 0)
1185 if (loop->dont_vectorize)
1187 any_ifcvt_loops = true;
1188 /* If-conversion sometimes versions both the outer loop
1189 (for the case when outer loop vectorization might be
1190 desirable) as well as the inner loop in the scalar version
1191 of the loop. So we have:
1192 if (LOOP_VECTORIZED (1, 3))
1198 loop3 (copy of loop1)
1199 if (LOOP_VECTORIZED (4, 5))
1200 loop4 (copy of loop2)
1202 loop5 (copy of loop4)
1203 If FOR_EACH_LOOP gives us loop3 first (which has
1204 dont_vectorize set), make sure to process loop1 before loop4;
1205 so that we can prevent vectorization of loop4 if loop1
1206 is successfully vectorized. */
1209 gimple *loop_vectorized_call
1210 = vect_loop_vectorized_call (loop);
1211 if (loop_vectorized_call
1212 && vect_loop_vectorized_call (loop->inner))
1214 tree arg = gimple_call_arg (loop_vectorized_call, 0);
1215 class loop *vector_loop
1216 = get_loop (cfun, tree_to_shwi (arg));
1217 if (vector_loop && vector_loop != loop)
1219 /* Make sure we don't vectorize it twice. */
1220 vector_loop->dont_vectorize = true;
1221 ret |= try_vectorize_loop (simduid_to_vf_htab,
1222 &num_vectorized_loops,
1229 ret |= try_vectorize_loop (simduid_to_vf_htab, &num_vectorized_loops,
1232 vect_location = dump_user_location_t ();
1234 statistics_counter_event (cfun, "Vectorized loops", num_vectorized_loops);
1235 if (dump_enabled_p ()
1236 || (num_vectorized_loops > 0 && dump_enabled_p ()))
1237 dump_printf_loc (MSG_NOTE, vect_location,
1238 "vectorized %u loops in function.\n",
1239 num_vectorized_loops);
1241 /* ----------- Finalize. ----------- */
1243 if (any_ifcvt_loops)
1244 for (i = 1; i < number_of_loops (cfun); i++)
1246 loop = get_loop (cfun, i);
1247 if (loop && loop->dont_vectorize)
1249 gimple *g = vect_loop_vectorized_call (loop);
1252 fold_loop_internal_call (g, boolean_false_node);
1253 ret |= TODO_cleanup_cfg;
1257 g = vect_loop_dist_alias_call (loop);
1261 fold_loop_internal_call (g, boolean_false_node);
1262 ret |= TODO_cleanup_cfg;
1267 for (i = 1; i < number_of_loops (cfun); i++)
1269 loop_vec_info loop_vinfo;
1270 bool has_mask_store;
1272 loop = get_loop (cfun, i);
1273 if (!loop || !loop->aux)
1275 loop_vinfo = (loop_vec_info) loop->aux;
1276 has_mask_store = LOOP_VINFO_HAS_MASK_STORE (loop_vinfo);
1279 && targetm.vectorize.empty_mask_is_expensive (IFN_MASK_STORE))
1280 optimize_mask_stores (loop);
1284 /* Fold IFN_GOMP_SIMD_{VF,LANE,LAST_LANE,ORDERED_{START,END}} builtins. */
1285 if (cfun->has_simduid_loops)
1286 adjust_simduid_builtins (simduid_to_vf_htab);
1288 /* Shrink any "omp array simd" temporary arrays to the
1289 actual vectorization factors. */
1290 if (simd_array_to_simduid_htab)
1291 shrink_simd_arrays (simd_array_to_simduid_htab, simduid_to_vf_htab);
1292 delete simduid_to_vf_htab;
1293 cfun->has_simduid_loops = false;
1295 if (num_vectorized_loops > 0)
1297 /* If we vectorized any loop only virtual SSA form needs to be updated.
1298 ??? Also while we try hard to update loop-closed SSA form we fail
1299 to properly do this in some corner-cases (see PR56286). */
1300 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa_only_virtuals);
1301 return TODO_cleanup_cfg;
1308 /* Entry point to the simduid cleanup pass. */
1312 const pass_data pass_data_simduid_cleanup =
1314 GIMPLE_PASS, /* type */
1315 "simduid", /* name */
1316 OPTGROUP_NONE, /* optinfo_flags */
1317 TV_NONE, /* tv_id */
1318 ( PROP_ssa | PROP_cfg ), /* properties_required */
1319 0, /* properties_provided */
1320 0, /* properties_destroyed */
1321 0, /* todo_flags_start */
1322 0, /* todo_flags_finish */
1325 class pass_simduid_cleanup : public gimple_opt_pass
1328 pass_simduid_cleanup (gcc::context *ctxt)
1329 : gimple_opt_pass (pass_data_simduid_cleanup, ctxt)
1332 /* opt_pass methods: */
1333 opt_pass * clone () { return new pass_simduid_cleanup (m_ctxt); }
1334 virtual bool gate (function *fun) { return fun->has_simduid_loops; }
1335 virtual unsigned int execute (function *);
1337 }; // class pass_simduid_cleanup
1340 pass_simduid_cleanup::execute (function *fun)
1342 hash_table<simd_array_to_simduid> *simd_array_to_simduid_htab = NULL;
1344 note_simd_array_uses (&simd_array_to_simduid_htab);
1346 /* Fold IFN_GOMP_SIMD_{VF,LANE,LAST_LANE,ORDERED_{START,END}} builtins. */
1347 adjust_simduid_builtins (NULL);
1349 /* Shrink any "omp array simd" temporary arrays to the
1350 actual vectorization factors. */
1351 if (simd_array_to_simduid_htab)
1352 shrink_simd_arrays (simd_array_to_simduid_htab, NULL);
1353 fun->has_simduid_loops = false;
1360 make_pass_simduid_cleanup (gcc::context *ctxt)
1362 return new pass_simduid_cleanup (ctxt);
1366 /* Entry point to basic block SLP phase. */
1370 const pass_data pass_data_slp_vectorize =
1372 GIMPLE_PASS, /* type */
1374 OPTGROUP_LOOP | OPTGROUP_VEC, /* optinfo_flags */
1375 TV_TREE_SLP_VECTORIZATION, /* tv_id */
1376 ( PROP_ssa | PROP_cfg ), /* properties_required */
1377 0, /* properties_provided */
1378 0, /* properties_destroyed */
1379 0, /* todo_flags_start */
1380 TODO_update_ssa, /* todo_flags_finish */
1383 class pass_slp_vectorize : public gimple_opt_pass
1386 pass_slp_vectorize (gcc::context *ctxt)
1387 : gimple_opt_pass (pass_data_slp_vectorize, ctxt)
1390 /* opt_pass methods: */
1391 opt_pass * clone () { return new pass_slp_vectorize (m_ctxt); }
1392 virtual bool gate (function *) { return flag_tree_slp_vectorize != 0; }
1393 virtual unsigned int execute (function *);
1395 }; // class pass_slp_vectorize
1398 pass_slp_vectorize::execute (function *fun)
1400 auto_purge_vect_location sentinel;
1403 bool in_loop_pipeline = scev_initialized_p ();
1404 if (!in_loop_pipeline)
1406 loop_optimizer_init (LOOPS_NORMAL);
1410 /* Mark all stmts as not belonging to the current region and unvisited. */
1411 FOR_EACH_BB_FN (bb, fun)
1413 for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
1416 gimple *stmt = gsi_stmt (gsi);
1417 gimple_set_uid (stmt, -1);
1418 gimple_set_visited (stmt, false);
1422 FOR_EACH_BB_FN (bb, fun)
1424 if (vect_slp_bb (bb))
1425 if (dump_enabled_p ())
1426 dump_printf_loc (MSG_NOTE, vect_location, "basic block vectorized\n");
1429 if (!in_loop_pipeline)
1432 loop_optimizer_finalize ();
1441 make_pass_slp_vectorize (gcc::context *ctxt)
1443 return new pass_slp_vectorize (ctxt);
1447 /* Increase alignment of global arrays to improve vectorization potential.
1449 - Consider also structs that have an array field.
1450 - Use ipa analysis to prune arrays that can't be vectorized?
1451 This should involve global alignment analysis and in the future also
1454 static unsigned get_vec_alignment_for_type (tree);
1455 static hash_map<tree, unsigned> *type_align_map;
1457 /* Return alignment of array's vector type corresponding to scalar type.
1458 0 if no vector type exists. */
1460 get_vec_alignment_for_array_type (tree type)
1462 gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
1463 poly_uint64 array_size, vector_size;
1465 tree scalar_type = strip_array_types (type);
1466 tree vectype = get_related_vectype_for_scalar_type (VOIDmode, scalar_type);
1468 || !poly_int_tree_p (TYPE_SIZE (type), &array_size)
1469 || !poly_int_tree_p (TYPE_SIZE (vectype), &vector_size)
1470 || maybe_lt (array_size, vector_size))
1473 return TYPE_ALIGN (vectype);
1476 /* Return alignment of field having maximum alignment of vector type
1477 corresponding to it's scalar type. For now, we only consider fields whose
1478 offset is a multiple of it's vector alignment.
1479 0 if no suitable field is found. */
1481 get_vec_alignment_for_record_type (tree type)
1483 gcc_assert (TREE_CODE (type) == RECORD_TYPE);
1485 unsigned max_align = 0, alignment;
1486 HOST_WIDE_INT offset;
1489 if (TYPE_PACKED (type))
1492 unsigned *slot = type_align_map->get (type);
1496 for (tree field = first_field (type);
1498 field = DECL_CHAIN (field))
1500 /* Skip if not FIELD_DECL or if alignment is set by user. */
1501 if (TREE_CODE (field) != FIELD_DECL
1502 || DECL_USER_ALIGN (field)
1503 || DECL_ARTIFICIAL (field))
1506 /* We don't need to process the type further if offset is variable,
1507 since the offsets of remaining members will also be variable. */
1508 if (TREE_CODE (DECL_FIELD_OFFSET (field)) != INTEGER_CST
1509 || TREE_CODE (DECL_FIELD_BIT_OFFSET (field)) != INTEGER_CST)
1512 /* Similarly stop processing the type if offset_tree
1513 does not fit in unsigned HOST_WIDE_INT. */
1514 offset_tree = bit_position (field);
1515 if (!tree_fits_uhwi_p (offset_tree))
1518 offset = tree_to_uhwi (offset_tree);
1519 alignment = get_vec_alignment_for_type (TREE_TYPE (field));
1521 /* Get maximum alignment of vectorized field/array among those members
1522 whose offset is multiple of the vector alignment. */
1524 && (offset % alignment == 0)
1525 && (alignment > max_align))
1526 max_align = alignment;
1529 type_align_map->put (type, max_align);
1533 /* Return alignment of vector type corresponding to decl's scalar type
1534 or 0 if it doesn't exist or the vector alignment is lesser than
1535 decl's alignment. */
1537 get_vec_alignment_for_type (tree type)
1539 if (type == NULL_TREE)
1542 gcc_assert (TYPE_P (type));
1544 static unsigned alignment = 0;
1545 switch (TREE_CODE (type))
1548 alignment = get_vec_alignment_for_array_type (type);
1551 alignment = get_vec_alignment_for_record_type (type);
1558 return (alignment > TYPE_ALIGN (type)) ? alignment : 0;
1561 /* Entry point to increase_alignment pass. */
1563 increase_alignment (void)
1565 varpool_node *vnode;
1567 vect_location = dump_user_location_t ();
1568 type_align_map = new hash_map<tree, unsigned>;
1570 /* Increase the alignment of all global arrays for vectorization. */
1571 FOR_EACH_DEFINED_VARIABLE (vnode)
1573 tree decl = vnode->decl;
1574 unsigned int alignment;
1576 if ((decl_in_symtab_p (decl)
1577 && !symtab_node::get (decl)->can_increase_alignment_p ())
1578 || DECL_USER_ALIGN (decl) || DECL_ARTIFICIAL (decl))
1581 alignment = get_vec_alignment_for_type (TREE_TYPE (decl));
1582 if (alignment && vect_can_force_dr_alignment_p (decl, alignment))
1584 vnode->increase_alignment (alignment);
1585 if (dump_enabled_p ())
1586 dump_printf (MSG_NOTE, "Increasing alignment of decl: %T\n", decl);
1590 delete type_align_map;
1597 const pass_data pass_data_ipa_increase_alignment =
1599 SIMPLE_IPA_PASS, /* type */
1600 "increase_alignment", /* name */
1601 OPTGROUP_LOOP | OPTGROUP_VEC, /* optinfo_flags */
1602 TV_IPA_OPT, /* tv_id */
1603 0, /* properties_required */
1604 0, /* properties_provided */
1605 0, /* properties_destroyed */
1606 0, /* todo_flags_start */
1607 0, /* todo_flags_finish */
1610 class pass_ipa_increase_alignment : public simple_ipa_opt_pass
1613 pass_ipa_increase_alignment (gcc::context *ctxt)
1614 : simple_ipa_opt_pass (pass_data_ipa_increase_alignment, ctxt)
1617 /* opt_pass methods: */
1618 virtual bool gate (function *)
1620 return flag_section_anchors && flag_tree_loop_vectorize;
1623 virtual unsigned int execute (function *) { return increase_alignment (); }
1625 }; // class pass_ipa_increase_alignment
1629 simple_ipa_opt_pass *
1630 make_pass_ipa_increase_alignment (gcc::context *ctxt)
1632 return new pass_ipa_increase_alignment (ctxt);
1635 /* If the condition represented by T is a comparison or the SSA name
1636 result of a comparison, extract the comparison's operands. Represent
1637 T as NE_EXPR <T, 0> otherwise. */
1640 scalar_cond_masked_key::get_cond_ops_from_tree (tree t)
1642 if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_comparison)
1644 this->code = TREE_CODE (t);
1645 this->op0 = TREE_OPERAND (t, 0);
1646 this->op1 = TREE_OPERAND (t, 1);
1650 if (TREE_CODE (t) == SSA_NAME)
1651 if (gassign *stmt = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (t)))
1653 tree_code code = gimple_assign_rhs_code (stmt);
1654 if (TREE_CODE_CLASS (code) == tcc_comparison)
1657 this->op0 = gimple_assign_rhs1 (stmt);
1658 this->op1 = gimple_assign_rhs2 (stmt);
1663 this->code = NE_EXPR;
1665 this->op1 = build_zero_cst (TREE_TYPE (t));