1 /* Analysis Utilities for Loop Vectorization.
2 Copyright (C) 2003,2004,2005 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 2, 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 COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-flow.h"
32 #include "tree-dump.h"
37 #include "tree-chrec.h"
38 #include "tree-data-ref.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-vectorizer.h"
42 /* Main analysis functions. */
43 static loop_vec_info vect_analyze_loop_form (struct loop *);
44 static bool vect_analyze_data_refs (loop_vec_info);
45 static bool vect_mark_stmts_to_be_vectorized (loop_vec_info);
46 static bool vect_analyze_scalar_cycles (loop_vec_info);
47 static bool vect_analyze_data_ref_accesses (loop_vec_info);
48 static bool vect_analyze_data_ref_dependences (loop_vec_info);
49 static bool vect_analyze_data_refs_alignment (loop_vec_info);
50 static bool vect_compute_data_refs_alignment (loop_vec_info);
51 static void vect_enhance_data_refs_alignment (loop_vec_info);
52 static bool vect_analyze_operations (loop_vec_info);
54 /* Utility functions for the analyses. */
55 static bool exist_non_indexing_operands_for_use_p (tree, tree);
56 static void vect_mark_relevant (varray_type *, tree);
57 static bool vect_stmt_relevant_p (tree, loop_vec_info);
58 static tree vect_get_loop_niters (struct loop *, tree *);
59 static bool vect_analyze_data_ref_dependence
60 (struct data_reference *, struct data_reference *, loop_vec_info);
61 static bool vect_compute_data_ref_alignment (struct data_reference *);
62 static bool vect_analyze_data_ref_access (struct data_reference *);
63 static struct data_reference * vect_analyze_pointer_ref_access
64 (tree, tree, bool, tree, tree *, tree *);
65 static bool vect_can_advance_ivs_p (loop_vec_info);
66 static tree vect_get_ptr_offset (tree, tree, tree *);
67 static bool vect_analyze_offset_expr (tree, struct loop *, tree, tree *,
69 static bool vect_base_addr_differ_p (struct data_reference *,
70 struct data_reference *drb, bool *);
71 static tree vect_object_analysis (tree, tree, bool, tree,
72 struct data_reference **, tree *, tree *,
73 tree *, bool *, tree *);
74 static tree vect_address_analysis (tree, tree, bool, tree,
75 struct data_reference *, tree *, tree *,
79 /* Function vect_get_ptr_offset
81 Compute the OFFSET modulo vector-type alignment of pointer REF in bits. */
84 vect_get_ptr_offset (tree ref ATTRIBUTE_UNUSED,
85 tree vectype ATTRIBUTE_UNUSED,
86 tree *offset ATTRIBUTE_UNUSED)
88 /* TODO: Use alignment information. */
93 /* Function vect_analyze_offset_expr
95 Given an offset expression EXPR received from get_inner_reference, analyze
96 it and create an expression for INITIAL_OFFSET by substituting the variables
97 of EXPR with initial_condition of the corresponding access_fn in the loop.
100 for (j = 3; j < N; j++)
103 For a[j].b[i][j], EXPR will be 'i * C_i + j * C_j + C'. 'i' cannot be
104 substituted, since its access_fn in the inner loop is i. 'j' will be
105 substituted with 3. An INITIAL_OFFSET will be 'i * C_i + C`', where
108 Compute MISALIGN (the misalignment of the data reference initial access from
109 its base) if possible. Misalignment can be calculated only if all the
110 variables can be substituted with constants, or if a variable is multiplied
111 by a multiple of VECTYPE_ALIGNMENT. In the above example, since 'i' cannot
112 be substituted, MISALIGN will be NULL_TREE in case that C_i is not a multiple
113 of VECTYPE_ALIGNMENT, and C` otherwise. (We perform MISALIGN modulo
114 VECTYPE_ALIGNMENT computation in the caller of this function).
116 STEP is an evolution of the data reference in this loop in bytes.
117 In the above example, STEP is C_j.
119 Return FALSE, if the analysis fails, e.g., there is no access_fn for a
120 variable. In this case, all the outputs (INITIAL_OFFSET, MISALIGN and STEP)
121 are NULL_TREEs. Otherwise, return TRUE.
126 vect_analyze_offset_expr (tree expr,
128 tree vectype_alignment,
129 tree *initial_offset,
135 tree left_offset = ssize_int (0);
136 tree right_offset = ssize_int (0);
137 tree left_misalign = ssize_int (0);
138 tree right_misalign = ssize_int (0);
139 tree left_step = ssize_int (0);
140 tree right_step = ssize_int (0);
142 tree init, evolution;
145 *misalign = NULL_TREE;
146 *initial_offset = NULL_TREE;
148 /* Strip conversions that don't narrow the mode. */
149 expr = vect_strip_conversion (expr);
155 if (TREE_CODE (expr) == INTEGER_CST)
157 *initial_offset = fold_convert (ssizetype, expr);
158 *misalign = fold_convert (ssizetype, expr);
159 *step = ssize_int (0);
163 /* 2. Variable. Try to substitute with initial_condition of the corresponding
164 access_fn in the current loop. */
165 if (SSA_VAR_P (expr))
167 tree access_fn = analyze_scalar_evolution (loop, expr);
169 if (access_fn == chrec_dont_know)
173 init = initial_condition_in_loop_num (access_fn, loop->num);
174 if (init == expr && !expr_invariant_in_loop_p (loop, init))
175 /* Not enough information: may be not loop invariant.
176 E.g., for a[b[i]], we get a[D], where D=b[i]. EXPR is D, its
177 initial_condition is D, but it depends on i - loop's induction
181 evolution = evolution_part_in_loop_num (access_fn, loop->num);
182 if (evolution && TREE_CODE (evolution) != INTEGER_CST)
183 /* Evolution is not constant. */
186 if (TREE_CODE (init) == INTEGER_CST)
187 *misalign = fold_convert (ssizetype, init);
189 /* Not constant, misalignment cannot be calculated. */
190 *misalign = NULL_TREE;
192 *initial_offset = fold_convert (ssizetype, init);
194 *step = evolution ? fold_convert (ssizetype, evolution) : ssize_int (0);
198 /* Recursive computation. */
199 if (!BINARY_CLASS_P (expr))
201 /* We expect to get binary expressions (PLUS/MINUS and MULT). */
202 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
204 fprintf (vect_dump, "Not binary expression ");
205 print_generic_expr (vect_dump, expr, TDF_SLIM);
209 oprnd0 = TREE_OPERAND (expr, 0);
210 oprnd1 = TREE_OPERAND (expr, 1);
212 if (!vect_analyze_offset_expr (oprnd0, loop, vectype_alignment, &left_offset,
213 &left_misalign, &left_step)
214 || !vect_analyze_offset_expr (oprnd1, loop, vectype_alignment,
215 &right_offset, &right_misalign, &right_step))
218 /* The type of the operation: plus, minus or mult. */
219 code = TREE_CODE (expr);
223 if (TREE_CODE (right_offset) != INTEGER_CST)
224 /* RIGHT_OFFSET can be not constant. For example, for arrays of variable
226 FORNOW: We don't support such cases. */
229 /* Strip conversions that don't narrow the mode. */
230 left_offset = vect_strip_conversion (left_offset);
233 /* Misalignment computation. */
234 if (SSA_VAR_P (left_offset))
236 /* If the left side contains variables that can't be substituted with
237 constants, we check if the right side is a multiple of ALIGNMENT.
239 if (integer_zerop (size_binop (TRUNC_MOD_EXPR, right_offset,
240 fold_convert (ssizetype, vectype_alignment))))
241 *misalign = ssize_int (0);
243 /* If the remainder is not zero or the right side isn't constant,
244 we can't compute misalignment. */
245 *misalign = NULL_TREE;
249 /* The left operand was successfully substituted with constant. */
251 /* In case of EXPR '(i * C1 + j) * C2', LEFT_MISALIGN is
253 *misalign = size_binop (code, left_misalign, right_misalign);
255 *misalign = NULL_TREE;
258 /* Step calculation. */
259 /* Multiply the step by the right operand. */
260 *step = size_binop (MULT_EXPR, left_step, right_offset);
265 /* Combine the recursive calculations for step and misalignment. */
266 *step = size_binop (code, left_step, right_step);
268 if (left_misalign && right_misalign)
269 *misalign = size_binop (code, left_misalign, right_misalign);
271 *misalign = NULL_TREE;
279 /* Compute offset. */
280 *initial_offset = fold_convert (ssizetype,
281 fold (build2 (code, TREE_TYPE (left_offset),
288 /* Function vect_analyze_operations.
290 Scan the loop stmts and make sure they are all vectorizable. */
293 vect_analyze_operations (loop_vec_info loop_vinfo)
295 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
296 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
297 int nbbs = loop->num_nodes;
298 block_stmt_iterator si;
299 unsigned int vectorization_factor = 0;
304 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
305 fprintf (vect_dump, "=== vect_analyze_operations ===");
307 for (i = 0; i < nbbs; i++)
309 basic_block bb = bbs[i];
311 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
313 tree stmt = bsi_stmt (si);
315 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
318 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
320 fprintf (vect_dump, "==> examining statement: ");
321 print_generic_expr (vect_dump, stmt, TDF_SLIM);
324 gcc_assert (stmt_info);
326 /* skip stmts which do not need to be vectorized.
327 this is expected to include:
328 - the COND_EXPR which is the loop exit condition
329 - any LABEL_EXPRs in the loop
330 - computations that are used only for array indexing or loop
333 if (!STMT_VINFO_RELEVANT_P (stmt_info))
335 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
336 fprintf (vect_dump, "irrelevant.");
340 if (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))))
342 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
343 LOOP_LOC (loop_vinfo)))
345 fprintf (vect_dump, "not vectorized: vector stmt in loop:");
346 print_generic_expr (vect_dump, stmt, TDF_SLIM);
351 if (STMT_VINFO_DATA_REF (stmt_info))
352 scalar_type = TREE_TYPE (DR_REF (STMT_VINFO_DATA_REF (stmt_info)));
353 else if (TREE_CODE (stmt) == MODIFY_EXPR)
354 scalar_type = TREE_TYPE (TREE_OPERAND (stmt, 0));
356 scalar_type = TREE_TYPE (stmt);
358 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
360 fprintf (vect_dump, "get vectype for scalar type: ");
361 print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
364 vectype = get_vectype_for_scalar_type (scalar_type);
367 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
368 LOOP_LOC (loop_vinfo)))
371 "not vectorized: unsupported data-type ");
372 print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
377 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
379 fprintf (vect_dump, "vectype: ");
380 print_generic_expr (vect_dump, vectype, TDF_SLIM);
382 STMT_VINFO_VECTYPE (stmt_info) = vectype;
384 ok = (vectorizable_operation (stmt, NULL, NULL)
385 || vectorizable_assignment (stmt, NULL, NULL)
386 || vectorizable_load (stmt, NULL, NULL)
387 || vectorizable_store (stmt, NULL, NULL));
391 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
392 LOOP_LOC (loop_vinfo)))
394 fprintf (vect_dump, "not vectorized: stmt not supported: ");
395 print_generic_expr (vect_dump, stmt, TDF_SLIM);
400 nunits = GET_MODE_NUNITS (TYPE_MODE (vectype));
401 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
402 fprintf (vect_dump, "nunits = %d", nunits);
404 if (vectorization_factor)
406 /* FORNOW: don't allow mixed units.
407 This restriction will be relaxed in the future. */
408 if (nunits != vectorization_factor)
410 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
411 LOOP_LOC (loop_vinfo)))
412 fprintf (vect_dump, "not vectorized: mixed data-types");
417 vectorization_factor = nunits;
419 #ifdef ENABLE_CHECKING
420 gcc_assert (GET_MODE_SIZE (TYPE_MODE (scalar_type))
421 * vectorization_factor == UNITS_PER_SIMD_WORD);
426 /* TODO: Analyze cost. Decide if worth while to vectorize. */
428 if (vectorization_factor <= 1)
430 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
431 LOOP_LOC (loop_vinfo)))
432 fprintf (vect_dump, "not vectorized: unsupported data-type");
435 LOOP_VINFO_VECT_FACTOR (loop_vinfo) = vectorization_factor;
437 if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
438 && vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
440 "vectorization_factor = %d, niters = " HOST_WIDE_INT_PRINT_DEC,
441 vectorization_factor, LOOP_VINFO_INT_NITERS (loop_vinfo));
443 if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
444 && LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor)
446 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
447 LOOP_LOC (loop_vinfo)))
448 fprintf (vect_dump, "not vectorized: iteration count too small.");
452 if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
453 || LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0)
455 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
456 fprintf (vect_dump, "epilog loop required.");
457 if (!vect_can_advance_ivs_p (loop_vinfo))
459 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
460 LOOP_LOC (loop_vinfo)))
462 "not vectorized: can't create epilog loop 1.");
465 if (!slpeel_can_duplicate_loop_p (loop, loop->exit_edges[0]))
467 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
468 LOOP_LOC (loop_vinfo)))
470 "not vectorized: can't create epilog loop 2.");
479 /* Function exist_non_indexing_operands_for_use_p
481 USE is one of the uses attached to STMT. Check if USE is
482 used in STMT for anything other than indexing an array. */
485 exist_non_indexing_operands_for_use_p (tree use, tree stmt)
488 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
490 /* USE corresponds to some operand in STMT. If there is no data
491 reference in STMT, then any operand that corresponds to USE
492 is not indexing an array. */
493 if (!STMT_VINFO_DATA_REF (stmt_info))
496 /* STMT has a data_ref. FORNOW this means that its of one of
500 (This should have been verified in analyze_data_refs).
502 'var' in the second case corresponds to a def, not a use,
503 so USE cannot correspond to any operands that are not used
506 Therefore, all we need to check is if STMT falls into the
507 first case, and whether var corresponds to USE. */
509 if (TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
512 operand = TREE_OPERAND (stmt, 1);
514 if (TREE_CODE (operand) != SSA_NAME)
524 /* Function vect_analyze_scalar_cycles.
526 Examine the cross iteration def-use cycles of scalar variables, by
527 analyzing the loop (scalar) PHIs; verify that the cross iteration def-use
528 cycles that they represent do not impede vectorization.
530 FORNOW: Reduction as in the following loop, is not supported yet:
534 The cross-iteration cycle corresponding to variable 'sum' will be
535 considered too complicated and will impede vectorization.
537 FORNOW: Induction as in the following loop, is not supported yet:
542 However, the following loop *is* vectorizable:
547 In both loops there exists a def-use cycle for the variable i:
548 loop: i_2 = PHI (i_0, i_1)
553 The evolution of the above cycle is considered simple enough,
554 however, we also check that the cycle does not need to be
555 vectorized, i.e - we check that the variable that this cycle
556 defines is only used for array indexing or in stmts that do not
557 need to be vectorized. This is not the case in loop2, but it
558 *is* the case in loop3. */
561 vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
564 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
565 basic_block bb = loop->header;
568 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
569 fprintf (vect_dump, "=== vect_analyze_scalar_cycles ===");
571 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
573 tree access_fn = NULL;
575 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
577 fprintf (vect_dump, "Analyze phi: ");
578 print_generic_expr (vect_dump, phi, TDF_SLIM);
581 /* Skip virtual phi's. The data dependences that are associated with
582 virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
584 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
586 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
587 fprintf (vect_dump, "virtual phi. skip.");
591 /* Analyze the evolution function. */
593 /* FORNOW: The only scalar cross-iteration cycles that we allow are
594 those of loop induction variables; This property is verified here.
596 Furthermore, if that induction variable is used in an operation
597 that needs to be vectorized (i.e, is not solely used to index
598 arrays and check the exit condition) - we do not support its
599 vectorization yet. This property is verified in vect_is_simple_use,
600 during vect_analyze_operations. */
602 access_fn = /* instantiate_parameters
604 analyze_scalar_evolution (loop, PHI_RESULT (phi));
608 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
609 LOOP_LOC (loop_vinfo)))
610 fprintf (vect_dump, "not vectorized: unsupported scalar cycle.");
614 if (vect_print_dump_info (REPORT_DETAILS,
615 LOOP_LOC (loop_vinfo)))
617 fprintf (vect_dump, "Access function of PHI: ");
618 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
621 if (!vect_is_simple_iv_evolution (loop->num, access_fn, &dummy, &dummy))
623 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
624 LOOP_LOC (loop_vinfo)))
625 fprintf (vect_dump, "not vectorized: unsupported scalar cycle.");
634 /* Function vect_base_addr_differ_p.
636 This is the simplest data dependence test: determines whether the
637 data references A and B access the same array/region. Returns
638 false when the property is not computable at compile time.
639 Otherwise return true, and DIFFER_P will record the result. This
640 utility will not be necessary when alias_sets_conflict_p will be
641 less conservative. */
644 vect_base_addr_differ_p (struct data_reference *dra,
645 struct data_reference *drb,
648 tree stmt_a = DR_STMT (dra);
649 stmt_vec_info stmt_info_a = vinfo_for_stmt (stmt_a);
650 tree stmt_b = DR_STMT (drb);
651 stmt_vec_info stmt_info_b = vinfo_for_stmt (stmt_b);
652 tree addr_a = STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info_a);
653 tree addr_b = STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info_b);
654 tree type_a = TREE_TYPE (addr_a);
655 tree type_b = TREE_TYPE (addr_b);
656 HOST_WIDE_INT alias_set_a, alias_set_b;
658 gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b));
660 /* Both references are ADDR_EXPR, i.e., we have the objects. */
661 if (TREE_CODE (addr_a) == ADDR_EXPR && TREE_CODE (addr_b) == ADDR_EXPR)
662 return array_base_name_differ_p (dra, drb, differ_p);
664 alias_set_a = (TREE_CODE (addr_a) == ADDR_EXPR) ?
665 get_alias_set (TREE_OPERAND (addr_a, 0)) : get_alias_set (addr_a);
666 alias_set_b = (TREE_CODE (addr_b) == ADDR_EXPR) ?
667 get_alias_set (TREE_OPERAND (addr_b, 0)) : get_alias_set (addr_b);
669 if (!alias_sets_conflict_p (alias_set_a, alias_set_b))
675 /* An instruction writing through a restricted pointer is "independent" of any
676 instruction reading or writing through a different pointer, in the same
678 else if ((TYPE_RESTRICT (type_a) && !DR_IS_READ (dra))
679 || (TYPE_RESTRICT (type_b) && !DR_IS_READ (drb)))
688 /* Function vect_analyze_data_ref_dependence.
690 Return TRUE if there (might) exist a dependence between a memory-reference
691 DRA and a memory-reference DRB. */
694 vect_analyze_data_ref_dependence (struct data_reference *dra,
695 struct data_reference *drb,
696 loop_vec_info loop_vinfo)
699 struct data_dependence_relation *ddr;
701 if (!vect_base_addr_differ_p (dra, drb, &differ_p))
703 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
704 LOOP_LOC (loop_vinfo)))
707 "not vectorized: can't determine dependence between: ");
708 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
709 fprintf (vect_dump, " and ");
710 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
718 ddr = initialize_data_dependence_relation (dra, drb);
719 compute_affine_dependence (ddr);
721 if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
724 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
725 LOOP_LOC (loop_vinfo)))
728 "not vectorized: possible dependence between data-refs ");
729 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
730 fprintf (vect_dump, " and ");
731 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
738 /* Function vect_analyze_data_ref_dependences.
740 Examine all the data references in the loop, and make sure there do not
741 exist any data dependences between them.
743 TODO: dependences which distance is greater than the vectorization factor
747 vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo)
750 varray_type loop_write_refs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
751 varray_type loop_read_refs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
753 /* Examine store-store (output) dependences. */
755 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
756 fprintf (vect_dump, "=== vect_analyze_dependences ===");
758 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
759 fprintf (vect_dump, "compare all store-store pairs.");
761 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_refs); i++)
763 for (j = i + 1; j < VARRAY_ACTIVE_SIZE (loop_write_refs); j++)
765 struct data_reference *dra =
766 VARRAY_GENERIC_PTR (loop_write_refs, i);
767 struct data_reference *drb =
768 VARRAY_GENERIC_PTR (loop_write_refs, j);
769 if (vect_analyze_data_ref_dependence (dra, drb, loop_vinfo))
774 /* Examine load-store (true/anti) dependences. */
776 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
777 fprintf (vect_dump, "compare all load-store pairs.");
779 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_refs); i++)
781 for (j = 0; j < VARRAY_ACTIVE_SIZE (loop_write_refs); j++)
783 struct data_reference *dra = VARRAY_GENERIC_PTR (loop_read_refs, i);
784 struct data_reference *drb =
785 VARRAY_GENERIC_PTR (loop_write_refs, j);
786 if (vect_analyze_data_ref_dependence (dra, drb, loop_vinfo))
795 /* Function vect_compute_data_ref_alignment
797 Compute the misalignment of the data reference DR.
800 1. If during the misalignment computation it is found that the data reference
801 cannot be vectorized then false is returned.
802 2. DR_MISALIGNMENT (DR) is defined.
804 FOR NOW: No analysis is actually performed. Misalignment is calculated
805 only for trivial cases. TODO. */
808 vect_compute_data_ref_alignment (struct data_reference *dr)
810 tree stmt = DR_STMT (dr);
811 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
812 tree ref = DR_REF (dr);
814 tree base, alignment;
818 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
819 fprintf (vect_dump, "vect_compute_data_ref_alignment:");
821 /* Initialize misalignment to unknown. */
822 DR_MISALIGNMENT (dr) = -1;
824 misalign = STMT_VINFO_VECT_MISALIGNMENT (stmt_info);
825 base_aligned_p = STMT_VINFO_VECT_BASE_ALIGNED_P (stmt_info);
826 base = build_fold_indirect_ref (STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info));
827 vectype = STMT_VINFO_VECTYPE (stmt_info);
831 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
833 fprintf (vect_dump, "Unknown alignment for access: ");
834 print_generic_expr (vect_dump, base, TDF_SLIM);
841 if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype)))
843 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
845 fprintf (vect_dump, "can't force alignment of ref: ");
846 print_generic_expr (vect_dump, ref, TDF_SLIM);
851 /* Force the alignment of the decl.
852 NOTE: This is the only change to the code we make during
853 the analysis phase, before deciding to vectorize the loop. */
854 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
855 fprintf (vect_dump, "force alignment");
856 DECL_ALIGN (base) = TYPE_ALIGN (vectype);
857 DECL_USER_ALIGN (base) = 1;
860 /* At this point we assume that the base is aligned. */
861 gcc_assert (base_aligned_p
862 || (TREE_CODE (base) == VAR_DECL
863 && DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
865 /* Alignment required, in bytes: */
866 alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT);
868 /* Modulo alignment. */
869 misalign = size_binop (TRUNC_MOD_EXPR, misalign, alignment);
870 if (tree_int_cst_sgn (misalign) < 0)
872 /* Negative misalignment value. */
873 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
874 fprintf (vect_dump, "unexpected misalign value");
878 DR_MISALIGNMENT (dr) = tree_low_cst (misalign, 1);
880 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
881 fprintf (vect_dump, "misalign = %d bytes", DR_MISALIGNMENT (dr));
887 /* Function vect_compute_data_refs_alignment
889 Compute the misalignment of data references in the loop.
890 This pass may take place at function granularity instead of at loop
893 FOR NOW: No analysis is actually performed. Misalignment is calculated
894 only for trivial cases. TODO. */
897 vect_compute_data_refs_alignment (loop_vec_info loop_vinfo)
899 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
900 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
903 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
905 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
906 if (!vect_compute_data_ref_alignment (dr))
910 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
912 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
913 if (!vect_compute_data_ref_alignment (dr))
921 /* Function vect_enhance_data_refs_alignment
923 This pass will use loop versioning and loop peeling in order to enhance
924 the alignment of data references in the loop.
926 FOR NOW: we assume that whatever versioning/peeling takes place, only the
927 original loop is to be vectorized; Any other loops that are created by
928 the transformations performed in this pass - are not supposed to be
929 vectorized. This restriction will be relaxed. */
932 vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
934 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
935 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
939 This pass will require a cost model to guide it whether to apply peeling
940 or versioning or a combination of the two. For example, the scheme that
941 intel uses when given a loop with several memory accesses, is as follows:
942 choose one memory access ('p') which alignment you want to force by doing
943 peeling. Then, either (1) generate a loop in which 'p' is aligned and all
944 other accesses are not necessarily aligned, or (2) use loop versioning to
945 generate one loop in which all accesses are aligned, and another loop in
946 which only 'p' is necessarily aligned.
948 ("Automatic Intra-Register Vectorization for the Intel Architecture",
949 Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International
950 Journal of Parallel Programming, Vol. 30, No. 2, April 2002.)
952 Devising a cost model is the most critical aspect of this work. It will
953 guide us on which access to peel for, whether to use loop versioning, how
954 many versions to create, etc. The cost model will probably consist of
955 generic considerations as well as target specific considerations (on
956 powerpc for example, misaligned stores are more painful than misaligned
959 Here is the general steps involved in alignment enhancements:
961 -- original loop, before alignment analysis:
963 x = q[i]; # DR_MISALIGNMENT(q) = unknown
964 p[i] = y; # DR_MISALIGNMENT(p) = unknown
967 -- After vect_compute_data_refs_alignment:
969 x = q[i]; # DR_MISALIGNMENT(q) = 3
970 p[i] = y; # DR_MISALIGNMENT(p) = unknown
973 -- Possibility 1: we do loop versioning:
975 for (i=0; i<N; i++){ # loop 1A
976 x = q[i]; # DR_MISALIGNMENT(q) = 3
977 p[i] = y; # DR_MISALIGNMENT(p) = 0
981 for (i=0; i<N; i++){ # loop 1B
982 x = q[i]; # DR_MISALIGNMENT(q) = 3
983 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
987 -- Possibility 2: we do loop peeling:
988 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
992 for (i = 3; i < N; i++){ # loop 2A
993 x = q[i]; # DR_MISALIGNMENT(q) = 0
994 p[i] = y; # DR_MISALIGNMENT(p) = unknown
997 -- Possibility 3: combination of loop peeling and versioning:
998 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
1003 for (i = 3; i<N; i++){ # loop 3A
1004 x = q[i]; # DR_MISALIGNMENT(q) = 0
1005 p[i] = y; # DR_MISALIGNMENT(p) = 0
1009 for (i = 3; i<N; i++){ # loop 3B
1010 x = q[i]; # DR_MISALIGNMENT(q) = 0
1011 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
1015 These loops are later passed to loop_transform to be vectorized. The
1016 vectorizer will use the alignment information to guide the transformation
1017 (whether to generate regular loads/stores, or with special handling for
1021 /* (1) Peeling to force alignment. */
1023 /* (1.1) Decide whether to perform peeling, and how many iterations to peel:
1025 + How many accesses will become aligned due to the peeling
1026 - How many accesses will become unaligned due to the peeling,
1027 and the cost of misaligned accesses.
1028 - The cost of peeling (the extra runtime checks, the increase
1031 The scheme we use FORNOW: peel to force the alignment of the first
1032 misaligned store in the loop.
1033 Rationale: misaligned stores are not yet supported.
1035 TODO: Use a better cost model. */
1037 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1039 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1040 if (!aligned_access_p (dr))
1042 LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr;
1043 LOOP_DO_PEELING_FOR_ALIGNMENT (loop_vinfo) = true;
1048 if (!LOOP_VINFO_UNALIGNED_DR (loop_vinfo))
1050 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1051 fprintf (vect_dump, "Peeling for alignment will not be applied.");
1055 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1056 fprintf (vect_dump, "Peeling for alignment will be applied.");
1059 /* (1.2) Update the alignment info according to the peeling factor.
1060 If the misalignment of the DR we peel for is M, then the
1061 peeling factor is VF - M, and the misalignment of each access DR_i
1062 in the loop is DR_MISALIGNMENT (DR_i) + VF - M.
1063 If the misalignment of the DR we peel for is unknown, then the
1064 misalignment of each access DR_i in the loop is also unknown.
1066 FORNOW: set the misalignment of the accesses to unknown even
1067 if the peeling factor is known at compile time.
1069 TODO: - if the peeling factor is known at compile time, use that
1070 when updating the misalignment info of the loop DRs.
1071 - consider accesses that are known to have the same
1072 alignment, even if that alignment is unknown. */
1074 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1076 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1077 if (dr == LOOP_VINFO_UNALIGNED_DR (loop_vinfo))
1079 DR_MISALIGNMENT (dr) = 0;
1080 if (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo)))
1081 fprintf (vect_dump, "Alignment of access forced using peeling.");
1084 DR_MISALIGNMENT (dr) = -1;
1086 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1088 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1089 if (dr == LOOP_VINFO_UNALIGNED_DR (loop_vinfo))
1091 DR_MISALIGNMENT (dr) = 0;
1092 if (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo)))
1093 fprintf (vect_dump, "Alignment of access forced using peeling.");
1096 DR_MISALIGNMENT (dr) = -1;
1101 /* Function vect_analyze_data_refs_alignment
1103 Analyze the alignment of the data-references in the loop.
1104 FOR NOW: Until support for misliagned accesses is in place, only if all
1105 accesses are aligned can the loop be vectorized. This restriction will be
1109 vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo)
1111 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1112 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1113 enum dr_alignment_support supportable_dr_alignment;
1116 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1117 fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ===");
1120 /* This pass may take place at function granularity instead of at loop
1123 if (!vect_compute_data_refs_alignment (loop_vinfo))
1125 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1126 LOOP_LOC (loop_vinfo)))
1128 "not vectorized: can't calculate alignment for data ref.");
1133 /* This pass will decide on using loop versioning and/or loop peeling in
1134 order to enhance the alignment of data references in the loop. */
1136 vect_enhance_data_refs_alignment (loop_vinfo);
1139 /* Finally, check that all the data references in the loop can be
1140 handled with respect to their alignment. */
1142 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1144 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1145 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1146 if (!supportable_dr_alignment)
1148 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1149 LOOP_LOC (loop_vinfo)))
1150 fprintf (vect_dump, "not vectorized: unsupported unaligned load.");
1153 if (supportable_dr_alignment != dr_aligned
1154 && (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo))))
1155 fprintf (vect_dump, "Vectorizing an unaligned access.");
1157 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1159 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1160 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1161 if (!supportable_dr_alignment)
1163 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1164 LOOP_LOC (loop_vinfo)))
1165 fprintf (vect_dump, "not vectorized: unsupported unaligned store.");
1168 if (supportable_dr_alignment != dr_aligned
1169 && (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo))))
1170 fprintf (vect_dump, "Vectorizing an unaligned access.");
1177 /* Function vect_analyze_data_ref_access.
1179 Analyze the access pattern of the data-reference DR. For now, a data access
1180 has to consecutive to be considered vectorizable. */
1183 vect_analyze_data_ref_access (struct data_reference *dr)
1185 tree stmt = DR_STMT (dr);
1186 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1187 tree step = STMT_VINFO_VECT_STEP (stmt_info);
1188 tree scalar_type = TREE_TYPE (DR_REF (dr));
1190 if (!step || tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
1192 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1193 fprintf (vect_dump, "not consecutive access");
1200 /* Function vect_analyze_data_ref_accesses.
1202 Analyze the access pattern of all the data references in the loop.
1204 FORNOW: the only access pattern that is considered vectorizable is a
1205 simple step 1 (consecutive) access.
1207 FORNOW: handle only arrays and pointer accesses. */
1210 vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo)
1213 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1214 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1216 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1217 fprintf (vect_dump, "=== vect_analyze_data_ref_accesses ===");
1219 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1221 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1222 bool ok = vect_analyze_data_ref_access (dr);
1225 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1226 LOOP_LOC (loop_vinfo)))
1227 fprintf (vect_dump, "not vectorized: complicated access pattern.");
1232 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1234 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1235 bool ok = vect_analyze_data_ref_access (dr);
1238 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1239 LOOP_LOC (loop_vinfo)))
1240 fprintf (vect_dump, "not vectorized: complicated access pattern.");
1249 /* Function vect_analyze_pointer_ref_access.
1252 STMT - a stmt that contains a data-ref.
1253 MEMREF - a data-ref in STMT, which is an INDIRECT_REF.
1254 ACCESS_FN - the access function of MEMREF.
1257 If the data-ref access is vectorizable, return a data_reference structure
1258 that represents it (DR). Otherwise - return NULL.
1259 STEP - the stride of MEMREF in the loop.
1260 INIT - the initial condition of MEMREF in the loop.
1263 static struct data_reference *
1264 vect_analyze_pointer_ref_access (tree memref, tree stmt, bool is_read,
1265 tree access_fn, tree *ptr_init, tree *ptr_step)
1267 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1268 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1269 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1271 tree reftype, innertype;
1272 tree indx_access_fn;
1273 int loopnum = loop->num;
1274 struct data_reference *dr;
1276 if (!vect_is_simple_iv_evolution (loopnum, access_fn, &init, &step))
1278 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1279 LOOP_LOC (loop_vinfo)))
1280 fprintf (vect_dump, "not vectorized: pointer access is not simple.");
1286 if (!expr_invariant_in_loop_p (loop, init))
1288 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1289 LOOP_LOC (loop_vinfo)))
1291 "not vectorized: initial condition is not loop invariant.");
1295 if (TREE_CODE (step) != INTEGER_CST)
1297 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1298 LOOP_LOC (loop_vinfo)))
1300 "not vectorized: non constant step for pointer access.");
1304 reftype = TREE_TYPE (TREE_OPERAND (memref, 0));
1305 if (!POINTER_TYPE_P (reftype))
1307 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1308 LOOP_LOC (loop_vinfo)))
1309 fprintf (vect_dump, "not vectorized: unexpected pointer access form.");
1313 reftype = TREE_TYPE (init);
1314 if (!POINTER_TYPE_P (reftype))
1316 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1317 LOOP_LOC (loop_vinfo)))
1318 fprintf (vect_dump, "not vectorized: unexpected pointer access form.");
1322 *ptr_step = fold_convert (ssizetype, step);
1323 innertype = TREE_TYPE (reftype);
1324 /* Check that STEP is a multiple of type size. */
1325 if (!integer_zerop (size_binop (TRUNC_MOD_EXPR, *ptr_step,
1326 fold_convert (ssizetype, TYPE_SIZE_UNIT (innertype)))))
1328 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1329 LOOP_LOC (loop_vinfo)))
1330 fprintf (vect_dump, "not vectorized: non consecutive access.");
1335 build_polynomial_chrec (loopnum, integer_zero_node, integer_one_node);
1336 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1338 fprintf (vect_dump, "Access function of ptr indx: ");
1339 print_generic_expr (vect_dump, indx_access_fn, TDF_SLIM);
1341 dr = init_data_ref (stmt, memref, NULL_TREE, indx_access_fn, is_read);
1347 /* Function vect_address_analysis
1349 Return the BASE of the address expression EXPR.
1350 Also compute the INITIAL_OFFSET from BASE, MISALIGN and STEP.
1353 EXPR - the address expression that is being analyzed
1354 STMT - the statement that contains EXPR or its original memory reference
1355 IS_READ - TRUE if STMT reads from EXPR, FALSE if writes to EXPR
1356 VECTYPE - the type that defines the alignment (i.e, we compute
1357 alignment relative to TYPE_ALIGN(VECTYPE))
1358 DR - data_reference struct for the original memory reference
1361 BASE (returned value) - the base of the data reference EXPR.
1362 INITIAL_OFFSET - initial offset of EXPR from BASE (an expression)
1363 MISALIGN - offset of EXPR from BASE in bytes (a constant) or NULL_TREE if the
1364 computation is impossible
1365 STEP - evolution of EXPR in the loop
1366 BASE_ALIGNED - indicates if BASE is aligned
1368 If something unexpected is encountered (an unsupported form of data-ref),
1369 then NULL_TREE is returned.
1373 vect_address_analysis (tree expr, tree stmt, bool is_read, tree vectype,
1374 struct data_reference *dr, tree *offset, tree *misalign,
1375 tree *step, bool *base_aligned)
1377 tree oprnd0, oprnd1, base_address, offset_expr, base_addr0, base_addr1;
1378 tree address_offset = ssize_int (0), address_misalign = ssize_int (0);
1381 switch (TREE_CODE (expr))
1385 /* EXPR is of form {base +/- offset} (or {offset +/- base}). */
1386 oprnd0 = TREE_OPERAND (expr, 0);
1387 oprnd1 = TREE_OPERAND (expr, 1);
1389 STRIP_NOPS (oprnd0);
1390 STRIP_NOPS (oprnd1);
1392 /* Recursively try to find the base of the address contained in EXPR.
1393 For offset, the returned base will be NULL. */
1394 base_addr0 = vect_address_analysis (oprnd0, stmt, is_read, vectype, dr,
1395 &address_offset, &address_misalign, step,
1398 base_addr1 = vect_address_analysis (oprnd1, stmt, is_read, vectype, dr,
1399 &address_offset, &address_misalign, step,
1402 /* We support cases where only one of the operands contains an
1404 if ((base_addr0 && base_addr1) || (!base_addr0 && !base_addr1))
1407 /* To revert STRIP_NOPS. */
1408 oprnd0 = TREE_OPERAND (expr, 0);
1409 oprnd1 = TREE_OPERAND (expr, 1);
1411 offset_expr = base_addr0 ?
1412 fold_convert (ssizetype, oprnd1) : fold_convert (ssizetype, oprnd0);
1414 /* EXPR is of form {base +/- offset} (or {offset +/- base}). If offset is
1415 a number, we can add it to the misalignment value calculated for base,
1416 otherwise, misalignment is NULL. */
1417 if (TREE_CODE (offset_expr) == INTEGER_CST && address_misalign)
1418 *misalign = size_binop (TREE_CODE (expr), address_misalign,
1421 *misalign = NULL_TREE;
1423 /* Combine offset (from EXPR {base + offset}) with the offset calculated
1425 *offset = size_binop (TREE_CODE (expr), address_offset, offset_expr);
1426 return base_addr0 ? base_addr0 : base_addr1;
1429 base_address = vect_object_analysis (TREE_OPERAND (expr, 0), stmt, is_read,
1430 vectype, &dr, offset, misalign, step,
1431 base_aligned, &dummy);
1432 return base_address;
1435 if (!POINTER_TYPE_P (TREE_TYPE (expr)))
1438 if (TYPE_ALIGN (TREE_TYPE (TREE_TYPE (expr))) < TYPE_ALIGN (vectype))
1440 if (vect_get_ptr_offset (expr, vectype, misalign))
1441 *base_aligned = true;
1443 *base_aligned = false;
1447 *base_aligned = true;
1448 *misalign = ssize_int (0);
1450 *offset = ssize_int (0);
1451 *step = ssize_int (0);
1460 /* Function vect_object_analysis
1462 Return the BASE of the data reference MEMREF.
1463 Also compute the INITIAL_OFFSET from BASE, MISALIGN and STEP.
1464 E.g., for EXPR a.b[i] + 4B, BASE is a, and OFFSET is the overall offset
1465 'a.b[i] + 4B' from a (can be an expression), MISALIGN is an OFFSET
1466 instantiated with initial_conditions of access_functions of variables,
1467 modulo alignment, and STEP is the evolution of the DR_REF in this loop.
1469 Function get_inner_reference is used for the above in case of ARRAY_REF and
1472 The structure of the function is as follows:
1474 Case 1. For handled_component_p refs
1475 1.1 call get_inner_reference
1476 1.1.1 analyze offset expr received from get_inner_reference
1477 1.2. build data-reference structure for MEMREF
1478 (fall through with BASE)
1479 Case 2. For declarations
1481 2.2 update DR_BASE_NAME if necessary for alias
1482 Case 3. For INDIRECT_REFs
1483 3.1 get the access function
1484 3.2 analyze evolution of MEMREF
1485 3.3 set data-reference structure for MEMREF
1486 3.4 call vect_address_analysis to analyze INIT of the access function
1489 Combine the results of object and address analysis to calculate
1490 INITIAL_OFFSET, STEP and misalignment info.
1493 MEMREF - the memory reference that is being analyzed
1494 STMT - the statement that contains MEMREF
1495 IS_READ - TRUE if STMT reads from MEMREF, FALSE if writes to MEMREF
1496 VECTYPE - the type that defines the alignment (i.e, we compute
1497 alignment relative to TYPE_ALIGN(VECTYPE))
1500 BASE_ADDRESS (returned value) - the base address of the data reference MEMREF
1501 E.g, if MEMREF is a.b[k].c[i][j] the returned
1503 DR - data_reference struct for MEMREF
1504 INITIAL_OFFSET - initial offset of MEMREF from BASE (an expression)
1505 MISALIGN - offset of MEMREF from BASE in bytes (a constant) or NULL_TREE if
1506 the computation is impossible
1507 STEP - evolution of the DR_REF in the loop
1508 BASE_ALIGNED - indicates if BASE is aligned
1509 MEMTAG - memory tag for aliasing purposes
1511 If something unexpected is encountered (an unsupported form of data-ref),
1512 then NULL_TREE is returned. */
1515 vect_object_analysis (tree memref, tree stmt, bool is_read,
1516 tree vectype, struct data_reference **dr,
1517 tree *offset, tree *misalign, tree *step,
1518 bool *base_aligned, tree *memtag)
1520 tree base = NULL_TREE, base_address = NULL_TREE;
1521 tree object_offset = ssize_int (0), object_misalign = ssize_int (0);
1522 tree object_step = ssize_int (0), address_step = ssize_int (0);
1523 bool object_base_aligned = true, address_base_aligned = true;
1524 tree address_offset = ssize_int (0), address_misalign = ssize_int (0);
1525 HOST_WIDE_INT pbitsize, pbitpos;
1526 tree poffset, bit_pos_in_bytes;
1527 enum machine_mode pmode;
1528 int punsignedp, pvolatilep;
1529 tree ptr_step = ssize_int (0), ptr_init = NULL_TREE;
1530 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1531 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1532 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1533 struct data_reference *ptr_dr = NULL;
1534 tree access_fn, evolution_part, address_to_analyze;
1537 /* Case 1. handled_component_p refs. */
1538 if (handled_component_p (memref))
1540 /* 1.1 call get_inner_reference. */
1541 /* Find the base and the offset from it. */
1542 base = get_inner_reference (memref, &pbitsize, &pbitpos, &poffset,
1543 &pmode, &punsignedp, &pvolatilep, false);
1547 /* 1.1.1 analyze offset expr received from get_inner_reference. */
1549 && !vect_analyze_offset_expr (poffset, loop, TYPE_SIZE_UNIT (vectype),
1550 &object_offset, &object_misalign, &object_step))
1552 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1554 fprintf (vect_dump, "failed to compute offset or step for ");
1555 print_generic_expr (vect_dump, memref, TDF_SLIM);
1560 /* Add bit position to OFFSET and MISALIGN. */
1562 bit_pos_in_bytes = ssize_int (pbitpos/BITS_PER_UNIT);
1563 /* Check that there is no remainder in bits. */
1564 if (pbitpos%BITS_PER_UNIT)
1566 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1567 fprintf (vect_dump, "bit offset alignment.");
1570 object_offset = size_binop (PLUS_EXPR, bit_pos_in_bytes, object_offset);
1571 if (object_misalign)
1572 object_misalign = size_binop (PLUS_EXPR, object_misalign,
1575 /* Create data-reference for MEMREF. TODO: handle COMPONENT_REFs. */
1578 if (TREE_CODE (memref) == ARRAY_REF)
1579 *dr = analyze_array (stmt, memref, is_read);
1584 memref = base; /* To continue analysis of BASE. */
1588 /* Part 1: Case 2. Declarations. */
1589 if (DECL_P (memref))
1591 /* We expect to get a decl only if we already have a DR. */
1594 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1596 fprintf (vect_dump, "unhandled decl ");
1597 print_generic_expr (vect_dump, memref, TDF_SLIM);
1602 /* 2.1 check the alignment. */
1603 if (DECL_ALIGN (memref) >= TYPE_ALIGN (vectype))
1604 object_base_aligned = true;
1606 object_base_aligned = false;
1608 /* 2.2 update DR_BASE_NAME if necessary. */
1609 if (!DR_BASE_NAME ((*dr)))
1610 /* For alias analysis. In case the analysis of INDIRECT_REF brought
1612 DR_BASE_NAME ((*dr)) = memref;
1614 base_address = build_fold_addr_expr (memref);
1618 /* Part 1: Case 3. INDIRECT_REFs. */
1619 else if (TREE_CODE (memref) == INDIRECT_REF)
1621 /* 3.1 get the access function. */
1622 access_fn = analyze_scalar_evolution (loop, TREE_OPERAND (memref, 0));
1625 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1626 LOOP_LOC (loop_vinfo)))
1627 fprintf (vect_dump, "not vectorized: complicated pointer access.");
1630 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1632 fprintf (vect_dump, "Access function of ptr: ");
1633 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
1636 /* 3.2 analyze evolution of MEMREF. */
1637 evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
1640 ptr_dr = vect_analyze_pointer_ref_access (memref, stmt, is_read,
1641 access_fn, &ptr_init, &ptr_step);
1645 object_step = size_binop (PLUS_EXPR, object_step, ptr_step);
1646 address_to_analyze = ptr_init;
1652 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1653 LOOP_LOC (loop_vinfo)))
1654 fprintf (vect_dump, "not vectorized: ptr is loop invariant.");
1657 /* Since there exists DR for MEMREF, we are analyzing the base of
1658 handled component, which not necessary has evolution in the
1660 address_to_analyze = TREE_OPERAND (base, 0);
1663 /* 3.3 set data-reference structure for MEMREF. */
1664 *dr = (*dr) ? *dr : ptr_dr;
1666 /* 3.4 call vect_address_analysis to analyze INIT of the access
1668 base_address = vect_address_analysis (address_to_analyze, stmt, is_read,
1669 vectype, *dr, &address_offset, &address_misalign,
1670 &address_step, &address_base_aligned);
1674 switch (TREE_CODE (base_address))
1677 *memtag = get_var_ann (SSA_NAME_VAR (base_address))->type_mem_tag;
1678 if (!(*memtag) && TREE_CODE (TREE_OPERAND (memref, 0)) == SSA_NAME)
1679 *memtag = get_var_ann (
1680 SSA_NAME_VAR (TREE_OPERAND (memref, 0)))->type_mem_tag;
1683 *memtag = TREE_OPERAND (base_address, 0);
1686 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1687 LOOP_LOC (loop_vinfo)))
1689 fprintf (vect_dump, "not vectorized: no memtag ref: ");
1690 print_generic_expr (vect_dump, memref, TDF_SLIM);
1697 /* MEMREF cannot be analyzed. */
1700 /* Part 2: Combine the results of object and address analysis to calculate
1701 INITIAL_OFFSET, STEP and misalignment info. */
1702 *offset = size_binop (PLUS_EXPR, object_offset, address_offset);
1703 if (object_misalign && address_misalign)
1704 *misalign = size_binop (PLUS_EXPR, object_misalign, address_misalign);
1706 *misalign = NULL_TREE;
1707 *step = size_binop (PLUS_EXPR, object_step, address_step);
1708 *base_aligned = object_base_aligned && address_base_aligned;
1710 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1712 fprintf (vect_dump, "Results of object analysis for: ");
1713 print_generic_expr (vect_dump, memref, TDF_SLIM);
1714 fprintf (vect_dump, "\n\tbase_address: ");
1715 print_generic_expr (vect_dump, base_address, TDF_SLIM);
1716 fprintf (vect_dump, "\n\toffset: ");
1717 print_generic_expr (vect_dump, *offset, TDF_SLIM);
1718 fprintf (vect_dump, "\n\tstep: ");
1719 print_generic_expr (vect_dump, *step, TDF_SLIM);
1720 fprintf (vect_dump, "\n\tbase aligned %d\n\tmisalign: ", *base_aligned);
1721 print_generic_expr (vect_dump, *misalign, TDF_SLIM);
1723 return base_address;
1727 /* Function vect_analyze_data_refs.
1729 Find all the data references in the loop.
1731 The general structure of the analysis of data refs in the vectorizer is as
1733 1- vect_analyze_data_refs(loop):
1734 Find and analyze all data-refs in the loop:
1736 base_address = vect_object_analysis(ref)
1737 1.1- vect_object_analysis(ref):
1738 Analyze ref, and build a DR (data_referece struct) for it;
1739 compute base, initial_offset, step and alignment.
1740 Call get_inner_reference for refs handled in this function.
1741 Call vect_addr_analysis(addr) to analyze pointer type expressions.
1742 Set ref_stmt.base, ref_stmt.initial_offset, ref_stmt.alignment,
1743 ref_stmt.memtag and ref_stmt.step accordingly.
1744 2- vect_analyze_dependences(): apply dependence testing using ref_stmt.DR
1745 3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok.
1746 4- vect_analyze_drs_access(): check that ref_stmt.step is ok.
1748 FORNOW: Handle aligned INDIRECT_REFs and ARRAY_REFs
1749 which base is really an array (not a pointer) and which alignment
1750 can be forced. This restriction will be relaxed. */
1753 vect_analyze_data_refs (loop_vec_info loop_vinfo)
1755 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1756 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
1757 int nbbs = loop->num_nodes;
1758 block_stmt_iterator si;
1760 struct data_reference *dr;
1762 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1763 fprintf (vect_dump, "=== vect_analyze_data_refs ===");
1765 for (j = 0; j < nbbs; j++)
1767 basic_block bb = bbs[j];
1768 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
1770 bool is_read = false;
1771 tree stmt = bsi_stmt (si);
1772 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1773 v_may_def_optype v_may_defs = STMT_V_MAY_DEF_OPS (stmt);
1774 v_must_def_optype v_must_defs = STMT_V_MUST_DEF_OPS (stmt);
1775 vuse_optype vuses = STMT_VUSE_OPS (stmt);
1776 varray_type *datarefs = NULL;
1777 int nvuses, nv_may_defs, nv_must_defs;
1779 tree scalar_type, vectype;
1780 tree base, offset, misalign, step, tag;
1783 /* Assumption: there exists a data-ref in stmt, if and only if
1784 it has vuses/vdefs. */
1786 if (!vuses && !v_may_defs && !v_must_defs)
1789 nvuses = NUM_VUSES (vuses);
1790 nv_may_defs = NUM_V_MAY_DEFS (v_may_defs);
1791 nv_must_defs = NUM_V_MUST_DEFS (v_must_defs);
1793 if (nvuses && (nv_may_defs || nv_must_defs))
1795 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1797 fprintf (vect_dump, "unexpected vdefs and vuses in stmt: ");
1798 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1803 if (TREE_CODE (stmt) != MODIFY_EXPR)
1805 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1807 fprintf (vect_dump, "unexpected vops in stmt: ");
1808 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1815 memref = TREE_OPERAND (stmt, 1);
1816 datarefs = &(LOOP_VINFO_DATAREF_READS (loop_vinfo));
1821 memref = TREE_OPERAND (stmt, 0);
1822 datarefs = &(LOOP_VINFO_DATAREF_WRITES (loop_vinfo));
1826 scalar_type = TREE_TYPE (memref);
1827 vectype = get_vectype_for_scalar_type (scalar_type);
1830 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1832 fprintf (vect_dump, "no vectype for stmt: ");
1833 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1834 fprintf (vect_dump, " scalar_type: ");
1835 print_generic_expr (vect_dump, scalar_type, TDF_DETAILS);
1837 /* It is not possible to vectorize this data reference. */
1840 /* Analyze MEMREF. If it is of a supported form, build data_reference
1841 struct for it (DR). */
1843 base = vect_object_analysis (memref, stmt, is_read, vectype, &dr,
1844 &offset, &misalign, &step,
1845 &base_aligned, &tag);
1848 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1849 LOOP_LOC (loop_vinfo)))
1851 fprintf (vect_dump, "not vectorized: unhandled data ref: ");
1852 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1856 STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info) = base;
1857 STMT_VINFO_VECT_INIT_OFFSET (stmt_info) = offset;
1858 STMT_VINFO_VECT_STEP (stmt_info) = step;
1859 STMT_VINFO_VECT_MISALIGNMENT (stmt_info) = misalign;
1860 STMT_VINFO_VECT_BASE_ALIGNED_P (stmt_info) = base_aligned;
1861 STMT_VINFO_MEMTAG (stmt_info) = tag;
1862 STMT_VINFO_VECTYPE (stmt_info) = vectype;
1863 VARRAY_PUSH_GENERIC_PTR (*datarefs, dr);
1864 STMT_VINFO_DATA_REF (stmt_info) = dr;
1872 /* Utility functions used by vect_mark_stmts_to_be_vectorized. */
1874 /* Function vect_mark_relevant.
1876 Mark STMT as "relevant for vectorization" and add it to WORKLIST. */
1879 vect_mark_relevant (varray_type *worklist, tree stmt)
1881 stmt_vec_info stmt_info;
1883 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1884 fprintf (vect_dump, "mark relevant.");
1886 if (TREE_CODE (stmt) == PHI_NODE)
1888 VARRAY_PUSH_TREE (*worklist, stmt);
1892 stmt_info = vinfo_for_stmt (stmt);
1896 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1898 fprintf (vect_dump, "mark relevant: no stmt info!!.");
1899 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1904 if (STMT_VINFO_RELEVANT_P (stmt_info))
1906 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1907 fprintf (vect_dump, "already marked relevant.");
1911 STMT_VINFO_RELEVANT_P (stmt_info) = 1;
1912 VARRAY_PUSH_TREE (*worklist, stmt);
1916 /* Function vect_stmt_relevant_p.
1918 Return true if STMT in loop that is represented by LOOP_VINFO is
1919 "relevant for vectorization".
1921 A stmt is considered "relevant for vectorization" if:
1922 - it has uses outside the loop.
1923 - it has vdefs (it alters memory).
1924 - control stmts in the loop (except for the exit condition).
1926 CHECKME: what other side effects would the vectorizer allow? */
1929 vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo)
1931 v_may_def_optype v_may_defs;
1932 v_must_def_optype v_must_defs;
1933 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1938 /* cond stmt other than loop exit cond. */
1939 if (is_ctrl_stmt (stmt) && (stmt != LOOP_VINFO_EXIT_COND (loop_vinfo)))
1942 /* changing memory. */
1943 if (TREE_CODE (stmt) != PHI_NODE)
1945 v_may_defs = STMT_V_MAY_DEF_OPS (stmt);
1946 v_must_defs = STMT_V_MUST_DEF_OPS (stmt);
1947 if (v_may_defs || v_must_defs)
1949 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1950 fprintf (vect_dump, "vec_stmt_relevant_p: stmt has vdefs.");
1955 /* uses outside the loop. */
1956 df = get_immediate_uses (stmt);
1957 num_uses = num_immediate_uses (df);
1958 for (i = 0; i < num_uses; i++)
1960 tree use = immediate_use (df, i);
1961 basic_block bb = bb_for_stmt (use);
1962 if (!flow_bb_inside_loop_p (loop, bb))
1964 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1965 fprintf (vect_dump, "vec_stmt_relevant_p: used out of loop.");
1974 /* Function vect_mark_stmts_to_be_vectorized.
1976 Not all stmts in the loop need to be vectorized. For example:
1985 Stmt 1 and 3 do not need to be vectorized, because loop control and
1986 addressing of vectorized data-refs are handled differently.
1988 This pass detects such stmts. */
1991 vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo)
1993 varray_type worklist;
1994 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1995 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
1996 unsigned int nbbs = loop->num_nodes;
1997 block_stmt_iterator si;
2003 stmt_vec_info stmt_info;
2007 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2008 fprintf (vect_dump, "=== vect_mark_stmts_to_be_vectorized ===");
2011 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
2013 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2015 fprintf (vect_dump, "init: phi relevant? ");
2016 print_generic_expr (vect_dump, phi, TDF_SLIM);
2019 if (vect_stmt_relevant_p (phi, loop_vinfo))
2021 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2022 LOOP_LOC (loop_vinfo)))
2023 fprintf (vect_dump, "unsupported reduction/induction.");
2028 VARRAY_TREE_INIT (worklist, 64, "work list");
2030 /* 1. Init worklist. */
2032 for (i = 0; i < nbbs; i++)
2035 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
2037 stmt = bsi_stmt (si);
2039 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2041 fprintf (vect_dump, "init: stmt relevant? ");
2042 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2045 stmt_info = vinfo_for_stmt (stmt);
2046 STMT_VINFO_RELEVANT_P (stmt_info) = 0;
2048 if (vect_stmt_relevant_p (stmt, loop_vinfo))
2049 vect_mark_relevant (&worklist, stmt);
2054 /* 2. Process_worklist */
2056 while (VARRAY_ACTIVE_SIZE (worklist) > 0)
2058 stmt = VARRAY_TOP_TREE (worklist);
2059 VARRAY_POP (worklist);
2061 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2063 fprintf (vect_dump, "worklist: examine stmt: ");
2064 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2067 /* Examine the USES in this statement. Mark all the statements which
2068 feed this statement's uses as "relevant", unless the USE is used as
2071 if (TREE_CODE (stmt) == PHI_NODE)
2073 /* follow the def-use chain inside the loop. */
2074 for (j = 0; j < PHI_NUM_ARGS (stmt); j++)
2076 tree arg = PHI_ARG_DEF (stmt, j);
2077 tree def_stmt = NULL_TREE;
2079 if (!vect_is_simple_use (arg, loop_vinfo, &def_stmt))
2081 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2082 LOOP_LOC (loop_vinfo)))
2083 fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
2084 varray_clear (worklist);
2090 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2092 fprintf (vect_dump, "worklist: def_stmt: ");
2093 print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
2096 bb = bb_for_stmt (def_stmt);
2097 if (flow_bb_inside_loop_p (loop, bb))
2098 vect_mark_relevant (&worklist, def_stmt);
2102 ann = stmt_ann (stmt);
2103 use_ops = USE_OPS (ann);
2105 for (i = 0; i < NUM_USES (use_ops); i++)
2107 tree use = USE_OP (use_ops, i);
2109 /* We are only interested in uses that need to be vectorized. Uses
2110 that are used for address computation are not considered relevant.
2112 if (exist_non_indexing_operands_for_use_p (use, stmt))
2114 tree def_stmt = NULL_TREE;
2116 if (!vect_is_simple_use (use, loop_vinfo, &def_stmt))
2118 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2119 LOOP_LOC (loop_vinfo)))
2120 fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
2121 varray_clear (worklist);
2128 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2130 fprintf (vect_dump, "worklist: examine use %d: ", i);
2131 print_generic_expr (vect_dump, use, TDF_SLIM);
2134 bb = bb_for_stmt (def_stmt);
2135 if (flow_bb_inside_loop_p (loop, bb))
2136 vect_mark_relevant (&worklist, def_stmt);
2139 } /* while worklist */
2141 varray_clear (worklist);
2146 /* Function vect_can_advance_ivs_p
2148 In case the number of iterations that LOOP iterates in unknown at compile
2149 time, an epilog loop will be generated, and the loop induction variables
2150 (IVs) will be "advanced" to the value they are supposed to take just before
2151 the epilog loop. Here we check that the access function of the loop IVs
2152 and the expression that represents the loop bound are simple enough.
2153 These restrictions will be relaxed in the future. */
2156 vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
2158 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2159 basic_block bb = loop->header;
2162 /* Analyze phi functions of the loop header. */
2164 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
2166 tree access_fn = NULL;
2167 tree evolution_part;
2169 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2171 fprintf (vect_dump, "Analyze phi: ");
2172 print_generic_expr (vect_dump, phi, TDF_SLIM);
2175 /* Skip virtual phi's. The data dependences that are associated with
2176 virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
2178 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
2180 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2181 fprintf (vect_dump, "virtual phi. skip.");
2185 /* Analyze the evolution function. */
2187 access_fn = instantiate_parameters
2188 (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi)));
2192 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2193 fprintf (vect_dump, "No Access function.");
2197 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2199 fprintf (vect_dump, "Access function of PHI: ");
2200 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
2203 evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
2205 if (evolution_part == NULL_TREE)
2208 /* FORNOW: We do not transform initial conditions of IVs
2209 which evolution functions are a polynomial of degree >= 2. */
2211 if (tree_is_chrec (evolution_part))
2219 /* Function vect_get_loop_niters.
2221 Determine how many iterations the loop is executed.
2222 If an expression that represents the number of iterations
2223 can be constructed, place it in NUMBER_OF_ITERATIONS.
2224 Return the loop exit condition. */
2227 vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
2231 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2232 fprintf (vect_dump, "=== get_loop_niters ===");
2234 niters = number_of_iterations_in_loop (loop);
2236 if (niters != NULL_TREE
2237 && niters != chrec_dont_know)
2239 *number_of_iterations = niters;
2241 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2243 fprintf (vect_dump, "==> get_loop_niters:" );
2244 print_generic_expr (vect_dump, *number_of_iterations, TDF_SLIM);
2248 return get_loop_exit_condition (loop);
2252 /* Function vect_analyze_loop_form.
2254 Verify the following restrictions (some may be relaxed in the future):
2255 - it's an inner-most loop
2256 - number of BBs = 2 (which are the loop header and the latch)
2257 - the loop has a pre-header
2258 - the loop has a single entry and exit
2259 - the loop exit condition is simple enough, and the number of iterations
2260 can be analyzed (a countable loop). */
2262 static loop_vec_info
2263 vect_analyze_loop_form (struct loop *loop)
2265 loop_vec_info loop_vinfo;
2267 tree number_of_iterations = NULL;
2268 bool rescan = false;
2271 loop_loc = find_loop_location (loop);
2273 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2274 fprintf (vect_dump, "=== vect_analyze_loop_form ===");
2278 if (vect_print_dump_info (REPORT_OUTER_LOOPS, loop_loc))
2279 fprintf (vect_dump, "not vectorized: nested loop.");
2283 if (!loop->single_exit
2284 || loop->num_nodes != 2
2285 || EDGE_COUNT (loop->header->preds) != 2
2286 || loop->num_entries != 1)
2288 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2290 if (!loop->single_exit)
2291 fprintf (vect_dump, "not vectorized: multiple exits.");
2292 else if (loop->num_nodes != 2)
2293 fprintf (vect_dump, "not vectorized: too many BBs in loop.");
2294 else if (EDGE_COUNT (loop->header->preds) != 2)
2295 fprintf (vect_dump, "not vectorized: too many incoming edges.");
2296 else if (loop->num_entries != 1)
2297 fprintf (vect_dump, "not vectorized: too many entries.");
2303 /* We assume that the loop exit condition is at the end of the loop. i.e,
2304 that the loop is represented as a do-while (with a proper if-guard
2305 before the loop if needed), where the loop header contains all the
2306 executable statements, and the latch is empty. */
2307 if (!empty_block_p (loop->latch))
2309 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2310 fprintf (vect_dump, "not vectorized: unexpectd loop form.");
2314 /* Make sure we have a preheader basic block. */
2315 if (!loop->pre_header || EDGE_COUNT (loop->pre_header->succs) != 1)
2317 edge e = loop_preheader_edge (loop);
2318 loop_split_edge_with (e, NULL);
2319 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2320 fprintf (vect_dump, "split preheader edge.");
2324 /* Make sure there exists a single-predecessor exit bb: */
2325 if (EDGE_COUNT (loop->single_exit->dest->preds) != 1)
2327 edge e = loop->single_exit;
2328 if (!(e->flags & EDGE_ABNORMAL))
2330 loop_split_edge_with (e, NULL);
2331 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2332 fprintf (vect_dump, "split exit edge.");
2337 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2338 fprintf (vect_dump, "not vectorized: abnormal loop exit edge.");
2345 flow_loop_scan (loop, LOOP_ALL);
2346 /* Flow loop scan does not update loop->single_exit field. */
2347 loop->single_exit = loop->exit_edges[0];
2350 if (empty_block_p (loop->header))
2352 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2353 fprintf (vect_dump, "not vectorized: empty loop.");
2357 loop_cond = vect_get_loop_niters (loop, &number_of_iterations);
2360 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2361 fprintf (vect_dump, "not vectorized: complicated exit condition.");
2365 if (!number_of_iterations)
2367 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2369 "not vectorized: number of iterations cannot be computed.");
2373 if (chrec_contains_undetermined (number_of_iterations))
2375 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2376 fprintf (vect_dump, "Infinite number of iterations.");
2380 loop_vinfo = new_loop_vec_info (loop);
2381 LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
2383 if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
2385 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2387 fprintf (vect_dump, "Symbolic number of iterations is ");
2388 print_generic_expr (vect_dump, number_of_iterations, TDF_DETAILS);
2392 if (LOOP_VINFO_INT_NITERS (loop_vinfo) == 0)
2394 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS, loop_loc))
2395 fprintf (vect_dump, "not vectorized: number of iterations = 0.");
2399 LOOP_VINFO_EXIT_COND (loop_vinfo) = loop_cond;
2400 LOOP_VINFO_LOC (loop_vinfo) = loop_loc;
2406 /* Function vect_analyze_loop.
2408 Apply a set of analyses on LOOP, and create a loop_vec_info struct
2409 for it. The different analyses will record information in the
2410 loop_vec_info struct. */
2412 vect_analyze_loop (struct loop *loop)
2415 loop_vec_info loop_vinfo;
2417 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2418 fprintf (vect_dump, "===== analyze_loop_nest =====");
2420 /* Check the CFG characteristics of the loop (nesting, entry/exit, etc. */
2422 loop_vinfo = vect_analyze_loop_form (loop);
2425 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2426 fprintf (vect_dump, "bad loop form.");
2430 /* Find all data references in the loop (which correspond to vdefs/vuses)
2431 and analyze their evolution in the loop.
2433 FORNOW: Handle only simple, array references, which
2434 alignment can be forced, and aligned pointer-references. */
2436 ok = vect_analyze_data_refs (loop_vinfo);
2439 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2440 fprintf (vect_dump, "bad data references.");
2441 destroy_loop_vec_info (loop_vinfo);
2445 /* Data-flow analysis to detect stmts that do not need to be vectorized. */
2447 ok = vect_mark_stmts_to_be_vectorized (loop_vinfo);
2450 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2451 fprintf (vect_dump, "unexpected pattern.");
2452 destroy_loop_vec_info (loop_vinfo);
2456 /* Check that all cross-iteration scalar data-flow cycles are OK.
2457 Cross-iteration cycles caused by virtual phis are analyzed separately. */
2459 ok = vect_analyze_scalar_cycles (loop_vinfo);
2462 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2463 fprintf (vect_dump, "bad scalar cycle.");
2464 destroy_loop_vec_info (loop_vinfo);
2468 /* Analyze data dependences between the data-refs in the loop.
2469 FORNOW: fail at the first data dependence that we encounter. */
2471 ok = vect_analyze_data_ref_dependences (loop_vinfo);
2474 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2475 fprintf (vect_dump, "bad data dependence.");
2476 destroy_loop_vec_info (loop_vinfo);
2480 /* Analyze the access patterns of the data-refs in the loop (consecutive,
2481 complex, etc.). FORNOW: Only handle consecutive access pattern. */
2483 ok = vect_analyze_data_ref_accesses (loop_vinfo);
2486 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2487 fprintf (vect_dump, "bad data access.");
2488 destroy_loop_vec_info (loop_vinfo);
2492 /* Analyze the alignment of the data-refs in the loop.
2493 FORNOW: Only aligned accesses are handled. */
2495 ok = vect_analyze_data_refs_alignment (loop_vinfo);
2498 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2499 fprintf (vect_dump, "bad data alignment.");
2500 destroy_loop_vec_info (loop_vinfo);
2504 /* Scan all the operations in the loop and make sure they are
2507 ok = vect_analyze_operations (loop_vinfo);
2510 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2511 fprintf (vect_dump, "bad operation or unsupported loop bound.");
2512 destroy_loop_vec_info (loop_vinfo);
2516 LOOP_VINFO_VECTORIZABLE_P (loop_vinfo) = 1;