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);
53 static bool vect_determine_vectorization_factor (loop_vec_info);
55 /* Utility functions for the analyses. */
56 static bool exist_non_indexing_operands_for_use_p (tree, tree);
57 static void vect_mark_relevant (VEC(tree,heap) **, tree);
58 static bool vect_stmt_relevant_p (tree, loop_vec_info);
59 static tree vect_get_loop_niters (struct loop *, tree *);
60 static bool vect_analyze_data_ref_dependence
61 (struct data_reference *, struct data_reference *, loop_vec_info);
62 static bool vect_compute_data_ref_alignment (struct data_reference *);
63 static bool vect_analyze_data_ref_access (struct data_reference *);
64 static struct data_reference * vect_analyze_pointer_ref_access
65 (tree, tree, bool, tree, tree *, tree *);
66 static bool vect_can_advance_ivs_p (loop_vec_info);
67 static tree vect_get_ptr_offset (tree, tree, tree *);
68 static bool vect_analyze_offset_expr (tree, struct loop *, tree, tree *,
70 static bool vect_base_addr_differ_p (struct data_reference *,
71 struct data_reference *drb, bool *);
72 static tree vect_object_analysis (tree, tree, bool, tree,
73 struct data_reference **, tree *, tree *,
74 tree *, bool *, tree *, struct ptr_info_def **,
76 static tree vect_address_analysis (tree, tree, bool, tree,
77 struct data_reference *, tree *, tree *,
81 /* Function vect_get_ptr_offset
83 Compute the OFFSET modulo vector-type alignment of pointer REF in bits. */
86 vect_get_ptr_offset (tree ref ATTRIBUTE_UNUSED,
87 tree vectype ATTRIBUTE_UNUSED,
88 tree *offset ATTRIBUTE_UNUSED)
90 /* TODO: Use alignment information. */
95 /* Function vect_analyze_offset_expr
97 Given an offset expression EXPR received from get_inner_reference, analyze
98 it and create an expression for INITIAL_OFFSET by substituting the variables
99 of EXPR with initial_condition of the corresponding access_fn in the loop.
102 for (j = 3; j < N; j++)
105 For a[j].b[i][j], EXPR will be 'i * C_i + j * C_j + C'. 'i' cannot be
106 substituted, since its access_fn in the inner loop is i. 'j' will be
107 substituted with 3. An INITIAL_OFFSET will be 'i * C_i + C`', where
110 Compute MISALIGN (the misalignment of the data reference initial access from
111 its base) if possible. Misalignment can be calculated only if all the
112 variables can be substituted with constants, or if a variable is multiplied
113 by a multiple of VECTYPE_ALIGNMENT. In the above example, since 'i' cannot
114 be substituted, MISALIGN will be NULL_TREE in case that C_i is not a multiple
115 of VECTYPE_ALIGNMENT, and C` otherwise. (We perform MISALIGN modulo
116 VECTYPE_ALIGNMENT computation in the caller of this function).
118 STEP is an evolution of the data reference in this loop in bytes.
119 In the above example, STEP is C_j.
121 Return FALSE, if the analysis fails, e.g., there is no access_fn for a
122 variable. In this case, all the outputs (INITIAL_OFFSET, MISALIGN and STEP)
123 are NULL_TREEs. Otherwise, return TRUE.
128 vect_analyze_offset_expr (tree expr,
130 tree vectype_alignment,
131 tree *initial_offset,
137 tree left_offset = ssize_int (0);
138 tree right_offset = ssize_int (0);
139 tree left_misalign = ssize_int (0);
140 tree right_misalign = ssize_int (0);
141 tree left_step = ssize_int (0);
142 tree right_step = ssize_int (0);
144 tree init, evolution;
147 *misalign = NULL_TREE;
148 *initial_offset = NULL_TREE;
150 /* Strip conversions that don't narrow the mode. */
151 expr = vect_strip_conversion (expr);
157 if (TREE_CODE (expr) == INTEGER_CST)
159 *initial_offset = fold_convert (ssizetype, expr);
160 *misalign = fold_convert (ssizetype, expr);
161 *step = ssize_int (0);
165 /* 2. Variable. Try to substitute with initial_condition of the corresponding
166 access_fn in the current loop. */
167 if (SSA_VAR_P (expr))
169 tree access_fn = analyze_scalar_evolution (loop, expr);
171 if (access_fn == chrec_dont_know)
175 init = initial_condition_in_loop_num (access_fn, loop->num);
176 if (init == expr && !expr_invariant_in_loop_p (loop, init))
177 /* Not enough information: may be not loop invariant.
178 E.g., for a[b[i]], we get a[D], where D=b[i]. EXPR is D, its
179 initial_condition is D, but it depends on i - loop's induction
183 evolution = evolution_part_in_loop_num (access_fn, loop->num);
184 if (evolution && TREE_CODE (evolution) != INTEGER_CST)
185 /* Evolution is not constant. */
188 if (TREE_CODE (init) == INTEGER_CST)
189 *misalign = fold_convert (ssizetype, init);
191 /* Not constant, misalignment cannot be calculated. */
192 *misalign = NULL_TREE;
194 *initial_offset = fold_convert (ssizetype, init);
196 *step = evolution ? fold_convert (ssizetype, evolution) : ssize_int (0);
200 /* Recursive computation. */
201 if (!BINARY_CLASS_P (expr))
203 /* We expect to get binary expressions (PLUS/MINUS and MULT). */
204 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
206 fprintf (vect_dump, "Not binary expression ");
207 print_generic_expr (vect_dump, expr, TDF_SLIM);
211 oprnd0 = TREE_OPERAND (expr, 0);
212 oprnd1 = TREE_OPERAND (expr, 1);
214 if (!vect_analyze_offset_expr (oprnd0, loop, vectype_alignment, &left_offset,
215 &left_misalign, &left_step)
216 || !vect_analyze_offset_expr (oprnd1, loop, vectype_alignment,
217 &right_offset, &right_misalign, &right_step))
220 /* The type of the operation: plus, minus or mult. */
221 code = TREE_CODE (expr);
225 if (TREE_CODE (right_offset) != INTEGER_CST)
226 /* RIGHT_OFFSET can be not constant. For example, for arrays of variable
228 FORNOW: We don't support such cases. */
231 /* Strip conversions that don't narrow the mode. */
232 left_offset = vect_strip_conversion (left_offset);
235 /* Misalignment computation. */
236 if (SSA_VAR_P (left_offset))
238 /* If the left side contains variables that can't be substituted with
239 constants, we check if the right side is a multiple of ALIGNMENT.
241 if (integer_zerop (size_binop (TRUNC_MOD_EXPR, right_offset,
242 fold_convert (ssizetype, vectype_alignment))))
243 *misalign = ssize_int (0);
245 /* If the remainder is not zero or the right side isn't constant,
246 we can't compute misalignment. */
247 *misalign = NULL_TREE;
251 /* The left operand was successfully substituted with constant. */
253 /* In case of EXPR '(i * C1 + j) * C2', LEFT_MISALIGN is
255 *misalign = size_binop (code, left_misalign, right_misalign);
257 *misalign = NULL_TREE;
260 /* Step calculation. */
261 /* Multiply the step by the right operand. */
262 *step = size_binop (MULT_EXPR, left_step, right_offset);
267 /* Combine the recursive calculations for step and misalignment. */
268 *step = size_binop (code, left_step, right_step);
270 if (left_misalign && right_misalign)
271 *misalign = size_binop (code, left_misalign, right_misalign);
273 *misalign = NULL_TREE;
281 /* Compute offset. */
282 *initial_offset = fold_convert (ssizetype,
283 fold (build2 (code, TREE_TYPE (left_offset),
290 /* Function vect_determine_vectorization_factor
292 Determine the vectorization factor (VF). VF is the number of data elements
293 that are operated upon in parallel in a single iteration of the vectorized
294 loop. For example, when vectorizing a loop that operates on 4byte elements,
295 on a target with vector size (VS) 16byte, the VF is set to 4, since 4
296 elements can fit in a single vector register.
298 We currently support vectorization of loops in which all types operated upon
299 are of the same size. Therefore this function currently sets VF according to
300 the size of the types operated upon, and fails if there are multiple sizes
303 VF is also the factor by which the loop iterations are strip-mined, e.g.:
310 for (i=0; i<N; i+=VF){
311 a[i:VF] = b[i:VF] + c[i:VF];
316 vect_determine_vectorization_factor (loop_vec_info loop_vinfo)
318 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
319 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
320 int nbbs = loop->num_nodes;
321 block_stmt_iterator si;
322 unsigned int vectorization_factor = 0;
326 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
327 fprintf (vect_dump, "=== vect_determine_vectorization_factor ===");
329 for (i = 0; i < nbbs; i++)
331 basic_block bb = bbs[i];
333 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
335 tree stmt = bsi_stmt (si);
337 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
340 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
342 fprintf (vect_dump, "==> examining statement: ");
343 print_generic_expr (vect_dump, stmt, TDF_SLIM);
346 gcc_assert (stmt_info);
347 /* skip stmts which do not need to be vectorized. */
348 if (!STMT_VINFO_RELEVANT_P (stmt_info))
351 if (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))))
353 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
354 LOOP_LOC (loop_vinfo)))
356 fprintf (vect_dump, "not vectorized: vector stmt in loop:");
357 print_generic_expr (vect_dump, stmt, TDF_SLIM);
362 if (STMT_VINFO_DATA_REF (stmt_info))
363 scalar_type = TREE_TYPE (DR_REF (STMT_VINFO_DATA_REF (stmt_info)));
364 else if (TREE_CODE (stmt) == MODIFY_EXPR)
365 scalar_type = TREE_TYPE (TREE_OPERAND (stmt, 0));
367 scalar_type = TREE_TYPE (stmt);
369 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
371 fprintf (vect_dump, "get vectype for scalar type: ");
372 print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
375 vectype = get_vectype_for_scalar_type (scalar_type);
378 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
379 LOOP_LOC (loop_vinfo)))
381 fprintf (vect_dump, "not vectorized: unsupported data-type ");
382 print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
386 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
388 fprintf (vect_dump, "vectype: ");
389 print_generic_expr (vect_dump, vectype, TDF_SLIM);
391 STMT_VINFO_VECTYPE (stmt_info) = vectype;
393 nunits = TYPE_VECTOR_SUBPARTS (vectype);
394 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
395 fprintf (vect_dump, "nunits = %d", nunits);
397 if (vectorization_factor)
399 /* FORNOW: don't allow mixed units.
400 This restriction will be relaxed in the future. */
401 if (nunits != vectorization_factor)
403 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
404 LOOP_LOC (loop_vinfo)))
405 fprintf (vect_dump, "not vectorized: mixed data-types");
410 vectorization_factor = nunits;
412 #ifdef ENABLE_CHECKING
413 gcc_assert (GET_MODE_SIZE (TYPE_MODE (scalar_type))
414 * vectorization_factor == UNITS_PER_SIMD_WORD);
419 /* TODO: Analyze cost. Decide if worth while to vectorize. */
421 if (vectorization_factor <= 1)
423 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
424 LOOP_LOC (loop_vinfo)))
425 fprintf (vect_dump, "not vectorized: unsupported data-type");
428 LOOP_VINFO_VECT_FACTOR (loop_vinfo) = vectorization_factor;
434 /* Function vect_analyze_operations.
436 Scan the loop stmts and make sure they are all vectorizable. */
439 vect_analyze_operations (loop_vec_info loop_vinfo)
441 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
442 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
443 int nbbs = loop->num_nodes;
444 block_stmt_iterator si;
445 unsigned int vectorization_factor = 0;
449 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
450 fprintf (vect_dump, "=== vect_analyze_operations ===");
452 gcc_assert (LOOP_VINFO_VECT_FACTOR (loop_vinfo));
453 vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
455 for (i = 0; i < nbbs; i++)
457 basic_block bb = bbs[i];
459 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
461 tree stmt = bsi_stmt (si);
462 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
464 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
466 fprintf (vect_dump, "==> examining statement: ");
467 print_generic_expr (vect_dump, stmt, TDF_SLIM);
470 gcc_assert (stmt_info);
472 /* skip stmts which do not need to be vectorized.
473 this is expected to include:
474 - the COND_EXPR which is the loop exit condition
475 - any LABEL_EXPRs in the loop
476 - computations that are used only for array indexing or loop
479 if (!STMT_VINFO_RELEVANT_P (stmt_info))
481 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
482 fprintf (vect_dump, "irrelevant.");
486 #ifdef ENABLE_CHECKING
487 if (STMT_VINFO_RELEVANT_P (stmt_info))
489 gcc_assert (!VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))));
490 gcc_assert (STMT_VINFO_VECTYPE (stmt_info));
494 ok = (vectorizable_operation (stmt, NULL, NULL)
495 || vectorizable_assignment (stmt, NULL, NULL)
496 || vectorizable_load (stmt, NULL, NULL)
497 || vectorizable_store (stmt, NULL, NULL)
498 || vectorizable_condition (stmt, NULL, NULL));
502 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
503 LOOP_LOC (loop_vinfo)))
505 fprintf (vect_dump, "not vectorized: stmt not supported: ");
506 print_generic_expr (vect_dump, stmt, TDF_SLIM);
513 /* TODO: Analyze cost. Decide if worth while to vectorize. */
515 if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
516 && vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
518 "vectorization_factor = %d, niters = " HOST_WIDE_INT_PRINT_DEC,
519 vectorization_factor, LOOP_VINFO_INT_NITERS (loop_vinfo));
521 if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
522 && LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor)
524 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
525 LOOP_LOC (loop_vinfo)))
526 fprintf (vect_dump, "not vectorized: iteration count too small.");
530 if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
531 || LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0)
533 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
534 fprintf (vect_dump, "epilog loop required.");
535 if (!vect_can_advance_ivs_p (loop_vinfo))
537 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
538 LOOP_LOC (loop_vinfo)))
540 "not vectorized: can't create epilog loop 1.");
543 if (!slpeel_can_duplicate_loop_p (loop, loop->single_exit))
545 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
546 LOOP_LOC (loop_vinfo)))
548 "not vectorized: can't create epilog loop 2.");
557 /* Function exist_non_indexing_operands_for_use_p
559 USE is one of the uses attached to STMT. Check if USE is
560 used in STMT for anything other than indexing an array. */
563 exist_non_indexing_operands_for_use_p (tree use, tree stmt)
566 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
568 /* USE corresponds to some operand in STMT. If there is no data
569 reference in STMT, then any operand that corresponds to USE
570 is not indexing an array. */
571 if (!STMT_VINFO_DATA_REF (stmt_info))
574 /* STMT has a data_ref. FORNOW this means that its of one of
578 (This should have been verified in analyze_data_refs).
580 'var' in the second case corresponds to a def, not a use,
581 so USE cannot correspond to any operands that are not used
584 Therefore, all we need to check is if STMT falls into the
585 first case, and whether var corresponds to USE. */
587 if (TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
590 operand = TREE_OPERAND (stmt, 1);
592 if (TREE_CODE (operand) != SSA_NAME)
602 /* Function vect_analyze_scalar_cycles.
604 Examine the cross iteration def-use cycles of scalar variables, by
605 analyzing the loop (scalar) PHIs; verify that the cross iteration def-use
606 cycles that they represent do not impede vectorization.
608 FORNOW: Reduction as in the following loop, is not supported yet:
612 The cross-iteration cycle corresponding to variable 'sum' will be
613 considered too complicated and will impede vectorization.
615 FORNOW: Induction as in the following loop, is not supported yet:
620 However, the following loop *is* vectorizable:
625 In both loops there exists a def-use cycle for the variable i:
626 loop: i_2 = PHI (i_0, i_1)
631 The evolution of the above cycle is considered simple enough,
632 however, we also check that the cycle does not need to be
633 vectorized, i.e - we check that the variable that this cycle
634 defines is only used for array indexing or in stmts that do not
635 need to be vectorized. This is not the case in loop2, but it
636 *is* the case in loop3. */
639 vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
642 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
643 basic_block bb = loop->header;
646 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
647 fprintf (vect_dump, "=== vect_analyze_scalar_cycles ===");
649 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
651 tree access_fn = NULL;
653 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
655 fprintf (vect_dump, "Analyze phi: ");
656 print_generic_expr (vect_dump, phi, TDF_SLIM);
659 /* Skip virtual phi's. The data dependences that are associated with
660 virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
662 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
664 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
665 fprintf (vect_dump, "virtual phi. skip.");
669 /* Analyze the evolution function. */
671 /* FORNOW: The only scalar cross-iteration cycles that we allow are
672 those of loop induction variables; This property is verified here.
674 Furthermore, if that induction variable is used in an operation
675 that needs to be vectorized (i.e, is not solely used to index
676 arrays and check the exit condition) - we do not support its
677 vectorization yet. This property is verified in vect_is_simple_use,
678 during vect_analyze_operations. */
680 access_fn = /* instantiate_parameters
682 analyze_scalar_evolution (loop, PHI_RESULT (phi));
686 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
687 LOOP_LOC (loop_vinfo)))
688 fprintf (vect_dump, "not vectorized: unsupported scalar cycle.");
692 if (vect_print_dump_info (REPORT_DETAILS,
693 LOOP_LOC (loop_vinfo)))
695 fprintf (vect_dump, "Access function of PHI: ");
696 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
699 if (!vect_is_simple_iv_evolution (loop->num, access_fn, &dummy, &dummy))
701 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
702 LOOP_LOC (loop_vinfo)))
703 fprintf (vect_dump, "not vectorized: unsupported scalar cycle.");
712 /* Function vect_base_addr_differ_p.
714 This is the simplest data dependence test: determines whether the
715 data references A and B access the same array/region. Returns
716 false when the property is not computable at compile time.
717 Otherwise return true, and DIFFER_P will record the result. This
718 utility will not be necessary when alias_sets_conflict_p will be
719 less conservative. */
722 vect_base_addr_differ_p (struct data_reference *dra,
723 struct data_reference *drb,
726 tree stmt_a = DR_STMT (dra);
727 stmt_vec_info stmt_info_a = vinfo_for_stmt (stmt_a);
728 tree stmt_b = DR_STMT (drb);
729 stmt_vec_info stmt_info_b = vinfo_for_stmt (stmt_b);
730 tree addr_a = STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info_a);
731 tree addr_b = STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info_b);
732 tree type_a = TREE_TYPE (addr_a);
733 tree type_b = TREE_TYPE (addr_b);
734 HOST_WIDE_INT alias_set_a, alias_set_b;
736 gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b));
738 /* Both references are ADDR_EXPR, i.e., we have the objects. */
739 if (TREE_CODE (addr_a) == ADDR_EXPR && TREE_CODE (addr_b) == ADDR_EXPR)
740 return array_base_name_differ_p (dra, drb, differ_p);
742 alias_set_a = (TREE_CODE (addr_a) == ADDR_EXPR) ?
743 get_alias_set (TREE_OPERAND (addr_a, 0)) : get_alias_set (addr_a);
744 alias_set_b = (TREE_CODE (addr_b) == ADDR_EXPR) ?
745 get_alias_set (TREE_OPERAND (addr_b, 0)) : get_alias_set (addr_b);
747 if (!alias_sets_conflict_p (alias_set_a, alias_set_b))
753 /* An instruction writing through a restricted pointer is "independent" of any
754 instruction reading or writing through a different pointer, in the same
756 else if ((TYPE_RESTRICT (type_a) && !DR_IS_READ (dra))
757 || (TYPE_RESTRICT (type_b) && !DR_IS_READ (drb)))
766 /* Function vect_analyze_data_ref_dependence.
768 Return TRUE if there (might) exist a dependence between a memory-reference
769 DRA and a memory-reference DRB. */
772 vect_analyze_data_ref_dependence (struct data_reference *dra,
773 struct data_reference *drb,
774 loop_vec_info loop_vinfo)
777 struct data_dependence_relation *ddr;
778 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
779 int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
781 unsigned int loop_depth = 0;
782 struct loop *loop_nest = loop;
785 if (!vect_base_addr_differ_p (dra, drb, &differ_p))
787 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
788 LOOP_LOC (loop_vinfo)))
791 "not vectorized: can't determine dependence between: ");
792 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
793 fprintf (vect_dump, " and ");
794 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
802 ddr = initialize_data_dependence_relation (dra, drb);
803 compute_affine_dependence (ddr);
805 if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
808 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
810 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
811 LOOP_LOC (loop_vinfo)))
814 "not vectorized: can't determine dependence between ");
815 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
816 fprintf (vect_dump, " and ");
817 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
822 /* Find loop depth. */
825 if (loop_nest->outer && loop_nest->outer->outer)
827 loop_nest = loop_nest->outer;
834 /* Compute distance vector. */
835 compute_subscript_distance (ddr);
836 build_classic_dist_vector (ddr, vect_loops_num, loop_nest->depth);
838 if (!DDR_DIST_VECT (ddr))
840 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
841 LOOP_LOC (loop_vinfo)))
843 fprintf (vect_dump, "not vectorized: bad dist vector for ");
844 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
845 fprintf (vect_dump, " and ");
846 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
851 dist = DDR_DIST_VECT (ddr)[loop_depth];
853 /* Same loop iteration. */
856 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
857 fprintf (vect_dump, "dependence distance 0.");
861 if (dist >= vectorization_factor)
862 /* Dependence distance does not create dependence, as far as vectorization
863 is concerned, in this case. */
866 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
867 LOOP_LOC (loop_vinfo)))
870 "not vectorized: possible dependence between data-refs ");
871 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
872 fprintf (vect_dump, " and ");
873 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
880 /* Function vect_analyze_data_ref_dependences.
882 Examine all the data references in the loop, and make sure there do not
883 exist any data dependences between them. */
886 vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo)
889 varray_type loop_write_refs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
890 varray_type loop_read_refs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
892 /* Examine store-store (output) dependences. */
894 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
895 fprintf (vect_dump, "=== vect_analyze_dependences ===");
897 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
898 fprintf (vect_dump, "compare all store-store pairs.");
900 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_refs); i++)
902 for (j = i + 1; j < VARRAY_ACTIVE_SIZE (loop_write_refs); j++)
904 struct data_reference *dra =
905 VARRAY_GENERIC_PTR (loop_write_refs, i);
906 struct data_reference *drb =
907 VARRAY_GENERIC_PTR (loop_write_refs, j);
908 if (vect_analyze_data_ref_dependence (dra, drb, loop_vinfo))
913 /* Examine load-store (true/anti) dependences. */
915 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
916 fprintf (vect_dump, "compare all load-store pairs.");
918 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_refs); i++)
920 for (j = 0; j < VARRAY_ACTIVE_SIZE (loop_write_refs); j++)
922 struct data_reference *dra = VARRAY_GENERIC_PTR (loop_read_refs, i);
923 struct data_reference *drb =
924 VARRAY_GENERIC_PTR (loop_write_refs, j);
925 if (vect_analyze_data_ref_dependence (dra, drb, loop_vinfo))
934 /* Function vect_compute_data_ref_alignment
936 Compute the misalignment of the data reference DR.
939 1. If during the misalignment computation it is found that the data reference
940 cannot be vectorized then false is returned.
941 2. DR_MISALIGNMENT (DR) is defined.
943 FOR NOW: No analysis is actually performed. Misalignment is calculated
944 only for trivial cases. TODO. */
947 vect_compute_data_ref_alignment (struct data_reference *dr)
949 tree stmt = DR_STMT (dr);
950 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
951 tree ref = DR_REF (dr);
953 tree base, alignment;
957 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
958 fprintf (vect_dump, "vect_compute_data_ref_alignment:");
960 /* Initialize misalignment to unknown. */
961 DR_MISALIGNMENT (dr) = -1;
963 misalign = STMT_VINFO_VECT_MISALIGNMENT (stmt_info);
964 base_aligned_p = STMT_VINFO_VECT_BASE_ALIGNED_P (stmt_info);
965 base = build_fold_indirect_ref (STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info));
966 vectype = STMT_VINFO_VECTYPE (stmt_info);
970 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
972 fprintf (vect_dump, "Unknown alignment for access: ");
973 print_generic_expr (vect_dump, base, TDF_SLIM);
980 if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype)))
982 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
984 fprintf (vect_dump, "can't force alignment of ref: ");
985 print_generic_expr (vect_dump, ref, TDF_SLIM);
990 /* Force the alignment of the decl.
991 NOTE: This is the only change to the code we make during
992 the analysis phase, before deciding to vectorize the loop. */
993 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
994 fprintf (vect_dump, "force alignment");
995 DECL_ALIGN (base) = TYPE_ALIGN (vectype);
996 DECL_USER_ALIGN (base) = 1;
999 /* At this point we assume that the base is aligned. */
1000 gcc_assert (base_aligned_p
1001 || (TREE_CODE (base) == VAR_DECL
1002 && DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
1004 /* Alignment required, in bytes: */
1005 alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT);
1007 /* Modulo alignment. */
1008 misalign = size_binop (TRUNC_MOD_EXPR, misalign, alignment);
1009 if (tree_int_cst_sgn (misalign) < 0)
1011 /* Negative misalignment value. */
1012 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1013 fprintf (vect_dump, "unexpected misalign value");
1017 DR_MISALIGNMENT (dr) = tree_low_cst (misalign, 1);
1019 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1020 fprintf (vect_dump, "misalign = %d bytes", DR_MISALIGNMENT (dr));
1026 /* Function vect_compute_data_refs_alignment
1028 Compute the misalignment of data references in the loop.
1029 This pass may take place at function granularity instead of at loop
1032 FOR NOW: No analysis is actually performed. Misalignment is calculated
1033 only for trivial cases. TODO. */
1036 vect_compute_data_refs_alignment (loop_vec_info loop_vinfo)
1038 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1039 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1042 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1044 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1045 if (!vect_compute_data_ref_alignment (dr))
1049 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1051 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1052 if (!vect_compute_data_ref_alignment (dr))
1060 /* Function vect_enhance_data_refs_alignment
1062 This pass will use loop versioning and loop peeling in order to enhance
1063 the alignment of data references in the loop.
1065 FOR NOW: we assume that whatever versioning/peeling takes place, only the
1066 original loop is to be vectorized; Any other loops that are created by
1067 the transformations performed in this pass - are not supposed to be
1068 vectorized. This restriction will be relaxed. */
1071 vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
1073 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1074 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1075 varray_type datarefs;
1076 struct data_reference *dr0 = NULL;
1080 This pass will require a cost model to guide it whether to apply peeling
1081 or versioning or a combination of the two. For example, the scheme that
1082 intel uses when given a loop with several memory accesses, is as follows:
1083 choose one memory access ('p') which alignment you want to force by doing
1084 peeling. Then, either (1) generate a loop in which 'p' is aligned and all
1085 other accesses are not necessarily aligned, or (2) use loop versioning to
1086 generate one loop in which all accesses are aligned, and another loop in
1087 which only 'p' is necessarily aligned.
1089 ("Automatic Intra-Register Vectorization for the Intel Architecture",
1090 Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International
1091 Journal of Parallel Programming, Vol. 30, No. 2, April 2002.)
1093 Devising a cost model is the most critical aspect of this work. It will
1094 guide us on which access to peel for, whether to use loop versioning, how
1095 many versions to create, etc. The cost model will probably consist of
1096 generic considerations as well as target specific considerations (on
1097 powerpc for example, misaligned stores are more painful than misaligned
1100 Here is the general steps involved in alignment enhancements:
1102 -- original loop, before alignment analysis:
1103 for (i=0; i<N; i++){
1104 x = q[i]; # DR_MISALIGNMENT(q) = unknown
1105 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1108 -- After vect_compute_data_refs_alignment:
1109 for (i=0; i<N; i++){
1110 x = q[i]; # DR_MISALIGNMENT(q) = 3
1111 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1114 -- Possibility 1: we do loop versioning:
1116 for (i=0; i<N; i++){ # loop 1A
1117 x = q[i]; # DR_MISALIGNMENT(q) = 3
1118 p[i] = y; # DR_MISALIGNMENT(p) = 0
1122 for (i=0; i<N; i++){ # loop 1B
1123 x = q[i]; # DR_MISALIGNMENT(q) = 3
1124 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
1128 -- Possibility 2: we do loop peeling:
1129 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
1133 for (i = 3; i < N; i++){ # loop 2A
1134 x = q[i]; # DR_MISALIGNMENT(q) = 0
1135 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1138 -- Possibility 3: combination of loop peeling and versioning:
1139 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
1144 for (i = 3; i<N; i++){ # loop 3A
1145 x = q[i]; # DR_MISALIGNMENT(q) = 0
1146 p[i] = y; # DR_MISALIGNMENT(p) = 0
1150 for (i = 3; i<N; i++){ # loop 3B
1151 x = q[i]; # DR_MISALIGNMENT(q) = 0
1152 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
1156 These loops are later passed to loop_transform to be vectorized. The
1157 vectorizer will use the alignment information to guide the transformation
1158 (whether to generate regular loads/stores, or with special handling for
1162 /* (1) Peeling to force alignment. */
1164 /* (1.1) Decide whether to perform peeling, and how many iterations to peel:
1166 + How many accesses will become aligned due to the peeling
1167 - How many accesses will become unaligned due to the peeling,
1168 and the cost of misaligned accesses.
1169 - The cost of peeling (the extra runtime checks, the increase
1172 The scheme we use FORNOW: peel to force the alignment of the first
1173 misaligned store in the loop.
1174 Rationale: misaligned stores are not yet supported.
1176 TODO: Use a better cost model. */
1178 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1180 dr0 = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1181 if (!aligned_access_p (dr0))
1183 LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0;
1184 LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0);
1189 /* (1.2) Update the alignment info according to the peeling factor.
1190 If the misalignment of the DR we peel for is M, then the
1191 peeling factor is VF - M, and the misalignment of each access DR_i
1192 in the loop is DR_MISALIGNMENT (DR_i) + VF - M.
1193 If the misalignment of the DR we peel for is unknown, then the
1194 misalignment of each access DR_i in the loop is also unknown.
1196 TODO: - consider accesses that are known to have the same
1197 alignment, even if that alignment is unknown. */
1199 if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
1204 if (known_alignment_for_access_p (dr0))
1206 /* Since it's known at compile time, compute the number of iterations
1207 in the peeled loop (the peeling factor) for use in updating
1208 DR_MISALIGNMENT values. The peeling factor is the vectorization
1209 factor minus the misalignment as an element count. */
1210 mis = DR_MISALIGNMENT (dr0);
1211 mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
1212 npeel = LOOP_VINFO_VECT_FACTOR (loop_vinfo) - mis;
1215 datarefs = loop_write_datarefs;
1216 for (j = 0; j < 2; j++)
1218 for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
1220 struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
1224 if (known_alignment_for_access_p (dr)
1225 && DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr0))
1226 DR_MISALIGNMENT (dr) = 0;
1227 else if (known_alignment_for_access_p (dr)
1228 && known_alignment_for_access_p (dr0))
1230 int drsize = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
1232 DR_MISALIGNMENT (dr) += npeel * drsize;
1233 DR_MISALIGNMENT (dr) %= UNITS_PER_SIMD_WORD;
1236 DR_MISALIGNMENT (dr) = -1;
1238 datarefs = loop_read_datarefs;
1241 DR_MISALIGNMENT (dr0) = 0;
1246 /* Function vect_analyze_data_refs_alignment
1248 Analyze the alignment of the data-references in the loop.
1249 FOR NOW: Until support for misliagned accesses is in place, only if all
1250 accesses are aligned can the loop be vectorized. This restriction will be
1254 vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo)
1256 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1257 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1258 enum dr_alignment_support supportable_dr_alignment;
1261 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1262 fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ===");
1265 /* This pass may take place at function granularity instead of at loop
1268 if (!vect_compute_data_refs_alignment (loop_vinfo))
1270 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1271 LOOP_LOC (loop_vinfo)))
1273 "not vectorized: can't calculate alignment for data ref.");
1278 /* This pass will decide on using loop versioning and/or loop peeling in
1279 order to enhance the alignment of data references in the loop. */
1281 vect_enhance_data_refs_alignment (loop_vinfo);
1284 /* Finally, check that all the data references in the loop can be
1285 handled with respect to their alignment. */
1287 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1289 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1290 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1291 if (!supportable_dr_alignment)
1293 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1294 LOOP_LOC (loop_vinfo)))
1295 fprintf (vect_dump, "not vectorized: unsupported unaligned load.");
1298 if (supportable_dr_alignment != dr_aligned
1299 && (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo))))
1300 fprintf (vect_dump, "Vectorizing an unaligned access.");
1302 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1304 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1305 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1306 if (!supportable_dr_alignment)
1308 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1309 LOOP_LOC (loop_vinfo)))
1310 fprintf (vect_dump, "not vectorized: unsupported unaligned store.");
1313 if (supportable_dr_alignment != dr_aligned
1314 && (vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo))))
1315 fprintf (vect_dump, "Vectorizing an unaligned access.");
1317 if (LOOP_VINFO_UNALIGNED_DR (loop_vinfo)
1318 && vect_print_dump_info (REPORT_ALIGNMENT, LOOP_LOC (loop_vinfo)))
1319 fprintf (vect_dump, "Alignment of access forced using peeling.");
1325 /* Function vect_analyze_data_ref_access.
1327 Analyze the access pattern of the data-reference DR. For now, a data access
1328 has to consecutive to be considered vectorizable. */
1331 vect_analyze_data_ref_access (struct data_reference *dr)
1333 tree stmt = DR_STMT (dr);
1334 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1335 tree step = STMT_VINFO_VECT_STEP (stmt_info);
1336 tree scalar_type = TREE_TYPE (DR_REF (dr));
1338 if (!step || tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
1340 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1341 fprintf (vect_dump, "not consecutive access");
1348 /* Function vect_analyze_data_ref_accesses.
1350 Analyze the access pattern of all the data references in the loop.
1352 FORNOW: the only access pattern that is considered vectorizable is a
1353 simple step 1 (consecutive) access.
1355 FORNOW: handle only arrays and pointer accesses. */
1358 vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo)
1361 varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
1362 varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
1364 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1365 fprintf (vect_dump, "=== vect_analyze_data_ref_accesses ===");
1367 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
1369 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
1370 bool ok = vect_analyze_data_ref_access (dr);
1373 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1374 LOOP_LOC (loop_vinfo)))
1375 fprintf (vect_dump, "not vectorized: complicated access pattern.");
1380 for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
1382 struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
1383 bool ok = vect_analyze_data_ref_access (dr);
1386 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1387 LOOP_LOC (loop_vinfo)))
1388 fprintf (vect_dump, "not vectorized: complicated access pattern.");
1397 /* Function vect_analyze_pointer_ref_access.
1400 STMT - a stmt that contains a data-ref.
1401 MEMREF - a data-ref in STMT, which is an INDIRECT_REF.
1402 ACCESS_FN - the access function of MEMREF.
1405 If the data-ref access is vectorizable, return a data_reference structure
1406 that represents it (DR). Otherwise - return NULL.
1407 STEP - the stride of MEMREF in the loop.
1408 INIT - the initial condition of MEMREF in the loop.
1411 static struct data_reference *
1412 vect_analyze_pointer_ref_access (tree memref, tree stmt, bool is_read,
1413 tree access_fn, tree *ptr_init, tree *ptr_step)
1415 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1416 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1417 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1419 tree reftype, innertype;
1420 tree indx_access_fn;
1421 int loopnum = loop->num;
1422 struct data_reference *dr;
1424 if (!vect_is_simple_iv_evolution (loopnum, access_fn, &init, &step))
1426 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1427 LOOP_LOC (loop_vinfo)))
1428 fprintf (vect_dump, "not vectorized: pointer access is not simple.");
1434 if (!expr_invariant_in_loop_p (loop, init))
1436 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1437 LOOP_LOC (loop_vinfo)))
1439 "not vectorized: initial condition is not loop invariant.");
1443 if (TREE_CODE (step) != INTEGER_CST)
1445 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1446 LOOP_LOC (loop_vinfo)))
1448 "not vectorized: non constant step for pointer access.");
1452 reftype = TREE_TYPE (TREE_OPERAND (memref, 0));
1453 if (!POINTER_TYPE_P (reftype))
1455 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1456 LOOP_LOC (loop_vinfo)))
1457 fprintf (vect_dump, "not vectorized: unexpected pointer access form.");
1461 if (!POINTER_TYPE_P (TREE_TYPE (init)))
1463 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1464 LOOP_LOC (loop_vinfo)))
1465 fprintf (vect_dump, "not vectorized: unexpected pointer access form.");
1469 *ptr_step = fold_convert (ssizetype, step);
1470 innertype = TREE_TYPE (reftype);
1471 if (!COMPLETE_TYPE_P (innertype))
1473 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1474 LOOP_LOC (loop_vinfo)))
1475 fprintf (vect_dump, "not vectorized: pointer to incomplete type.");
1479 /* Check that STEP is a multiple of type size. */
1480 if (!integer_zerop (size_binop (TRUNC_MOD_EXPR, *ptr_step,
1481 fold_convert (ssizetype, TYPE_SIZE_UNIT (innertype)))))
1483 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1484 LOOP_LOC (loop_vinfo)))
1485 fprintf (vect_dump, "not vectorized: non consecutive access.");
1490 build_polynomial_chrec (loopnum, integer_zero_node, integer_one_node);
1491 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1493 fprintf (vect_dump, "Access function of ptr indx: ");
1494 print_generic_expr (vect_dump, indx_access_fn, TDF_SLIM);
1496 dr = init_data_ref (stmt, memref, NULL_TREE, indx_access_fn, is_read);
1502 /* Function vect_address_analysis
1504 Return the BASE of the address expression EXPR.
1505 Also compute the INITIAL_OFFSET from BASE, MISALIGN and STEP.
1508 EXPR - the address expression that is being analyzed
1509 STMT - the statement that contains EXPR or its original memory reference
1510 IS_READ - TRUE if STMT reads from EXPR, FALSE if writes to EXPR
1511 VECTYPE - the type that defines the alignment (i.e, we compute
1512 alignment relative to TYPE_ALIGN(VECTYPE))
1513 DR - data_reference struct for the original memory reference
1516 BASE (returned value) - the base of the data reference EXPR.
1517 INITIAL_OFFSET - initial offset of EXPR from BASE (an expression)
1518 MISALIGN - offset of EXPR from BASE in bytes (a constant) or NULL_TREE if the
1519 computation is impossible
1520 STEP - evolution of EXPR in the loop
1521 BASE_ALIGNED - indicates if BASE is aligned
1523 If something unexpected is encountered (an unsupported form of data-ref),
1524 then NULL_TREE is returned.
1528 vect_address_analysis (tree expr, tree stmt, bool is_read, tree vectype,
1529 struct data_reference *dr, tree *offset, tree *misalign,
1530 tree *step, bool *base_aligned)
1532 tree oprnd0, oprnd1, base_address, offset_expr, base_addr0, base_addr1;
1533 tree address_offset = ssize_int (0), address_misalign = ssize_int (0);
1535 struct ptr_info_def *dummy1;
1538 switch (TREE_CODE (expr))
1542 /* EXPR is of form {base +/- offset} (or {offset +/- base}). */
1543 oprnd0 = TREE_OPERAND (expr, 0);
1544 oprnd1 = TREE_OPERAND (expr, 1);
1546 STRIP_NOPS (oprnd0);
1547 STRIP_NOPS (oprnd1);
1549 /* Recursively try to find the base of the address contained in EXPR.
1550 For offset, the returned base will be NULL. */
1551 base_addr0 = vect_address_analysis (oprnd0, stmt, is_read, vectype, dr,
1552 &address_offset, &address_misalign, step,
1555 base_addr1 = vect_address_analysis (oprnd1, stmt, is_read, vectype, dr,
1556 &address_offset, &address_misalign, step,
1559 /* We support cases where only one of the operands contains an
1561 if ((base_addr0 && base_addr1) || (!base_addr0 && !base_addr1))
1564 /* To revert STRIP_NOPS. */
1565 oprnd0 = TREE_OPERAND (expr, 0);
1566 oprnd1 = TREE_OPERAND (expr, 1);
1568 offset_expr = base_addr0 ?
1569 fold_convert (ssizetype, oprnd1) : fold_convert (ssizetype, oprnd0);
1571 /* EXPR is of form {base +/- offset} (or {offset +/- base}). If offset is
1572 a number, we can add it to the misalignment value calculated for base,
1573 otherwise, misalignment is NULL. */
1574 if (TREE_CODE (offset_expr) == INTEGER_CST && address_misalign)
1575 *misalign = size_binop (TREE_CODE (expr), address_misalign,
1578 *misalign = NULL_TREE;
1580 /* Combine offset (from EXPR {base + offset}) with the offset calculated
1582 *offset = size_binop (TREE_CODE (expr), address_offset, offset_expr);
1583 return base_addr0 ? base_addr0 : base_addr1;
1586 base_address = vect_object_analysis (TREE_OPERAND (expr, 0), stmt,
1587 is_read, vectype, &dr, offset,
1588 misalign, step, base_aligned,
1589 &dummy, &dummy1, &dummy2);
1590 return base_address;
1593 if (!POINTER_TYPE_P (TREE_TYPE (expr)))
1596 if (TYPE_ALIGN (TREE_TYPE (TREE_TYPE (expr))) < TYPE_ALIGN (vectype))
1598 if (vect_get_ptr_offset (expr, vectype, misalign))
1599 *base_aligned = true;
1601 *base_aligned = false;
1605 *base_aligned = true;
1606 *misalign = ssize_int (0);
1608 *offset = ssize_int (0);
1609 *step = ssize_int (0);
1618 /* Function vect_object_analysis
1620 Return the BASE of the data reference MEMREF.
1621 Also compute the INITIAL_OFFSET from BASE, MISALIGN and STEP.
1622 E.g., for EXPR a.b[i] + 4B, BASE is a, and OFFSET is the overall offset
1623 'a.b[i] + 4B' from a (can be an expression), MISALIGN is an OFFSET
1624 instantiated with initial_conditions of access_functions of variables,
1625 modulo alignment, and STEP is the evolution of the DR_REF in this loop.
1627 Function get_inner_reference is used for the above in case of ARRAY_REF and
1630 The structure of the function is as follows:
1632 Case 1. For handled_component_p refs
1633 1.1 call get_inner_reference
1634 1.1.1 analyze offset expr received from get_inner_reference
1635 1.2. build data-reference structure for MEMREF
1636 (fall through with BASE)
1637 Case 2. For declarations
1639 2.2 update DR_BASE_NAME if necessary for alias
1640 Case 3. For INDIRECT_REFs
1641 3.1 get the access function
1642 3.2 analyze evolution of MEMREF
1643 3.3 set data-reference structure for MEMREF
1644 3.4 call vect_address_analysis to analyze INIT of the access function
1647 Combine the results of object and address analysis to calculate
1648 INITIAL_OFFSET, STEP and misalignment info.
1651 MEMREF - the memory reference that is being analyzed
1652 STMT - the statement that contains MEMREF
1653 IS_READ - TRUE if STMT reads from MEMREF, FALSE if writes to MEMREF
1654 VECTYPE - the type that defines the alignment (i.e, we compute
1655 alignment relative to TYPE_ALIGN(VECTYPE))
1658 BASE_ADDRESS (returned value) - the base address of the data reference MEMREF
1659 E.g, if MEMREF is a.b[k].c[i][j] the returned
1661 DR - data_reference struct for MEMREF
1662 INITIAL_OFFSET - initial offset of MEMREF from BASE (an expression)
1663 MISALIGN - offset of MEMREF from BASE in bytes (a constant) or NULL_TREE if
1664 the computation is impossible
1665 STEP - evolution of the DR_REF in the loop
1666 BASE_ALIGNED - indicates if BASE is aligned
1667 MEMTAG - memory tag for aliasing purposes
1668 PTR_INFO - NULL or points-to aliasing info from a pointer SSA_NAME
1669 SUBVAR - Sub-variables of the variable
1671 If something unexpected is encountered (an unsupported form of data-ref),
1672 then NULL_TREE is returned. */
1675 vect_object_analysis (tree memref, tree stmt, bool is_read,
1676 tree vectype, struct data_reference **dr,
1677 tree *offset, tree *misalign, tree *step,
1678 bool *base_aligned, tree *memtag,
1679 struct ptr_info_def **ptr_info, subvar_t *subvars)
1681 tree base = NULL_TREE, base_address = NULL_TREE;
1682 tree object_offset = ssize_int (0), object_misalign = ssize_int (0);
1683 tree object_step = ssize_int (0), address_step = ssize_int (0);
1684 bool object_base_aligned = true, address_base_aligned = true;
1685 tree address_offset = ssize_int (0), address_misalign = ssize_int (0);
1686 HOST_WIDE_INT pbitsize, pbitpos;
1687 tree poffset, bit_pos_in_bytes;
1688 enum machine_mode pmode;
1689 int punsignedp, pvolatilep;
1690 tree ptr_step = ssize_int (0), ptr_init = NULL_TREE;
1691 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1692 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1693 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1694 struct data_reference *ptr_dr = NULL;
1695 tree access_fn, evolution_part, address_to_analyze;
1700 /* Case 1. handled_component_p refs. */
1701 if (handled_component_p (memref))
1703 /* 1.1 call get_inner_reference. */
1704 /* Find the base and the offset from it. */
1705 base = get_inner_reference (memref, &pbitsize, &pbitpos, &poffset,
1706 &pmode, &punsignedp, &pvolatilep, false);
1710 /* 1.1.1 analyze offset expr received from get_inner_reference. */
1712 && !vect_analyze_offset_expr (poffset, loop, TYPE_SIZE_UNIT (vectype),
1713 &object_offset, &object_misalign, &object_step))
1715 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1717 fprintf (vect_dump, "failed to compute offset or step for ");
1718 print_generic_expr (vect_dump, memref, TDF_SLIM);
1723 /* Add bit position to OFFSET and MISALIGN. */
1725 bit_pos_in_bytes = ssize_int (pbitpos/BITS_PER_UNIT);
1726 /* Check that there is no remainder in bits. */
1727 if (pbitpos%BITS_PER_UNIT)
1729 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1730 fprintf (vect_dump, "bit offset alignment.");
1733 object_offset = size_binop (PLUS_EXPR, bit_pos_in_bytes, object_offset);
1734 if (object_misalign)
1735 object_misalign = size_binop (PLUS_EXPR, object_misalign,
1738 /* Create data-reference for MEMREF. TODO: handle COMPONENT_REFs. */
1741 if (TREE_CODE (memref) == ARRAY_REF)
1742 *dr = analyze_array (stmt, memref, is_read);
1747 memref = base; /* To continue analysis of BASE. */
1751 /* Part 1: Case 2. Declarations. */
1752 if (DECL_P (memref))
1754 /* We expect to get a decl only if we already have a DR. */
1757 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1759 fprintf (vect_dump, "unhandled decl ");
1760 print_generic_expr (vect_dump, memref, TDF_SLIM);
1765 /* 2.1 check the alignment. */
1766 if (DECL_ALIGN (memref) >= TYPE_ALIGN (vectype))
1767 object_base_aligned = true;
1769 object_base_aligned = false;
1771 /* 2.2 update DR_BASE_NAME if necessary. */
1772 if (!DR_BASE_NAME ((*dr)))
1773 /* For alias analysis. In case the analysis of INDIRECT_REF brought
1775 DR_BASE_NAME ((*dr)) = memref;
1777 if (SSA_VAR_P (memref) && var_can_have_subvars (memref))
1778 *subvars = get_subvars_for_var (memref);
1779 base_address = build_fold_addr_expr (memref);
1783 /* Part 1: Case 3. INDIRECT_REFs. */
1784 else if (TREE_CODE (memref) == INDIRECT_REF)
1786 tree ptr_ref = TREE_OPERAND (memref, 0);
1787 if (TREE_CODE (ptr_ref) == SSA_NAME)
1788 *ptr_info = SSA_NAME_PTR_INFO (ptr_ref);
1790 /* 3.1 get the access function. */
1791 access_fn = analyze_scalar_evolution (loop, ptr_ref);
1794 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1795 LOOP_LOC (loop_vinfo)))
1796 fprintf (vect_dump, "not vectorized: complicated pointer access.");
1799 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1801 fprintf (vect_dump, "Access function of ptr: ");
1802 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
1805 /* 3.2 analyze evolution of MEMREF. */
1806 evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
1809 ptr_dr = vect_analyze_pointer_ref_access (memref, stmt, is_read,
1810 access_fn, &ptr_init, &ptr_step);
1814 object_step = size_binop (PLUS_EXPR, object_step, ptr_step);
1815 address_to_analyze = ptr_init;
1821 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1822 LOOP_LOC (loop_vinfo)))
1823 fprintf (vect_dump, "not vectorized: ptr is loop invariant.");
1826 /* Since there exists DR for MEMREF, we are analyzing the init of
1827 the access function, which not necessary has evolution in the
1829 address_to_analyze = initial_condition_in_loop_num (access_fn,
1833 /* 3.3 set data-reference structure for MEMREF. */
1834 *dr = (*dr) ? *dr : ptr_dr;
1836 /* 3.4 call vect_address_analysis to analyze INIT of the access
1838 base_address = vect_address_analysis (address_to_analyze, stmt, is_read,
1839 vectype, *dr, &address_offset, &address_misalign,
1840 &address_step, &address_base_aligned);
1844 switch (TREE_CODE (base_address))
1847 *memtag = get_var_ann (SSA_NAME_VAR (base_address))->type_mem_tag;
1848 if (!(*memtag) && TREE_CODE (TREE_OPERAND (memref, 0)) == SSA_NAME)
1849 *memtag = get_var_ann (
1850 SSA_NAME_VAR (TREE_OPERAND (memref, 0)))->type_mem_tag;
1853 *memtag = TREE_OPERAND (base_address, 0);
1856 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
1857 LOOP_LOC (loop_vinfo)))
1859 fprintf (vect_dump, "not vectorized: no memtag ref: ");
1860 print_generic_expr (vect_dump, memref, TDF_SLIM);
1867 /* MEMREF cannot be analyzed. */
1870 if (SSA_VAR_P (*memtag) && var_can_have_subvars (*memtag))
1871 *subvars = get_subvars_for_var (*memtag);
1873 /* Part 2: Combine the results of object and address analysis to calculate
1874 INITIAL_OFFSET, STEP and misalignment info. */
1875 *offset = size_binop (PLUS_EXPR, object_offset, address_offset);
1876 if (object_misalign && address_misalign)
1877 *misalign = size_binop (PLUS_EXPR, object_misalign, address_misalign);
1879 *misalign = NULL_TREE;
1880 *step = size_binop (PLUS_EXPR, object_step, address_step);
1881 *base_aligned = object_base_aligned && address_base_aligned;
1883 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1885 fprintf (vect_dump, "Results of object analysis for: ");
1886 print_generic_expr (vect_dump, memref, TDF_SLIM);
1887 fprintf (vect_dump, "\n\tbase_address: ");
1888 print_generic_expr (vect_dump, base_address, TDF_SLIM);
1889 fprintf (vect_dump, "\n\toffset: ");
1890 print_generic_expr (vect_dump, *offset, TDF_SLIM);
1891 fprintf (vect_dump, "\n\tstep: ");
1892 print_generic_expr (vect_dump, *step, TDF_SLIM);
1893 fprintf (vect_dump, "\n\tbase aligned %d\n\tmisalign: ", *base_aligned);
1894 print_generic_expr (vect_dump, *misalign, TDF_SLIM);
1896 return base_address;
1900 /* Function vect_analyze_data_refs.
1902 Find all the data references in the loop.
1904 The general structure of the analysis of data refs in the vectorizer is as
1906 1- vect_analyze_data_refs(loop):
1907 Find and analyze all data-refs in the loop:
1909 base_address = vect_object_analysis(ref)
1910 1.1- vect_object_analysis(ref):
1911 Analyze ref, and build a DR (data_referece struct) for it;
1912 compute base, initial_offset, step and alignment.
1913 Call get_inner_reference for refs handled in this function.
1914 Call vect_addr_analysis(addr) to analyze pointer type expressions.
1915 Set ref_stmt.base, ref_stmt.initial_offset, ref_stmt.alignment,
1916 ref_stmt.memtag, ref_stmt.ptr_info and ref_stmt.step accordingly.
1917 2- vect_analyze_dependences(): apply dependence testing using ref_stmt.DR
1918 3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok.
1919 4- vect_analyze_drs_access(): check that ref_stmt.step is ok.
1921 FORNOW: Handle aligned INDIRECT_REFs and ARRAY_REFs
1922 which base is really an array (not a pointer) and which alignment
1923 can be forced. This restriction will be relaxed. */
1926 vect_analyze_data_refs (loop_vec_info loop_vinfo)
1928 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1929 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
1930 int nbbs = loop->num_nodes;
1931 block_stmt_iterator si;
1933 struct data_reference *dr;
1935 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1936 fprintf (vect_dump, "=== vect_analyze_data_refs ===");
1938 for (j = 0; j < nbbs; j++)
1940 basic_block bb = bbs[j];
1941 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
1943 bool is_read = false;
1944 tree stmt = bsi_stmt (si);
1945 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1946 v_may_def_optype v_may_defs = STMT_V_MAY_DEF_OPS (stmt);
1947 v_must_def_optype v_must_defs = STMT_V_MUST_DEF_OPS (stmt);
1948 vuse_optype vuses = STMT_VUSE_OPS (stmt);
1949 varray_type *datarefs = NULL;
1950 int nvuses, nv_may_defs, nv_must_defs;
1952 tree scalar_type, vectype;
1953 tree base, offset, misalign, step, tag;
1954 struct ptr_info_def *ptr_info;
1956 subvar_t subvars = NULL;
1958 /* Assumption: there exists a data-ref in stmt, if and only if
1959 it has vuses/vdefs. */
1961 if (!vuses && !v_may_defs && !v_must_defs)
1964 nvuses = NUM_VUSES (vuses);
1965 nv_may_defs = NUM_V_MAY_DEFS (v_may_defs);
1966 nv_must_defs = NUM_V_MUST_DEFS (v_must_defs);
1968 if (nvuses && (nv_may_defs || nv_must_defs))
1970 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1972 fprintf (vect_dump, "unexpected vdefs and vuses in stmt: ");
1973 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1978 if (TREE_CODE (stmt) != MODIFY_EXPR)
1980 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1982 fprintf (vect_dump, "unexpected vops in stmt: ");
1983 print_generic_expr (vect_dump, stmt, TDF_SLIM);
1990 memref = TREE_OPERAND (stmt, 1);
1991 datarefs = &(LOOP_VINFO_DATAREF_READS (loop_vinfo));
1996 memref = TREE_OPERAND (stmt, 0);
1997 datarefs = &(LOOP_VINFO_DATAREF_WRITES (loop_vinfo));
2001 scalar_type = TREE_TYPE (memref);
2002 vectype = get_vectype_for_scalar_type (scalar_type);
2005 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2007 fprintf (vect_dump, "no vectype for stmt: ");
2008 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2009 fprintf (vect_dump, " scalar_type: ");
2010 print_generic_expr (vect_dump, scalar_type, TDF_DETAILS);
2012 /* It is not possible to vectorize this data reference. */
2015 /* Analyze MEMREF. If it is of a supported form, build data_reference
2016 struct for it (DR). */
2018 base = vect_object_analysis (memref, stmt, is_read, vectype, &dr,
2019 &offset, &misalign, &step,
2020 &base_aligned, &tag, &ptr_info,
2024 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2025 LOOP_LOC (loop_vinfo)))
2027 fprintf (vect_dump, "not vectorized: unhandled data ref: ");
2028 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2032 STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info) = base;
2033 STMT_VINFO_VECT_INIT_OFFSET (stmt_info) = offset;
2034 STMT_VINFO_VECT_STEP (stmt_info) = step;
2035 STMT_VINFO_VECT_MISALIGNMENT (stmt_info) = misalign;
2036 STMT_VINFO_VECT_BASE_ALIGNED_P (stmt_info) = base_aligned;
2037 STMT_VINFO_MEMTAG (stmt_info) = tag;
2038 STMT_VINFO_PTR_INFO (stmt_info) = ptr_info;
2039 STMT_VINFO_SUBVARS (stmt_info) = subvars;
2040 STMT_VINFO_VECTYPE (stmt_info) = vectype;
2041 VARRAY_PUSH_GENERIC_PTR (*datarefs, dr);
2042 STMT_VINFO_DATA_REF (stmt_info) = dr;
2050 /* Utility functions used by vect_mark_stmts_to_be_vectorized. */
2052 /* Function vect_mark_relevant.
2054 Mark STMT as "relevant for vectorization" and add it to WORKLIST. */
2057 vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt)
2059 stmt_vec_info stmt_info;
2061 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2062 fprintf (vect_dump, "mark relevant.");
2064 if (TREE_CODE (stmt) == PHI_NODE)
2066 VEC_safe_push (tree, heap, *worklist, stmt);
2070 stmt_info = vinfo_for_stmt (stmt);
2074 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2076 fprintf (vect_dump, "mark relevant: no stmt info!!.");
2077 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2082 if (STMT_VINFO_RELEVANT_P (stmt_info))
2084 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2085 fprintf (vect_dump, "already marked relevant.");
2089 STMT_VINFO_RELEVANT_P (stmt_info) = 1;
2090 VEC_safe_push (tree, heap, *worklist, stmt);
2094 /* Function vect_stmt_relevant_p.
2096 Return true if STMT in loop that is represented by LOOP_VINFO is
2097 "relevant for vectorization".
2099 A stmt is considered "relevant for vectorization" if:
2100 - it has uses outside the loop.
2101 - it has vdefs (it alters memory).
2102 - control stmts in the loop (except for the exit condition).
2104 CHECKME: what other side effects would the vectorizer allow? */
2107 vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo)
2109 v_may_def_optype v_may_defs;
2110 v_must_def_optype v_must_defs;
2111 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2112 ssa_op_iter op_iter;
2113 imm_use_iterator imm_iter;
2114 use_operand_p use_p;
2117 /* cond stmt other than loop exit cond. */
2118 if (is_ctrl_stmt (stmt) && (stmt != LOOP_VINFO_EXIT_COND (loop_vinfo)))
2121 /* changing memory. */
2122 if (TREE_CODE (stmt) == PHI_NODE)
2124 if (!is_gimple_reg (PHI_RESULT (stmt)))
2126 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, PHI_RESULT (stmt))
2128 basic_block bb = bb_for_stmt (USE_STMT (use_p));
2129 if (!flow_bb_inside_loop_p (loop, bb))
2131 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2132 fprintf (vect_dump, "vec_stmt_relevant_p: used out of loop.");
2139 v_may_defs = STMT_V_MAY_DEF_OPS (stmt);
2140 v_must_defs = STMT_V_MUST_DEF_OPS (stmt);
2141 if (v_may_defs || v_must_defs)
2143 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2144 fprintf (vect_dump, "vec_stmt_relevant_p: stmt has vdefs.");
2148 /* uses outside the loop. */
2149 FOR_EACH_SSA_TREE_OPERAND (var, stmt, op_iter, SSA_OP_DEF)
2151 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
2153 basic_block bb = bb_for_stmt (USE_STMT (use_p));
2154 if (!flow_bb_inside_loop_p (loop, bb))
2156 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2157 fprintf (vect_dump, "vec_stmt_relevant_p: used out of loop.");
2167 /* Function vect_mark_stmts_to_be_vectorized.
2169 Not all stmts in the loop need to be vectorized. For example:
2178 Stmt 1 and 3 do not need to be vectorized, because loop control and
2179 addressing of vectorized data-refs are handled differently.
2181 This pass detects such stmts. */
2184 vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo)
2186 VEC(tree,heap) *worklist;
2187 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2188 basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
2189 unsigned int nbbs = loop->num_nodes;
2190 block_stmt_iterator si;
2196 stmt_vec_info stmt_info;
2200 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2201 fprintf (vect_dump, "=== vect_mark_stmts_to_be_vectorized ===");
2204 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
2206 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2208 fprintf (vect_dump, "init: phi relevant? ");
2209 print_generic_expr (vect_dump, phi, TDF_SLIM);
2212 if (vect_stmt_relevant_p (phi, loop_vinfo))
2214 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2215 LOOP_LOC (loop_vinfo)))
2216 fprintf (vect_dump, "unsupported reduction/induction.");
2221 worklist = VEC_alloc (tree, heap, 64);
2223 /* 1. Init worklist. */
2225 for (i = 0; i < nbbs; i++)
2228 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
2230 stmt = bsi_stmt (si);
2232 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2234 fprintf (vect_dump, "init: stmt relevant? ");
2235 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2238 stmt_info = vinfo_for_stmt (stmt);
2239 STMT_VINFO_RELEVANT_P (stmt_info) = 0;
2241 if (vect_stmt_relevant_p (stmt, loop_vinfo))
2242 vect_mark_relevant (&worklist, stmt);
2247 /* 2. Process_worklist */
2249 while (VEC_length (tree, worklist) > 0)
2251 stmt = VEC_pop (tree, worklist);
2253 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2255 fprintf (vect_dump, "worklist: examine stmt: ");
2256 print_generic_expr (vect_dump, stmt, TDF_SLIM);
2259 /* Examine the USES in this statement. Mark all the statements which
2260 feed this statement's uses as "relevant", unless the USE is used as
2263 if (TREE_CODE (stmt) == PHI_NODE)
2265 /* follow the def-use chain inside the loop. */
2266 for (j = 0; j < PHI_NUM_ARGS (stmt); j++)
2268 tree arg = PHI_ARG_DEF (stmt, j);
2269 tree def_stmt = NULL_TREE;
2271 if (!vect_is_simple_use (arg, loop_vinfo, &def_stmt))
2273 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2274 LOOP_LOC (loop_vinfo)))
2275 fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
2276 VEC_free (tree, heap, worklist);
2282 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2284 fprintf (vect_dump, "worklist: def_stmt: ");
2285 print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
2288 bb = bb_for_stmt (def_stmt);
2289 if (flow_bb_inside_loop_p (loop, bb))
2290 vect_mark_relevant (&worklist, def_stmt);
2294 ann = stmt_ann (stmt);
2295 use_ops = USE_OPS (ann);
2297 for (i = 0; i < NUM_USES (use_ops); i++)
2299 tree use = USE_OP (use_ops, i);
2301 /* We are only interested in uses that need to be vectorized. Uses
2302 that are used for address computation are not considered relevant.
2304 if (exist_non_indexing_operands_for_use_p (use, stmt))
2306 tree def_stmt = NULL_TREE;
2308 if (!vect_is_simple_use (use, loop_vinfo, &def_stmt))
2310 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS,
2311 LOOP_LOC (loop_vinfo)))
2312 fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
2313 VEC_free (tree, heap, worklist);
2320 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2322 fprintf (vect_dump, "worklist: examine use %d: ", i);
2323 print_generic_expr (vect_dump, use, TDF_SLIM);
2326 bb = bb_for_stmt (def_stmt);
2327 if (flow_bb_inside_loop_p (loop, bb))
2328 vect_mark_relevant (&worklist, def_stmt);
2331 } /* while worklist */
2333 VEC_free (tree, heap, worklist);
2338 /* Function vect_can_advance_ivs_p
2340 In case the number of iterations that LOOP iterates in unknown at compile
2341 time, an epilog loop will be generated, and the loop induction variables
2342 (IVs) will be "advanced" to the value they are supposed to take just before
2343 the epilog loop. Here we check that the access function of the loop IVs
2344 and the expression that represents the loop bound are simple enough.
2345 These restrictions will be relaxed in the future. */
2348 vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
2350 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2351 basic_block bb = loop->header;
2354 /* Analyze phi functions of the loop header. */
2356 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
2358 tree access_fn = NULL;
2359 tree evolution_part;
2361 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2363 fprintf (vect_dump, "Analyze phi: ");
2364 print_generic_expr (vect_dump, phi, TDF_SLIM);
2367 /* Skip virtual phi's. The data dependences that are associated with
2368 virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
2370 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
2372 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2373 fprintf (vect_dump, "virtual phi. skip.");
2377 /* Analyze the evolution function. */
2379 access_fn = instantiate_parameters
2380 (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi)));
2384 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2385 fprintf (vect_dump, "No Access function.");
2389 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2391 fprintf (vect_dump, "Access function of PHI: ");
2392 print_generic_expr (vect_dump, access_fn, TDF_SLIM);
2395 evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
2397 if (evolution_part == NULL_TREE)
2400 /* FORNOW: We do not transform initial conditions of IVs
2401 which evolution functions are a polynomial of degree >= 2. */
2403 if (tree_is_chrec (evolution_part))
2411 /* Function vect_get_loop_niters.
2413 Determine how many iterations the loop is executed.
2414 If an expression that represents the number of iterations
2415 can be constructed, place it in NUMBER_OF_ITERATIONS.
2416 Return the loop exit condition. */
2419 vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
2423 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2424 fprintf (vect_dump, "=== get_loop_niters ===");
2426 niters = number_of_iterations_in_loop (loop);
2428 if (niters != NULL_TREE
2429 && niters != chrec_dont_know)
2431 *number_of_iterations = niters;
2433 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2435 fprintf (vect_dump, "==> get_loop_niters:" );
2436 print_generic_expr (vect_dump, *number_of_iterations, TDF_SLIM);
2440 return get_loop_exit_condition (loop);
2444 /* Function vect_analyze_loop_form.
2446 Verify the following restrictions (some may be relaxed in the future):
2447 - it's an inner-most loop
2448 - number of BBs = 2 (which are the loop header and the latch)
2449 - the loop has a pre-header
2450 - the loop has a single entry and exit
2451 - the loop exit condition is simple enough, and the number of iterations
2452 can be analyzed (a countable loop). */
2454 static loop_vec_info
2455 vect_analyze_loop_form (struct loop *loop)
2457 loop_vec_info loop_vinfo;
2459 tree number_of_iterations = NULL;
2462 loop_loc = find_loop_location (loop);
2464 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2465 fprintf (vect_dump, "=== vect_analyze_loop_form ===");
2469 if (vect_print_dump_info (REPORT_OUTER_LOOPS, loop_loc))
2470 fprintf (vect_dump, "not vectorized: nested loop.");
2474 if (!loop->single_exit
2475 || loop->num_nodes != 2
2476 || EDGE_COUNT (loop->header->preds) != 2)
2478 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2480 if (!loop->single_exit)
2481 fprintf (vect_dump, "not vectorized: multiple exits.");
2482 else if (loop->num_nodes != 2)
2483 fprintf (vect_dump, "not vectorized: too many BBs in loop.");
2484 else if (EDGE_COUNT (loop->header->preds) != 2)
2485 fprintf (vect_dump, "not vectorized: too many incoming edges.");
2491 /* We assume that the loop exit condition is at the end of the loop. i.e,
2492 that the loop is represented as a do-while (with a proper if-guard
2493 before the loop if needed), where the loop header contains all the
2494 executable statements, and the latch is empty. */
2495 if (!empty_block_p (loop->latch))
2497 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2498 fprintf (vect_dump, "not vectorized: unexpectd loop form.");
2502 /* Make sure there exists a single-predecessor exit bb: */
2503 if (!single_pred_p (loop->single_exit->dest))
2505 edge e = loop->single_exit;
2506 if (!(e->flags & EDGE_ABNORMAL))
2508 split_loop_exit_edge (e);
2509 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2510 fprintf (vect_dump, "split exit edge.");
2514 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2515 fprintf (vect_dump, "not vectorized: abnormal loop exit edge.");
2520 if (empty_block_p (loop->header))
2522 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2523 fprintf (vect_dump, "not vectorized: empty loop.");
2527 loop_cond = vect_get_loop_niters (loop, &number_of_iterations);
2530 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2531 fprintf (vect_dump, "not vectorized: complicated exit condition.");
2535 if (!number_of_iterations)
2537 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2539 "not vectorized: number of iterations cannot be computed.");
2543 if (chrec_contains_undetermined (number_of_iterations))
2545 if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS, loop_loc))
2546 fprintf (vect_dump, "Infinite number of iterations.");
2550 loop_vinfo = new_loop_vec_info (loop);
2551 LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
2553 if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
2555 if (vect_print_dump_info (REPORT_DETAILS, loop_loc))
2557 fprintf (vect_dump, "Symbolic number of iterations is ");
2558 print_generic_expr (vect_dump, number_of_iterations, TDF_DETAILS);
2562 if (LOOP_VINFO_INT_NITERS (loop_vinfo) == 0)
2564 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS, loop_loc))
2565 fprintf (vect_dump, "not vectorized: number of iterations = 0.");
2569 LOOP_VINFO_EXIT_COND (loop_vinfo) = loop_cond;
2570 LOOP_VINFO_LOC (loop_vinfo) = loop_loc;
2576 /* Function vect_analyze_loop.
2578 Apply a set of analyses on LOOP, and create a loop_vec_info struct
2579 for it. The different analyses will record information in the
2580 loop_vec_info struct. */
2582 vect_analyze_loop (struct loop *loop)
2585 loop_vec_info loop_vinfo;
2587 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2588 fprintf (vect_dump, "===== analyze_loop_nest =====");
2590 /* Check the CFG characteristics of the loop (nesting, entry/exit, etc. */
2592 loop_vinfo = vect_analyze_loop_form (loop);
2595 if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2596 fprintf (vect_dump, "bad loop form.");
2600 /* Find all data references in the loop (which correspond to vdefs/vuses)
2601 and analyze their evolution in the loop.
2603 FORNOW: Handle only simple, array references, which
2604 alignment can be forced, and aligned pointer-references. */
2606 ok = vect_analyze_data_refs (loop_vinfo);
2609 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2610 fprintf (vect_dump, "bad data references.");
2611 destroy_loop_vec_info (loop_vinfo);
2615 /* Data-flow analysis to detect stmts that do not need to be vectorized. */
2617 ok = vect_mark_stmts_to_be_vectorized (loop_vinfo);
2620 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2621 fprintf (vect_dump, "unexpected pattern.");
2622 destroy_loop_vec_info (loop_vinfo);
2626 /* Check that all cross-iteration scalar data-flow cycles are OK.
2627 Cross-iteration cycles caused by virtual phis are analyzed separately. */
2629 ok = vect_analyze_scalar_cycles (loop_vinfo);
2632 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2633 fprintf (vect_dump, "bad scalar cycle.");
2634 destroy_loop_vec_info (loop_vinfo);
2638 ok = vect_determine_vectorization_factor (loop_vinfo);
2641 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2642 fprintf (vect_dump, "can't determine vectorization factor.");
2643 destroy_loop_vec_info (loop_vinfo);
2647 /* Analyze data dependences between the data-refs in the loop.
2648 FORNOW: fail at the first data dependence that we encounter. */
2650 ok = vect_analyze_data_ref_dependences (loop_vinfo);
2653 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2654 fprintf (vect_dump, "bad data dependence.");
2655 destroy_loop_vec_info (loop_vinfo);
2659 /* Analyze the access patterns of the data-refs in the loop (consecutive,
2660 complex, etc.). FORNOW: Only handle consecutive access pattern. */
2662 ok = vect_analyze_data_ref_accesses (loop_vinfo);
2665 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2666 fprintf (vect_dump, "bad data access.");
2667 destroy_loop_vec_info (loop_vinfo);
2671 /* Analyze the alignment of the data-refs in the loop.
2672 FORNOW: Only aligned accesses are handled. */
2674 ok = vect_analyze_data_refs_alignment (loop_vinfo);
2677 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2678 fprintf (vect_dump, "bad data alignment.");
2679 destroy_loop_vec_info (loop_vinfo);
2683 /* Scan all the operations in the loop and make sure they are
2686 ok = vect_analyze_operations (loop_vinfo);
2689 if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
2690 fprintf (vect_dump, "bad operation or unsupported loop bound.");
2691 destroy_loop_vec_info (loop_vinfo);
2695 LOOP_VINFO_VECTORIZABLE_P (loop_vinfo) = 1;