| blob | c718e0742127284762526bcc17542349d737cedf |
1 /* Transformation Utilities for Loop Vectorization.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
3 Contributed by Dorit Naishlos <dorit@il.ibm.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
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
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
48 /* Utility functions for the code transformation. */
51 static tree vect_create_data_ref_ptr
53 static tree vect_create_addr_base_for_vector_ref
58 static void vect_finish_stmt_generation
64 /* Utility function dealing with loop peeling (not peeling itself). */
65 static void vect_generate_tmps_on_preheader
75 static int
77 {
81 {
99 }
100 }
103 /* Function vect_estimate_min_profitable_iters
105 Return the number of iterations required for the vector version of the
106 loop to be profitable relative to the cost of the scalar version of the
107 loop.
109 TODO: Take profile info into account before making vectorization
110 decisions, if available. */
112 int
114 {
130 slp_instance instance;
132 /* Cost model disabled. */
134 {
138 }
140 /* Requires loop versioning tests to handle misalignment. */
143 {
144 /* FIXME: Make cost depend on complexity of individual check. */
145 vec_outside_cost +=
150 }
153 {
154 /* FIXME: Make cost depend on complexity of individual check. */
155 vec_outside_cost +=
160 }
164 {
166 }
168 /* Count statements in scalar loop. Using this as scalar cost for a single
169 iteration for now.
171 TODO: Add outer loop support.
173 TODO: Consider assigning different costs to different scalar
174 statements. */
176 /* FORNOW. */
181 {
182 block_stmt_iterator si;
187 else
191 {
199 /* FIXME: for stmts in the inner-loop in outer-loop vectorization,
200 some of the "outside" costs are generated inside the outer-loop. */
202 }
203 }
205 /* Add additional cost for the peeled instructions in prologue and epilogue
206 loop.
208 FORNOW: If we dont know the value of peel_iters for prologue or epilogue
209 at compile-time - we assume it's vf/2 (the worst would be vf-1).
211 TODO: Build an expression that represents peel_iters for prologue and
212 epilogue to be used in a run-time test. */
217 {
223 /* If peeling for alignment is unknown, loop bound of main loop becomes
224 unknown. */
228 "epilogue peel iters set to vf/2 because "
231 /* If peeled iterations are unknown, count a taken branch and a not taken
232 branch per peeled loop. Even if scalar loop iterations are known,
233 vector iterations are not known since peeled prologue iterations are
234 not known. Hence guards remain the same. */
238 }
239 else
240 {
242 {
249 }
250 else
254 {
258 "epilogue peel iters set to vf/2 because "
261 /* If peeled iterations are known but number of scalar loop
262 iterations are unknown, count a taken branch per peeled loop. */
265 }
266 else
267 {
272 }
273 }
279 /* Allow targets add additional (outside-of-loop) costs. FORNOW, the only
280 information we provide for the target is whether testing against the
281 threshold involves a runtime test. */
283 {
286 /* If the number of iterations is unknown, or the
287 peeling-for-misalignment amount is unknown, we eill have to generate
288 a runtime test to test the loop count against the threshold. */
292 vec_outside_cost +=
297 }
299 /* Add SLP costs. */
302 {
305 }
307 /* Calculate number of iterations required to make the vector version
308 profitable, relative to the loop bodies only. The following condition
309 must hold true: ((SIC*VF)-VIC)*niters > VOC*VF, where
310 SIC = scalar iteration cost, VIC = vector iteration cost,
311 VOC = vector outside cost and VF = vectorization factor. */
314 {
317 else
318 {
328 min_profitable_iters++;
329 }
330 }
331 /* vector version will never be profitable. */
332 else
333 {
336 "is divisible by scalar iteration cost = %d by a factor "
340 }
343 {
346 vec_inside_cost);
348 vec_outside_cost);
351 peel_iters_prologue);
353 peel_iters_epilogue);
355 min_profitable_iters);
356 }
358 min_profitable_iters =
361 /* Because the condition we create is:
362 if (niters <= min_profitable_iters)
363 then skip the vectorized loop. */
364 min_profitable_iters--;
368 min_profitable_iters);
371 }
374 /* TODO: Close dependency between vect_model_*_cost and vectorizable_*
375 functions. Design better to avoid maintenance issues. */
377 /* Function vect_model_reduction_cost.
379 Models cost for a reduction operation, including the vector ops
380 generated within the strip-mine loop, the initial definition before
381 the loop, and the epilogue code that must be generated. */
383 static void
386 {
389 optab optab;
390 tree vectype;
391 tree orig_stmt;
392 tree reduction_op;
399 /* Cost of reduction op inside loop. */
412 /* Add in cost for initial definition. */
415 /* Determine cost of epilogue code.
417 We have a reduction operator that will reduce the vector in one statement.
418 Also requires scalar extract. */
421 {
424 else
425 {
427 tree bitsize =
434 /* We have a whole vector shift available. */
438 /* Final reduction via vector shifts and the reduction operator. Also
439 requires scalar extract. */
442 else
443 /* Use extracts and reduction op for final reduction. For N elements,
444 we have N extracts and N-1 reduction ops. */
446 }
447 }
455 }
458 /* Function vect_model_induction_cost.
460 Models cost for induction operations. */
462 static void
464 {
465 /* loop cost for vec_loop. */
467 /* prologue cost for vec_init and vec_step. */
474 }
477 /* Function vect_model_simple_cost.
479 Models cost for simple operations, i.e. those that only emit ncopies of a
480 single op. Right now, this does not account for multiple insns that could
481 be generated for the single vector op. We will handle that shortly. */
483 void
486 {
492 /* FORNOW: Assuming maximum 2 args per stmts. */
494 {
497 }
503 /* Set the costs either in STMT_INFO or SLP_NODE (if exists). */
506 }
509 /* Function vect_cost_strided_group_size
511 For strided load or store, return the group_size only if it is the first
512 load or store of a group, else return 1. This ensures that group size is
513 only returned once per group. */
515 static int
517 {
524 }
527 /* Function vect_model_store_cost
529 Models cost for stores. In the case of strided accesses, one access
530 has the overhead of the strided access attributed to it. */
532 void
535 {
542 /* Strided access? */
545 /* Not a strided access. */
546 else
549 /* Is this an access in a group of stores, which provide strided access?
550 If so, add in the cost of the permutes. */
552 {
553 /* Uses a high and low interleave operation for each needed permute. */
559 group_size);
561 }
563 /* Costs of the stores. */
570 /* Set the costs either in STMT_INFO or SLP_NODE (if exists). */
573 }
576 /* Function vect_model_load_cost
578 Models cost for loads. In the case of strided accesses, the last access
579 has the overhead of the strided access attributed to it. Since unaligned
580 accesses are supported for loads, we also account for the costs of the
581 access scheme chosen. */
583 void
586 {
589 tree first_stmt;
593 /* Strided accesses? */
596 {
599 }
600 /* Not a strided access. */
601 else
602 {
605 }
609 /* Is this an access in a group of loads providing strided access?
610 If so, add in the cost of the permutes. */
612 {
613 /* Uses an even and odd extract operations for each needed permute. */
619 group_size);
621 }
623 /* The loads themselves. */
625 {
627 {
634 }
636 {
637 /* Here, we assign an additional cost for the unaligned load. */
645 }
647 {
650 /* FIXME: If the misalignment remains fixed across the iterations of
651 the containing loop, the following cost should be added to the
652 outside costs. */
657 }
659 {
664 /* Unaligned software pipeline has a load of an address, an initial
665 load, and possibly a mask operation to "prime" the loop. However,
666 if this is an access in a group of loads, which provide strided
667 access, then the above cost should only be considered for one
668 access in the group. Inside the loop, there is a load op
669 and a realignment op. */
672 {
676 }
681 }
685 }
691 /* Set the costs either in STMT_INFO or SLP_NODE (if exists). */
694 }
697 /* Function vect_get_new_vect_var.
699 Returns a name for a new variable. The current naming scheme appends the
700 prefix "vect_" or "vect_p" (depending on the value of VAR_KIND) to
701 the name of vectorizer generated variables, and appends that to NAME if
702 provided. */
704 static tree
706 {
708 tree new_vect_var;
711 {
723 }
726 {
730 }
731 else
734 /* Mark vector typed variable as a gimple register variable. */
739 }
742 /* Function vect_create_addr_base_for_vector_ref.
744 Create an expression that computes the address of the first memory location
745 that will be accessed for a data reference.
747 Input:
748 STMT: The statement containing the data reference.
749 NEW_STMT_LIST: Must be initialized to NULL_TREE or a statement list.
750 OFFSET: Optional. If supplied, it is be added to the initial address.
751 LOOP: Specify relative to which loop-nest should the address be computed.
752 For example, when the dataref is in an inner-loop nested in an
753 outer-loop that is now being vectorized, LOOP can be either the
754 outer-loop, or the inner-loop. The first memory location accessed
755 by the following dataref ('in' points to short):
757 for (i=0; i<N; i++)
758 for (j=0; j<M; j++)
759 s += in[i+j]
761 is as follows:
762 if LOOP=i_loop: &in (relative to i_loop)
763 if LOOP=j_loop: &in+i*2B (relative to j_loop)
765 Output:
766 1. Return an SSA_NAME whose value is the address of the memory location of
767 the first vector of the data reference.
768 2. If new_stmt_list is not NULL_TREE after return then the caller must insert
769 these statement(s) which define the returned SSA_NAME.
771 FORNOW: We are only handling array accesses with step 1. */
773 static tree
776 tree offset,
778 {
783 tree base_name;
784 tree data_ref_base_var;
785 tree new_base_stmt;
786 tree vec_stmt;
796 {
805 }
807 /* Create data_ref_base */
815 /* Create base_offset */
824 {
833 }
835 /* base + base_offset */
841 /* addr_expr = addr_base */
853 {
856 }
858 }
861 /* Function vect_create_data_ref_ptr.
863 Create a new pointer to vector type (vp), that points to the first location
864 accessed in the loop by STMT, along with the def-use update chain to
865 appropriately advance the pointer through the loop iterations. Also set
866 aliasing information for the pointer. This vector pointer is used by the
867 callers to this function to create a memory reference expression for vector
868 load/store access.
870 Input:
871 1. STMT: a stmt that references memory. Expected to be of the form
872 GIMPLE_MODIFY_STMT <name, data-ref> or
873 GIMPLE_MODIFY_STMT <data-ref, name>.
874 2. AT_LOOP: the loop where the vector memref is to be created.
875 3. OFFSET (optional): an offset to be added to the initial address accessed
876 by the data-ref in STMT.
877 4. ONLY_INIT: indicate if vp is to be updated in the loop, or remain
878 pointing to the initial address.
879 5. TYPE: if not NULL indicates the required type of the data-ref
881 Output:
882 1. Declare a new ptr to vector_type, and have it point to the base of the
883 data reference (initial addressed accessed by the data reference).
884 For example, for vector of type V8HI, the following code is generated:
886 v8hi *vp;
887 vp = (v8hi *)initial_address;
889 if OFFSET is not supplied:
890 initial_address = &a[init];
891 if OFFSET is supplied:
892 initial_address = &a[init + OFFSET];
894 Return the initial_address in INITIAL_ADDRESS.
896 2. If ONLY_INIT is true, just return the initial pointer. Otherwise, also
897 update the pointer in each iteration of the loop.
899 Return the increment stmt that updates the pointer in PTR_INCR.
901 3. Set INV_P to true if the access pattern of the data reference in the
902 vectorized loop is invariant. Set it to false otherwise.
904 4. Return the pointer. */
906 static tree
910 {
911 tree base_name;
918 tree vect_ptr_type;
919 tree vect_ptr;
920 tree tag;
921 tree new_temp;
922 tree vec_stmt;
924 edge pe;
925 basic_block new_bb;
926 tree vect_ptr_init;
928 tree vptr;
929 block_stmt_iterator incr_bsi;
932 tree incr;
933 tree step;
935 /* Check the step (evolution) of the load in LOOP, and record
936 whether it's invariant. */
939 else
944 else
947 /* Create an expression for the first address accessed by this load
948 in LOOP. */
952 {
965 }
967 /** (1) Create the new vector-pointer variable: **/
970 else
976 /** (2) Add aliasing information to the new vector-pointer:
977 (The points-to info (DR_PTR_INFO) may be defined later.) **/
982 /* If tag is a variable (and NOT_A_TAG) than a new symbol memory
983 tag must be created with tag added to its may alias list. */
986 else
991 /** Note: If the dataref is in an inner-loop nested in LOOP, and we are
992 vectorizing LOOP (i.e. outer-loop vectorization), we need to create two
993 def-use update cycles for the pointer: One relative to the outer-loop
994 (LOOP), which is what steps (3) and (4) below do. The other is relative
995 to the inner-loop (which is the inner-most loop containing the dataref),
996 and this is done be step (5) below.
998 When vectorizing inner-most loops, the vectorized loop (LOOP) is also the
999 inner-most loop, and so steps (3),(4) work the same, and step (5) is
1000 redundant. Steps (3),(4) create the following:
1002 vp0 = &base_addr;
1003 LOOP: vp1 = phi(vp0,vp2)
1004 ...
1005 ...
1006 vp2 = vp1 + step
1007 goto LOOP
1009 If there is an inner-loop nested in loop, then step (5) will also be
1010 applied, and an additional update in the inner-loop will be created:
1012 vp0 = &base_addr;
1013 LOOP: vp1 = phi(vp0,vp2)
1014 ...
1015 inner: vp3 = phi(vp1,vp4)
1016 vp4 = vp3 + inner_step
1017 if () goto inner
1018 ...
1019 vp2 = vp1 + step
1020 if () goto LOOP */
1022 /** (3) Calculate the initial address the vector-pointer, and set
1023 the vector-pointer to point to it before the loop: **/
1025 /* Create: (&(base[init_val+offset]) in the loop preheader. */
1034 /* Create: p = (vectype *) initial_base */
1043 /** (4) Handle the updating of the vector-pointer inside the loop.
1044 This is needed when ONLY_INIT is false, and also when AT_LOOP
1045 is the inner-loop nested in LOOP (during outer-loop vectorization).
1046 **/
1049 {
1050 /* Copy the points-to information if it exists. */
1054 }
1055 else
1056 {
1057 /* The step of the vector pointer is the Vector Size. */
1059 /* One exception to the above is when the scalar step of the load in
1060 LOOP is zero. In this case the step here is also zero. */
1074 /* Copy the points-to information if it exists. */
1076 {
1079 }
1086 }
1092 /** (5) Handle the updating of the vector-pointer inside the inner-loop
1093 nested in LOOP, if exists: **/
1097 {
1106 /* Copy the points-to information if it exists. */
1108 {
1111 }
1118 }
1119 else
1121 }
1124 /* Function bump_vector_ptr
1126 Increment a pointer (to a vector type) by vector-size. If requested,
1127 i.e. if PTR-INCR is given, then also connect the new increment stmt
1128 to the existing def-use update-chain of the pointer, by modifying
1129 the PTR_INCR as illustrated below:
1131 The pointer def-use update-chain before this function:
1132 DATAREF_PTR = phi (p_0, p_2)
1133 ....
1134 PTR_INCR: p_2 = DATAREF_PTR + step
1136 The pointer def-use update-chain after this function:
1137 DATAREF_PTR = phi (p_0, p_2)
1138 ....
1139 NEW_DATAREF_PTR = DATAREF_PTR + BUMP
1140 ....
1141 PTR_INCR: p_2 = NEW_DATAREF_PTR + step
1143 Input:
1144 DATAREF_PTR - ssa_name of a pointer (to vector type) that is being updated
1145 in the loop.
1146 PTR_INCR - optional. The stmt that updates the pointer in each iteration of
1147 the loop. The increment amount across iterations is expected
1148 to be vector_size.
1149 BSI - location where the new update stmt is to be placed.
1150 STMT - the original scalar memory-access stmt that is being vectorized.
1151 BUMP - optional. The offset by which to bump the pointer. If not given,
1152 the offset is assumed to be vector_size.
1154 Output: Return NEW_DATAREF_PTR as illustrated above.
1156 */
1158 static tree
1161 {
1168 tree incr_stmt;
1169 ssa_op_iter iter;
1170 use_operand_p use_p;
1171 tree new_dataref_ptr;
1183 /* Copy the points-to information if it exists. */
1191 /* Update the vector-pointer's cross-iteration increment. */
1193 {
1198 else
1200 }
1203 }
1206 /* Function vect_create_destination_var.
1208 Create a new temporary of type VECTYPE. */
1210 static tree
1212 {
1213 tree vec_dest;
1215 tree type;
1230 }
1233 /* Function vect_init_vector.
1235 Insert a new stmt (INIT_STMT) that initializes a new vector variable with
1236 the vector elements of VECTOR_VAR. Place the initialization at BSI if it
1237 is not NULL. Otherwise, place the initialization at the loop preheader.
1238 Return the DEF of INIT_STMT.
1239 It will be used in the vectorization of STMT. */
1241 static tree
1244 {
1246 tree new_var;
1247 tree init_stmt;
1248 tree vec_oprnd;
1249 edge pe;
1250 tree new_temp;
1251 basic_block new_bb;
1261 else
1262 {
1271 }
1274 {
1277 }
1281 }
1284 /* For constant and loop invariant defs of SLP_NODE this function returns
1285 (vector) defs (VEC_OPRNDS) that will be used in the vectorized stmts.
1286 OP_NUM determines if we gather defs for operand 0 or operand 1 of the scalar
1287 stmts. */
1289 static void
1292 {
1298 tree vec_cst;
1301 tree vector_type;
1313 /* NUMBER_OF_COPIES is the number of times we need to use the same values in
1314 created vectors. It is greater than 1 if unrolling is performed.
1316 For example, we have two scalar operands, s1 and s2 (e.g., group of
1317 strided accesses of size two), while NUINTS is four (i.e., four scalars
1318 of this type can be packed in a vector). The output vector will contain
1319 two copies of each scalar operand: {s1, s2, s1, s2}. (NUMBER_OF_COPIES
1320 will be 2).
1322 If GROUP_SIZE > NUNITS, the scalars will be split into several vectors
1323 containing the operands.
1325 For example, NUINTS is four as before, and the group size is 8
1326 (s1, s2, ..., s8). We will create two vectors {s1, s2, s3, s4} and
1327 {s5, s6, s7, s8}. */
1333 {
1335 {
1339 else
1342 /* Create 'vect_ = {op0,op1,...,opn}'. */
1345 number_of_places_left_in_vector--;
1348 {
1355 NULL));
1357 }
1358 }
1359 }
1361 /* Since the vectors are created in the reverse order, we should invert
1362 them. */
1365 {
1368 }
1372 /* In case that VF is greater than the unrolling factor needed for the SLP
1373 group of stmts, NUMBER_OF_VECTORS to be created is greater than
1374 NUMBER_OF_SCALARS/NUNITS or NUNITS/NUMBER_OF_SCALARS, and hence we have
1375 to replicate the vectors. */
1377 {
1380 }
1381 }
1384 /* Get vectorized definitions from SLP_NODE that contains corresponding
1385 vectorized def-stmts. */
1387 static void
1389 {
1390 tree vec_oprnd;
1391 tree vec_def_stmt;
1398 i++)
1399 {
1403 }
1404 }
1407 /* Get vectorized definitions for SLP_NODE.
1408 If the scalar definitions are loop invariants or constants, collect them and
1409 call vect_get_constant_vectors() to create vector stmts.
1410 Otherwise, the def-stmts must be already vectorized and the vectorized stmts
1411 must be stored in the LEFT/RIGHT node of SLP_NODE, and we call
1412 vect_get_slp_vect_defs() to retrieve them.
1413 If VEC_OPRNDS1 is NULL, don't get vector defs for the second operand (from
1414 the right node. This is used when the second operand must remain scalar. */
1416 static void
1419 {
1422 /* Allocate memory for vectorized defs. */
1426 /* SLP_NODE corresponds either to a group of stores or to a group of
1427 unary/binary operations. We don't call this function for loads. */
1429 /* The defs are already vectorized. */
1431 else
1432 /* Build vectors from scalar defs. */
1437 /* Since we don't call this function with loads, this is a group of
1438 stores. */
1449 /* The defs are already vectorized. */
1451 else
1452 /* Build vectors from scalar defs. */
1454 }
1457 /* Function get_initial_def_for_induction
1459 Input:
1460 STMT - a stmt that performs an induction operation in the loop.
1461 IV_PHI - the initial value of the induction variable
1463 Output:
1464 Return a vector variable, initialized with the first VF values of
1465 the induction variable. E.g., for an iv with IV_PHI='X' and
1466 evolution S, for a vector of 4 units, we want to return:
1467 [X, X + S, X + 2*S, X + 3*S]. */
1469 static tree
1471 {
1480 basic_block new_bb;
1482 tree access_fn;
1483 tree new_var;
1484 tree new_name;
1485 tree init_stmt;
1492 tree expr;
1495 tree stmts;
1496 imm_use_iterator imm_iter;
1497 use_operand_p use_p;
1498 tree exit_phi;
1499 edge latch_e;
1500 tree loop_arg;
1501 block_stmt_iterator si;
1507 /* Find the first insertion point in the BB. */
1512 else
1515 /* Is phi in an inner-loop, while vectorizing an enclosing outer-loop? */
1517 {
1520 }
1521 else
1535 /* Create the vector that holds the initial_value of the induction. */
1537 {
1538 /* iv_loop is nested in the loop to be vectorized. init_expr had already
1539 been created during vectorization of previous stmts; We obtain it from
1540 the STMT_VINFO_VEC_STMT of the defining stmt. */
1543 }
1544 else
1545 {
1546 /* iv_loop is the loop to be vectorized. Create:
1547 vec_init = [X, X+S, X+2*S, X+3*S] (S = step_expr, X = init_expr) */
1553 {
1556 }
1561 {
1562 tree tmp;
1564 /* Create: new_name_i = new_name + step_expr */
1574 {
1577 }
1579 }
1580 /* Create a vector from [new_name_0, new_name_1, ..., new_name_nunits-1] */
1583 }
1586 /* Create the vector that holds the step of the induction. */
1588 /* iv_loop is nested in the loop to be vectorized. Generate:
1589 vec_step = [S, S, S, S] */
1591 else
1592 {
1593 /* iv_loop is the loop to be vectorized. Generate:
1594 vec_step = [VF*S, VF*S, VF*S, VF*S] */
1597 }
1606 /* Create the following def-use cycle:
1607 loop prolog:
1608 vec_init = ...
1609 vec_step = ...
1610 loop:
1611 vec_iv = PHI <vec_init, vec_loop>
1612 ...
1613 STMT
1614 ...
1615 vec_loop = vec_iv + vec_step; */
1617 /* Create the induction-phi that defines the induction-operand. */
1625 /* Create the iv update inside the loop */
1635 /* Set the arguments of the phi node: */
1640 /* In case that vectorization factor (VF) is bigger than the number
1641 of elements that we can fit in a vectype (nunits), we have to generate
1642 more than one vector stmt - i.e - we need to "unroll" the
1643 vector stmt by a factor VF/nunits. For more details see documentation
1644 in vectorizable_operation. */
1647 {
1648 stmt_vec_info prev_stmt_vinfo;
1649 /* FORNOW. This restriction should be relaxed. */
1652 /* Create the vector that holds the step of the induction. */
1664 {
1665 tree tmp;
1667 /* vec_i = vec_prev + vec_step */
1677 }
1678 }
1681 {
1682 /* Find the loop-closed exit-phi of the induction, and record
1683 the final vector of induction results: */
1686 {
1688 {
1691 }
1692 }
1694 {
1696 /* FORNOW. Currently not supporting the case that an inner-loop induction
1697 is not used in the outer-loop (i.e. only outside the outer-loop). */
1703 {
1706 }
1707 }
1708 }
1712 {
1717 }
1721 }
1724 /* Function vect_get_vec_def_for_operand.
1726 OP is an operand in STMT. This function returns a (vector) def that will be
1727 used in the vectorized stmt for STMT.
1729 In the case that OP is an SSA_NAME which is defined in the loop, then
1730 STMT_VINFO_VEC_STMT of the defining stmt holds the relevant def.
1732 In case OP is an invariant or constant, a new stmt that creates a vector def
1733 needs to be introduced. */
1735 static tree
1737 {
1738 tree vec_oprnd;
1739 tree vec_stmt;
1740 tree def_stmt;
1746 tree vec_inv;
1747 tree vec_cst;
1749 tree def;
1753 tree vector_type;
1756 {
1759 }
1764 {
1766 {
1769 }
1771 {
1774 }
1775 }
1778 {
1779 /* Case 1: operand is a constant. */
1781 {
1785 /* Create 'vect_cst_ = {cst,cst,...,cst}' */
1790 {
1792 }
1797 }
1799 /* Case 2: operand is defined outside the loop - loop invariant. */
1801 {
1805 /* Create 'vec_inv = {inv,inv,..,inv}' */
1810 {
1812 }
1814 /* FIXME: use build_constructor directly. */
1818 }
1820 /* Case 3: operand is defined inside the loop. */
1822 {
1826 /* Get the def from the vectorized stmt. */
1832 else
1835 }
1837 /* Case 4: operand is defined by a loop header phi - reduction */
1839 {
1845 /* Get the def before the loop */
1848 }
1850 /* Case 5: operand is defined by loop-header phi - induction. */
1852 {
1855 /* Get the def from the vectorized stmt. */
1861 }
1865 }
1866 }
1869 /* Function vect_get_vec_def_for_stmt_copy
1871 Return a vector-def for an operand. This function is used when the
1872 vectorized stmt to be created (by the caller to this function) is a "copy"
1873 created in case the vectorized result cannot fit in one vector, and several
1874 copies of the vector-stmt are required. In this case the vector-def is
1875 retrieved from the vector stmt recorded in the STMT_VINFO_RELATED_STMT field
1876 of the stmt that defines VEC_OPRND.
1877 DT is the type of the vector def VEC_OPRND.
1879 Context:
1880 In case the vectorization factor (VF) is bigger than the number
1881 of elements that can fit in a vectype (nunits), we have to generate
1882 more than one vector stmt to vectorize the scalar stmt. This situation
1883 arises when there are multiple data-types operated upon in the loop; the
1884 smallest data-type determines the VF, and as a result, when vectorizing
1885 stmts operating on wider types we need to create 'VF/nunits' "copies" of the
1886 vector stmt (each computing a vector of 'nunits' results, and together
1887 computing 'VF' results in each iteration). This function is called when
1888 vectorizing such a stmt (e.g. vectorizing S2 in the illustration below, in
1889 which VF=16 and nunits=4, so the number of copies required is 4):
1891 scalar stmt: vectorized into: STMT_VINFO_RELATED_STMT
1893 S1: x = load VS1.0: vx.0 = memref0 VS1.1
1894 VS1.1: vx.1 = memref1 VS1.2
1895 VS1.2: vx.2 = memref2 VS1.3
1896 VS1.3: vx.3 = memref3
1898 S2: z = x + ... VSnew.0: vz0 = vx.0 + ... VSnew.1
1899 VSnew.1: vz1 = vx.1 + ... VSnew.2
1900 VSnew.2: vz2 = vx.2 + ... VSnew.3
1901 VSnew.3: vz3 = vx.3 + ...
1903 The vectorization of S1 is explained in vectorizable_load.
1904 The vectorization of S2:
1905 To create the first vector-stmt out of the 4 copies - VSnew.0 -
1906 the function 'vect_get_vec_def_for_operand' is called to
1907 get the relevant vector-def for each operand of S2. For operand x it
1908 returns the vector-def 'vx.0'.
1910 To create the remaining copies of the vector-stmt (VSnew.j), this
1911 function is called to get the relevant vector-def for each operand. It is
1912 obtained from the respective VS1.j stmt, which is recorded in the
1913 STMT_VINFO_RELATED_STMT field of the stmt that defines VEC_OPRND.
1915 For example, to obtain the vector-def 'vx.1' in order to create the
1916 vector stmt 'VSnew.1', this function is called with VEC_OPRND='vx.0'.
1917 Given 'vx0' we obtain the stmt that defines it ('VS1.0'); from the
1918 STMT_VINFO_RELATED_STMT field of 'VS1.0' we obtain the next copy - 'VS1.1',
1919 and return its def ('vx.1').
1920 Overall, to create the above sequence this function will be called 3 times:
1921 vx.1 = vect_get_vec_def_for_stmt_copy (dt, vx.0);
1922 vx.2 = vect_get_vec_def_for_stmt_copy (dt, vx.1);
1923 vx.3 = vect_get_vec_def_for_stmt_copy (dt, vx.2); */
1925 static tree
1927 {
1928 tree vec_stmt_for_operand;
1929 stmt_vec_info def_stmt_info;
1931 /* Do nothing; can reuse same def. */
1942 }
1945 /* Get vectorized definitions for the operands to create a copy of an original
1946 stmt. See vect_get_vec_def_for_stmt_copy() for details. */
1948 static void
1952 {
1959 {
1963 }
1964 }
1967 /* Get vectorized definitions for OP0 and OP1, or SLP_NODE if it is not NULL. */
1969 static void
1972 {
1975 else
1976 {
1977 tree vec_oprnd;
1984 {
1988 }
1989 }
1990 }
1993 /* Function vect_finish_stmt_generation.
1995 Insert a new stmt. */
1997 static void
2000 {
2013 {
2016 }
2018 /* Make sure bsi points to the stmt that is being vectorized. */
2021 #ifdef USE_MAPPED_LOCATION
2023 #else
2025 #endif
2026 }
2029 /* Function get_initial_def_for_reduction
2031 Input:
2032 STMT - a stmt that performs a reduction operation in the loop.
2033 INIT_VAL - the initial value of the reduction variable
2035 Output:
2036 ADJUSTMENT_DEF - a tree that holds a value to be added to the final result
2037 of the reduction (used for adjusting the epilog - see below).
2038 Return a vector variable, initialized according to the operation that STMT
2039 performs. This vector will be used as the initial value of the
2040 vector of partial results.
2042 Option1 (adjust in epilog): Initialize the vector as follows:
2043 add: [0,0,...,0,0]
2044 mult: [1,1,...,1,1]
2045 min/max: [init_val,init_val,..,init_val,init_val]
2046 bit and/or: [init_val,init_val,..,init_val,init_val]
2047 and when necessary (e.g. add/mult case) let the caller know
2048 that it needs to adjust the result by init_val.
2050 Option2: Initialize the vector as follows:
2051 add: [0,0,...,0,init_val]
2052 mult: [1,1,...,1,init_val]
2053 min/max: [init_val,init_val,...,init_val]
2054 bit and/or: [init_val,init_val,...,init_val]
2055 and no adjustments are needed.
2057 For example, for the following code:
2059 s = init_val;
2060 for (i=0;i<n;i++)
2061 s = s + a[i];
2063 STMT is 's = s + a[i]', and the reduction variable is 's'.
2064 For a vector of 4 units, we want to return either [0,0,0,init_val],
2065 or [0,0,0,0] and let the caller know that it needs to adjust
2066 the result at the end by 'init_val'.
2068 FORNOW, we are using the 'adjust in epilog' scheme, because this way the
2069 initialization vector is simpler (same element in all entries).
2070 A cost model should help decide between these two schemes. */
2072 static tree
2074 {
2082 tree vecdef;
2083 tree def_for_init;
2084 tree init_def;
2087 tree vector_type;
2093 else
2099 {
2105 else
2107 /* Create a vector of zeros for init_def. */
2110 else
2126 }
2129 }
2132 /* Function vect_create_epilog_for_reduction
2134 Create code at the loop-epilog to finalize the result of a reduction
2135 computation.
2137 VECT_DEF is a vector of partial results.
2138 REDUC_CODE is the tree-code for the epilog reduction.
2139 STMT is the scalar reduction stmt that is being vectorized.
2140 REDUCTION_PHI is the phi-node that carries the reduction computation.
2142 This function:
2143 1. Creates the reduction def-use cycle: sets the arguments for
2144 REDUCTION_PHI:
2145 The loop-entry argument is the vectorized initial-value of the reduction.
2146 The loop-latch argument is VECT_DEF - the vector of partial sums.
2147 2. "Reduces" the vector of partial results VECT_DEF into a single result,
2148 by applying the operation specified by REDUC_CODE if available, or by
2149 other means (whole-vector shifts or a scalar loop).
2150 The function also creates a new phi node at the loop exit to preserve
2151 loop-closed form, as illustrated below.
2153 The flow at the entry to this function:
2155 loop:
2156 vec_def = phi <null, null> # REDUCTION_PHI
2157 VECT_DEF = vector_stmt # vectorized form of STMT
2158 s_loop = scalar_stmt # (scalar) STMT
2159 loop_exit:
2160 s_out0 = phi <s_loop> # (scalar) EXIT_PHI
2161 use <s_out0>
2162 use <s_out0>
2164 The above is transformed by this function into:
2166 loop:
2167 vec_def = phi <vec_init, VECT_DEF> # REDUCTION_PHI
2168 VECT_DEF = vector_stmt # vectorized form of STMT
2169 s_loop = scalar_stmt # (scalar) STMT
2170 loop_exit:
2171 s_out0 = phi <s_loop> # (scalar) EXIT_PHI
2172 v_out1 = phi <VECT_DEF> # NEW_EXIT_PHI
2173 v_out2 = reduce <v_out1>
2174 s_out3 = extract_field <v_out2, 0>
2175 s_out4 = adjust_result <s_out3>
2176 use <s_out4>
2177 use <s_out4>
2178 */
2180 static void
2183 {
2185 tree vectype;
2189 basic_block exit_bb;
2190 tree scalar_dest;
2191 tree scalar_type;
2192 tree new_phi;
2193 block_stmt_iterator exit_bsi;
2194 tree vec_dest;
2196 tree new_name;
2201 tree adjustment_def;
2202 tree vec_initial_def;
2203 tree orig_name;
2204 imm_use_iterator imm_iter;
2205 use_operand_p use_p;
2208 tree orig_stmt;
2209 tree use_stmt;
2217 {
2220 }
2227 /*** 1. Create the reduction def-use cycle ***/
2229 /* 1.1 set the loop-entry arg of the reduction-phi: */
2230 /* For the case of reduction, vect_get_vec_def_for_operand returns
2231 the scalar def before the loop, that defines the initial value
2232 of the reduction variable. */
2237 /* 1.2 set the loop-latch arg for the reduction-phi: */
2241 {
2246 }
2249 /*** 2. Create epilog code
2250 The reduction epilog code operates across the elements of the vector
2251 of partial results computed by the vectorized loop.
2252 The reduction epilog code consists of:
2253 step 1: compute the scalar result in a vector (v_out2)
2254 step 2: extract the scalar result (s_out3) from the vector (v_out2)
2255 step 3: adjust the scalar result (s_out3) if needed.
2257 Step 1 can be accomplished using one the following three schemes:
2258 (scheme 1) using reduc_code, if available.
2259 (scheme 2) using whole-vector shifts, if available.
2260 (scheme 3) using a scalar loop. In this case steps 1+2 above are
2261 combined.
2263 The overall epilog code looks like this:
2265 s_out0 = phi <s_loop> # original EXIT_PHI
2266 v_out1 = phi <VECT_DEF> # NEW_EXIT_PHI
2267 v_out2 = reduce <v_out1> # step 1
2268 s_out3 = extract_field <v_out2, 0> # step 2
2269 s_out4 = adjust_result <s_out3> # step 3
2271 (step 3 is optional, and step2 1 and 2 may be combined).
2272 Lastly, the uses of s_out0 are replaced by s_out4.
2274 ***/
2276 /* 2.1 Create new loop-exit-phi to preserve loop-closed form:
2277 v_out1 = phi <v_loop> */
2284 /* 2.2 Get the relevant tree-code to use in the epilog for schemes 2,3
2285 (i.e. when reduc_code is not available) and in the final adjustment
2286 code (if needed). Also get the original scalar reduction variable as
2287 defined in the loop. In case STMT is a "pattern-stmt" (i.e. - it
2288 represents a reduction pattern), the tree-code and scalar-def are
2289 taken from the original stmt that the pattern-stmt (STMT) replaces.
2290 Otherwise (it is a regular reduction) - the tree-code and scalar-def
2291 are taken from STMT. */
2295 {
2296 /* Regular reduction */
2298 }
2299 else
2300 {
2301 /* Reduction pattern */
2305 }
2314 /* In case this is a reduction in an inner-loop while vectorizing an outer
2315 loop - we don't need to extract a single scalar result at the end of the
2316 inner-loop. The final vector of partial results will be used in the
2317 vectorized outer-loop, or reduced to a scalar result at the end of the
2318 outer-loop. */
2322 /* 2.3 Create the reduction code, using one of the three schemes described
2323 above. */
2326 {
2327 tree tmp;
2329 /*** Case 1: Create:
2330 v_out2 = reduc_expr <v_out1> */
2343 }
2344 else
2345 {
2351 tree vec_temp;
2355 else
2358 /* Regardless of whether we have a whole vector shift, if we're
2359 emulating the operation via tree-vect-generic, we don't want
2360 to use it. Only the first round of the reduction is likely
2361 to still be profitable via emulation. */
2362 /* ??? It might be better to emit a reduction tree code here, so that
2363 tree-vect-generic can expand the first round via bit tricks. */
2366 else
2367 {
2371 }
2374 {
2375 /*** Case 2: Create:
2376 for (offset = VS/2; offset >= element_size; offset/=2)
2377 {
2378 Create: va' = vec_shift <va, offset>
2379 Create: va = vop <va, va'>
2380 } */
2391 {
2404 }
2407 }
2408 else
2409 {
2410 tree rhs;
2412 /*** Case 3: Create:
2413 s = extract_field <v_out2, 0>
2414 for (offset = element_size;
2415 offset < vector_size;
2416 offset += element_size;)
2417 {
2418 Create: s' = extract_field <v_out2, offset>
2419 Create: s = op <s, s'>
2420 } */
2428 bitsize_zero_node);
2438 {
2439 tree tmp;
2442 bitpos);
2455 }
2458 }
2459 }
2461 /* 2.4 Extract the final scalar result. Create:
2462 s_out3 = extract_field <v_out2, bitpos> */
2465 {
2466 tree rhs;
2476 else
2485 }
2487 vect_finalize_reduction:
2489 /* 2.5 Adjust the final result by the initial value of the reduction
2490 variable. (When such adjustment is not needed, then
2491 'adjustment_def' is zero). For example, if code is PLUS we create:
2492 new_temp = loop_exit_def + adjustment_def */
2495 {
2497 {
2501 }
2502 else
2503 {
2507 }
2512 }
2515 /* 2.6 Handle the loop-exit phi */
2517 /* Replace uses of s_out0 with uses of s_out3:
2518 Find the loop-closed-use at the loop exit of the original scalar result.
2519 (The reduction result is expected to have two immediate uses - one at the
2520 latch block, and one at the loop exit). */
2523 {
2525 {
2528 }
2529 }
2530 /* We expect to have found an exit_phi because of loop-closed-ssa form. */
2534 {
2536 {
2539 /* FORNOW. Currently not supporting the case that an inner-loop reduction
2540 is not used in the outer-loop (but only outside the outer-loop). */
2549 }
2551 /* Replace the uses: */
2556 }
2558 }
2561 /* Function vectorizable_reduction.
2563 Check if STMT performs a reduction operation that can be vectorized.
2564 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
2565 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
2566 Return FALSE if not a vectorizable STMT, TRUE otherwise.
2568 This function also handles reduction idioms (patterns) that have been
2569 recognized in advance during vect_pattern_recog. In this case, STMT may be
2570 of this form:
2571 X = pattern_expr (arg0, arg1, ..., X)
2572 and it's STMT_VINFO_RELATED_STMT points to the last stmt in the original
2573 sequence that had been detected and replaced by the pattern-stmt (STMT).
2575 In some cases of reduction patterns, the type of the reduction variable X is
2576 different than the type of the other arguments of STMT.
2577 In such cases, the vectype that is used when transforming STMT into a vector
2578 stmt is different than the vectype that is used to determine the
2579 vectorization factor, because it consists of a different number of elements
2580 than the actual number of elements that are being operated upon in parallel.
2582 For example, consider an accumulation of shorts into an int accumulator.
2583 On some targets it's possible to vectorize this pattern operating on 8
2584 shorts at a time (hence, the vectype for purposes of determining the
2585 vectorization factor should be V8HI); on the other hand, the vectype that
2586 is used to create the vector form is actually V4SI (the type of the result).
2588 Upon entry to this function, STMT_VINFO_VECTYPE records the vectype that
2589 indicates what is the actual level of parallelism (V8HI in the example), so
2590 that the right vectorization factor would be derived. This vectype
2591 corresponds to the type of arguments to the reduction stmt, and should *NOT*
2592 be used to create the vectorized stmt. The right vectype for the vectorized
2593 stmt is obtained from the type of the result X:
2594 get_vectype_for_scalar_type (TREE_TYPE (X))
2596 This means that, contrary to "regular" reductions (or "regular" stmts in
2597 general), the following equation:
2598 STMT_VINFO_VECTYPE == get_vectype_for_scalar_type (TREE_TYPE (X))
2599 does *NOT* necessarily hold for reduction patterns. */
2601 bool
2603 {
2604 tree vec_dest;
2605 tree scalar_dest;
2606 tree op;
2612 tree operation;
2620 tree new_phi;
2621 tree scalar_type;
2623 tree orig_stmt;
2624 stmt_vec_info orig_stmt_info;
2629 stmt_vec_info prev_stmt_info;
2630 tree reduc_def;
2635 {
2637 /* FORNOW. This restriction should be relaxed. */
2639 {
2643 }
2644 }
2648 /* FORNOW: SLP not supported. */
2652 /* 1. Is vectorizable reduction? */
2654 /* Not supportable if the reduction variable is used in the loop. */
2658 /* Reductions that are not used even in an enclosing outer-loop,
2659 are expected to be "live" (used out of the loop). */
2664 /* Make sure it was already recognized as a reduction computation. */
2668 /* 2. Has this been recognized as a reduction pattern?
2670 Check if STMT represents a pattern that has been recognized
2671 in earlier analysis stages. For stmts that represent a pattern,
2672 the STMT_VINFO_RELATED_STMT field records the last stmt in
2673 the original sequence that constitutes the pattern. */
2677 {
2682 }
2684 /* 3. Check the operands of the operation. The first operands are defined
2685 inside the loop body. The last operand is the reduction variable,
2686 which is defined by the loop-header-phi. */
2698 /* All uses but the last are expected to be defined in the loop.
2699 The last use is the reduction variable. */
2701 {
2710 }
2719 else
2725 /* 4. Supportable by target? */
2727 /* 4.1. check support for the operation in the loop */
2730 {
2734 }
2737 {
2746 }
2748 /* Worthwhile without SIMD support? */
2752 {
2756 }
2758 /* 4.2. Check support for the epilog operation.
2760 If STMT represents a reduction pattern, then the type of the
2761 reduction variable may be different than the type of the rest
2762 of the arguments. For example, consider the case of accumulation
2763 of shorts into an int accumulator; The original code:
2764 S1: int_a = (int) short_a;
2765 orig_stmt-> S2: int_acc = plus <int_a ,int_acc>;
2767 was replaced with:
2768 STMT: int_acc = widen_sum <short_a, int_acc>
2770 This means that:
2771 1. The tree-code that is used to create the vector operation in the
2772 epilog code (that reduces the partial results) is not the
2773 tree-code of STMT, but is rather the tree-code of the original
2774 stmt from the pattern that STMT is replacing. I.e, in the example
2775 above we want to use 'widen_sum' in the loop, but 'plus' in the
2776 epilog.
2777 2. The type (mode) we use to check available target support
2778 for the vector operation to be created in the *epilog*, is
2779 determined by the type of the reduction variable (in the example
2780 above we'd check this: plus_optab[vect_int_mode]).
2781 However the type (mode) we use to check available target support
2782 for the vector operation to be created *inside the loop*, is
2783 determined by the type of the other arguments to STMT (in the
2784 example we'd check this: widen_sum_optab[vect_short_mode]).
2786 This is contrary to "regular" reductions, in which the types of all
2787 the arguments are the same as the type of the reduction variable.
2788 For "regular" reductions we can therefore use the same vector type
2789 (and also the same tree-code) when generating the epilog code and
2790 when generating the code inside the loop. */
2793 {
2794 /* This is a reduction pattern: get the vectype from the type of the
2795 reduction variable, and get the tree-code from orig_stmt. */
2799 }
2800 else
2801 {
2802 /* Regular reduction: use the same vectype and tree-code as used for
2803 the vector code inside the loop can be used for the epilog code. */
2805 }
2811 {
2815 }
2817 {
2821 }
2824 {
2828 }
2830 /** Transform. **/
2835 /* Create the destination vector */
2838 /* Create the reduction-phi that defines the reduction-operand. */
2841 /* In case the vectorization factor (VF) is bigger than the number
2842 of elements that we can fit in a vectype (nunits), we have to generate
2843 more than one vector stmt - i.e - we need to "unroll" the
2844 vector stmt by a factor VF/nunits. For more details see documentation
2845 in vectorizable_operation. */
2849 {
2850 /* Handle uses. */
2852 {
2856 {
2859 }
2861 /* Get the vector def for the reduction variable from the phi node */
2863 }
2864 else
2865 {
2871 /* Get the vector def for the reduction variable from the vectorized
2872 reduction operation generated in the previous iteration (j-1) */
2874 }
2876 /* Arguments are ready. create the new vector stmt. */
2879 else
2881 reduc_def);
2889 else
2892 }
2894 /* Finalize the reduction-phi (set it's arguments) and create the
2895 epilog reduction code. */
2898 }
2900 /* Checks if CALL can be vectorized in type VECTYPE. Returns
2901 a function declaration if the target has a vectorized version
2902 of the function, or NULL_TREE if the function cannot be vectorized. */
2904 tree
2906 {
2910 /* We only handle functions that do not read or clobber memory -- i.e.
2911 const or novops ones. */
2922 vectype_in);
2923 }
2925 /* Function vectorizable_call.
2927 Check if STMT performs a function call that can be vectorized.
2928 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
2929 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
2930 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
2932 bool
2934 {
2935 tree vec_dest;
2936 tree scalar_dest;
2937 tree operation;
2948 tree new_stmt;
2950 call_expr_arg_iterator iter;
2951 tree vargs;
2960 /* FORNOW: SLP not supported. */
2964 /* FORNOW: not yet supported. */
2966 {
2970 }
2972 /* Is STMT a vectorizable call? */
2983 /* Process function arguments. */
2987 {
2988 /* Bail out if the function has more than two arguments, we
2989 do not have interesting builtin functions to vectorize with
2990 more than two arguments. */
2994 /* We can only handle calls with arguments of the same type. */
2997 {
3001 }
3005 {
3009 }
3012 }
3014 /* No arguments is also not good. */
3029 /* FORNOW */
3036 else
3039 /* For now, we only vectorize functions if a target specific builtin
3040 is available. TODO -- in some cases, it might be profitable to
3041 insert the calls for pieces of the vector, in order to be able
3042 to vectorize other operations in the loop. */
3045 {
3050 }
3056 else
3059 /* Sanity check: make sure that at least one copy of the vectorized stmt
3060 needs to be generated. */
3063 /* FORNOW. This restriction should be relaxed. */
3065 {
3069 }
3072 {
3078 }
3080 /** Transform. **/
3085 /* FORNOW. This restriction should be relaxed. */
3087 {
3091 }
3093 /* Handle def. */
3099 {
3102 {
3103 /* Build argument list for the vectorized call. */
3104 /* FIXME: Rewrite this so that it doesn't
3105 construct a temporary list. */
3109 {
3111 vec_oprnd0
3113 else
3114 vec_oprnd0
3120 }
3132 else
3136 }
3142 {
3143 /* Build argument list for the vectorized call. */
3144 /* FIXME: Rewrite this so that it doesn't
3145 construct a temporary list. */
3149 {
3151 {
3152 vec_oprnd0
3154 vec_oprnd1
3156 }
3157 else
3158 {
3159 vec_oprnd0
3161 vec_oprnd1
3163 }
3169 }
3181 else
3185 }
3192 /* No current target implements this case. */
3194 }
3196 /* The call in STMT might prevent it from being removed in dce.
3197 We however cannot remove it here, due to the way the ssa name
3198 it defines is mapped to the new definition. So just replace
3199 rhs of the statement with something harmless. */
3205 }
3208 /* Function vect_gen_widened_results_half
3210 Create a vector stmt whose code, type, number of arguments, and result
3211 variable are CODE, VECTYPE, OP_TYPE, and VEC_DEST, and its arguments are
3212 VEC_OPRND0 and VEC_OPRND1. The new vector stmt is to be inserted at BSI.
3213 In the case that CODE is a CALL_EXPR, this means that a call to DECL
3214 needs to be created (DECL is a function-decl of a target-builtin).
3215 STMT is the original scalar stmt that we are vectorizing. */
3217 static tree
3221 tree stmt)
3222 {
3223 tree expr;
3224 tree new_stmt;
3225 tree new_temp;
3226 tree sym;
3227 ssa_op_iter iter;
3229 /* Generate half of the widened result: */
3231 {
3232 /* Target specific support */
3235 else
3237 }
3238 else
3239 {
3240 /* Generic support */
3244 else
3246 }
3253 {
3255 {
3259 }
3260 }
3263 }
3266 /* Check if STMT performs a conversion operation, that can be vectorized.
3267 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
3268 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
3269 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
3271 bool
3274 {
3275 tree vec_dest;
3276 tree scalar_dest;
3277 tree operation;
3278 tree op0;
3285 tree new_temp;
3289 stmt_vec_info prev_stmt_info;
3294 tree expr;
3296 tree builtin_decl;
3300 tree vop0;
3302 /* Is STMT a vectorizable conversion? */
3311 {
3312 /* FORNOW: not yet supported. */
3316 }
3329 /* Check types of lhs and rhs. */
3344 /* FORNOW */
3351 else
3357 /* Bail out if the types are both integral or non-integral. */
3364 else
3367 /* FORNOW: SLP with multiple types is not supported. The SLP analysis verifies
3368 this, so we can safely override NCOPIES with 1 here. */
3372 /* Sanity check: make sure that at least one copy of the vectorized stmt
3373 needs to be generated. */
3376 /* FORNOW. This restriction should be relaxed. */
3378 {
3382 }
3384 /* Check the operands of the operation. */
3386 {
3390 }
3392 /* Supportable by target? */
3402 {
3406 }
3409 {
3411 /* FORNOW: SLP not supported. */
3414 }
3417 {
3420 }
3422 /** Transform. **/
3426 /* Handle def. */
3434 {
3437 {
3438 tree sym;
3439 ssa_op_iter iter;
3443 else
3446 builtin_decl =
3449 {
3452 /* Arguments are ready. create the new vector stmt. */
3458 SSA_OP_ALL_VIRTUALS)
3459 {
3463 }
3466 }
3470 else
3473 }
3477 /* In case the vectorization factor (VF) is bigger than the number
3478 of elements that we can fit in a vectype (nunits), we have to
3479 generate more than one vector stmt - i.e - we need to "unroll"
3480 the vector stmt by a factor VF/nunits. */
3482 {
3485 else
3490 /* Generate first half of the widened result: */
3491 new_stmt
3497 else
3501 /* Generate second half of the widened result: */
3502 new_stmt
3508 }
3512 /* In case the vectorization factor (VF) is bigger than the number
3513 of elements that we can fit in a vectype (nunits), we have to
3514 generate more than one vector stmt - i.e - we need to "unroll"
3515 the vector stmt by a factor VF/nunits. */
3517 {
3518 /* Handle uses. */
3520 {
3523 }
3524 else
3525 {
3528 }
3530 /* Arguments are ready. Create the new vector stmt. */
3539 else
3543 }
3546 }
3549 }
3552 /* Function vectorizable_assignment.
3554 Check if STMT performs an assignment (copy) that can be vectorized.
3555 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
3556 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
3557 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
3559 bool
3561 slp_tree slp_node)
3562 {
3563 tree vec_dest;
3564 tree scalar_dest;
3565 tree op;
3569 tree new_temp;
3576 tree vop;
3588 /* FORNOW: not yet supported. */
3590 {
3594 }
3596 /* Is vectorizable assignment? */
3606 {
3610 }
3613 {
3619 }
3621 /** Transform. **/
3625 /* Handle def. */
3628 /* Handle use. */
3631 /* Arguments are ready. create the new vector stmt. */
3633 {
3642 }
3646 }
3649 /* Function vect_min_worthwhile_factor.
3651 For a loop where we could vectorize the operation indicated by CODE,
3652 return the minimum vectorization factor that makes it worthwhile
3653 to use generic vectors. */
3654 static int
3656 {
3658 {
3672 }
3673 }
3676 /* Function vectorizable_induction
3678 Check if PHI performs an induction computation that can be vectorized.
3679 If VEC_STMT is also passed, vectorize the induction PHI: create a vectorized
3680 phi to replace it, put it in VEC_STMT, and add it to the same basic block.
3681 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
3683 bool
3686 {
3692 tree vec_def;
3699 /* FORNOW: SLP not supported. */
3706 {
3707 /* FORNOW: not yet supported. */
3711 }
3717 {
3723 }
3725 /** Transform. **/
3733 }
3736 /* Function vectorizable_operation.
3738 Check if STMT performs a binary or unary operation that can be vectorized.
3739 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
3740 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
3741 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
3743 bool
3745 slp_tree slp_node)
3746 {
3747 tree vec_dest;
3748 tree scalar_dest;
3749 tree operation;
3758 tree new_temp;
3760 optab optab;
3766 stmt_vec_info prev_stmt_info;
3769 tree vectype_out;
3775 /* FORNOW: SLP with multiple types is not supported. The SLP analysis verifies
3776 this, so we can safely override NCOPIES with 1 here. */
3780 /* FORNOW. This restriction should be relaxed. */
3782 {
3786 }
3794 /* FORNOW: not yet supported. */
3796 {
3800 }
3802 /* Is STMT a vectorizable binary/unary operation? */
3820 /* For pointer addition, we should use the normal plus for
3821 the vector addition. */
3827 /* Support only unary or binary operations. */
3830 {
3834 }
3838 {
3842 }
3845 {
3848 {
3852 }
3853 }
3855 /* Supportable by target? */
3857 {
3861 }
3865 {
3874 }
3876 /* Worthwhile without SIMD support? */
3880 {
3884 }
3887 {
3888 /* FORNOW: not yet supported. */
3892 /* Invariant argument is needed for a vector shift
3893 by a scalar shift operand. */
3898 {
3902 }
3903 }
3906 {
3912 }
3914 /** Transform. **/
3919 /* Handle def. */
3927 /* In case the vectorization factor (VF) is bigger than the number
3928 of elements that we can fit in a vectype (nunits), we have to generate
3929 more than one vector stmt - i.e - we need to "unroll" the
3930 vector stmt by a factor VF/nunits. In doing so, we record a pointer
3931 from one copy of the vector stmt to the next, in the field
3932 STMT_VINFO_RELATED_STMT. This is necessary in order to allow following
3933 stages to find the correct vector defs to be used when vectorizing
3934 stmts that use the defs of the current stmt. The example below illustrates
3935 the vectorization process when VF=16 and nunits=4 (i.e - we need to create
3936 4 vectorized stmts):
3938 before vectorization:
3939 RELATED_STMT VEC_STMT
3940 S1: x = memref - -
3941 S2: z = x + 1 - -
3943 step 1: vectorize stmt S1 (done in vectorizable_load. See more details
3944 there):
3945 RELATED_STMT VEC_STMT
3946 VS1_0: vx0 = memref0 VS1_1 -
3947 VS1_1: vx1 = memref1 VS1_2 -
3948 VS1_2: vx2 = memref2 VS1_3 -
3949 VS1_3: vx3 = memref3 - -
3950 S1: x = load - VS1_0
3951 S2: z = x + 1 - -
3953 step2: vectorize stmt S2 (done here):
3954 To vectorize stmt S2 we first need to find the relevant vector
3955 def for the first operand 'x'. This is, as usual, obtained from
3956 the vector stmt recorded in the STMT_VINFO_VEC_STMT of the stmt
3957 that defines 'x' (S1). This way we find the stmt VS1_0, and the
3958 relevant vector def 'vx0'. Having found 'vx0' we can generate
3959 the vector stmt VS2_0, and as usual, record it in the
3960 STMT_VINFO_VEC_STMT of stmt S2.
3961 When creating the second copy (VS2_1), we obtain the relevant vector
3962 def from the vector stmt recorded in the STMT_VINFO_RELATED_STMT of
3963 stmt VS1_0. This way we find the stmt VS1_1 and the relevant
3964 vector def 'vx1'. Using 'vx1' we create stmt VS2_1 and record a
3965 pointer to it in the STMT_VINFO_RELATED_STMT of the vector stmt VS2_0.
3966 Similarly when creating stmts VS2_2 and VS2_3. This is the resulting
3967 chain of stmts and pointers:
3968 RELATED_STMT VEC_STMT
3969 VS1_0: vx0 = memref0 VS1_1 -
3970 VS1_1: vx1 = memref1 VS1_2 -
3971 VS1_2: vx2 = memref2 VS1_3 -
3972 VS1_3: vx3 = memref3 - -
3973 S1: x = load - VS1_0
3974 VS2_0: vz0 = vx0 + v1 VS2_1 -
3975 VS2_1: vz1 = vx1 + v1 VS2_2 -
3976 VS2_2: vz2 = vx2 + v1 VS2_3 -
3977 VS2_3: vz3 = vx3 + v1 - -
3978 S2: z = x + 1 - VS2_0 */
3982 {
3983 /* Handle uses. */
3985 {
3988 {
3989 /* Vector shl and shr insn patterns can be defined with scalar
3990 operand 2 (shift operand). In this case, use constant or loop
3991 invariant op1 directly, without extending it to vector mode
3992 first. */
3995 {
4000 }
4001 }
4003 /* vec_oprnd is available if operand 1 should be of a scalar-type
4004 (a special case for certain kind of vector shifts); otherwise,
4005 operand 1 should be of a vector type (the usual case). */
4008 slp_node);
4009 else
4011 slp_node);
4012 }
4013 else
4016 /* Arguments are ready. Create the new vector stmt. */
4018 {
4020 {
4024 }
4025 else
4034 }
4038 else
4041 }
4048 }
4051 /* Function vectorizable_type_demotion
4053 Check if STMT performs a binary or unary operation that involves
4054 type demotion, and if it can be vectorized.
4055 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
4056 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
4057 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
4059 bool
4062 {
4063 tree vec_dest;
4064 tree scalar_dest;
4065 tree operation;
4066 tree op0;
4072 tree new_temp;
4075 tree new_stmt;
4076 stmt_vec_info prev_stmt_info;
4079 tree vectype_out;
4082 tree expr;
4083 tree vectype_in;
4091 /* FORNOW: not yet supported. */
4093 {
4097 }
4099 /* Is STMT a vectorizable type-demotion operation? */
4127 /* FORNOW. This restriction should be relaxed. */
4129 {
4133 }
4142 /* Check the operands of the operation. */
4144 {
4148 }
4150 /* Supportable by target? */
4157 {
4163 }
4165 /** Transform. **/
4168 ncopies);
4170 /* Handle def. */
4173 /* In case the vectorization factor (VF) is bigger than the number
4174 of elements that we can fit in a vectype (nunits), we have to generate
4175 more than one vector stmt - i.e - we need to "unroll" the
4176 vector stmt by a factor VF/nunits. */
4179 {
4180 /* Handle uses. */
4182 {
4185 }
4186 else
4187 {
4190 }
4192 /* Arguments are ready. Create the new vector stmt. */
4201 else
4205 }
4209 }
4212 /* Function vectorizable_type_promotion
4214 Check if STMT performs a binary or unary operation that involves
4215 type promotion, and if it can be vectorized.
4216 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
4217 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
4218 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
4220 bool
4223 {
4224 tree vec_dest;
4225 tree scalar_dest;
4226 tree operation;
4237 tree new_stmt;
4238 stmt_vec_info prev_stmt_info;
4241 tree vectype_out;
4244 tree vectype_in;
4252 /* FORNOW: not yet supported. */
4254 {
4258 }
4260 /* Is STMT a vectorizable type-promotion operation? */
4289 /* FORNOW. This restriction should be relaxed. */
4291 {
4295 }
4304 /* Check the operands of the operation. */
4306 {
4310 }
4314 {
4317 {
4321 }
4322 }
4324 /* Supportable by target? */
4332 {
4338 }
4340 /** Transform. **/
4344 ncopies);
4346 /* Handle def. */
4349 /* In case the vectorization factor (VF) is bigger than the number
4350 of elements that we can fit in a vectype (nunits), we have to generate
4351 more than one vector stmt - i.e - we need to "unroll" the
4352 vector stmt by a factor VF/nunits. */
4356 {
4357 /* Handle uses. */
4359 {
4363 }
4364 else
4365 {
4369 }
4371 /* Arguments are ready. Create the new vector stmt. We are creating
4372 two vector defs because the widened result does not fit in one vector.
4373 The vectorized stmt can be expressed as a call to a taregt builtin,
4374 or a using a tree-code. */
4375 /* Generate first half of the widened result: */
4380 else
4384 /* Generate second half of the widened result: */
4390 }
4394 }
4397 /* Function vect_strided_store_supported.
4399 Returns TRUE is INTERLEAVE_HIGH and INTERLEAVE_LOW operations are supported,
4400 and FALSE otherwise. */
4402 static bool
4404 {
4410 /* Check that the operation is supported. */
4412 vectype);
4414 vectype);
4416 {
4420 }
4423 == CODE_FOR_nothing
4426 {
4430 }
4433 }
4436 /* Function vect_permute_store_chain.
4438 Given a chain of interleaved stores in DR_CHAIN of LENGTH that must be
4439 a power of 2, generate interleave_high/low stmts to reorder the data
4440 correctly for the stores. Return the final references for stores in
4441 RESULT_CHAIN.
4443 E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8.
4444 The input is 4 vectors each containing 8 elements. We assign a number to each
4445 element, the input sequence is:
4447 1st vec: 0 1 2 3 4 5 6 7
4448 2nd vec: 8 9 10 11 12 13 14 15
4449 3rd vec: 16 17 18 19 20 21 22 23
4450 4th vec: 24 25 26 27 28 29 30 31
4452 The output sequence should be:
4454 1st vec: 0 8 16 24 1 9 17 25
4455 2nd vec: 2 10 18 26 3 11 19 27
4456 3rd vec: 4 12 20 28 5 13 21 30
4457 4th vec: 6 14 22 30 7 15 23 31
4459 i.e., we interleave the contents of the four vectors in their order.
4461 We use interleave_high/low instructions to create such output. The input of
4462 each interleave_high/low operation is two vectors:
4463 1st vec 2nd vec
4464 0 1 2 3 4 5 6 7
4465 the even elements of the result vector are obtained left-to-right from the
4466 high/low elements of the first vector. The odd elements of the result are
4467 obtained left-to-right from the high/low elements of the second vector.
4468 The output of interleave_high will be: 0 4 1 5
4469 and of interleave_low: 2 6 3 7
4472 The permutation is done in log LENGTH stages. In each stage interleave_high
4473 and interleave_low stmts are created for each pair of vectors in DR_CHAIN,
4474 where the first argument is taken from the first half of DR_CHAIN and the
4475 second argument from it's second half.
4476 In our example,
4478 I1: interleave_high (1st vec, 3rd vec)
4479 I2: interleave_low (1st vec, 3rd vec)
4480 I3: interleave_high (2nd vec, 4th vec)
4481 I4: interleave_low (2nd vec, 4th vec)
4483 The output for the first stage is:
4485 I1: 0 16 1 17 2 18 3 19
4486 I2: 4 20 5 21 6 22 7 23
4487 I3: 8 24 9 25 10 26 11 27
4488 I4: 12 28 13 29 14 30 15 31
4490 The output of the second stage, i.e. the final result is:
4492 I1: 0 8 16 24 1 9 17 25
4493 I2: 2 10 18 26 3 11 19 27
4494 I3: 4 12 20 28 5 13 21 30
4495 I4: 6 14 22 30 7 15 23 31. */
4497 static bool
4500 tree stmt,
4503 {
4515 /* Check that the operation is supported. */
4522 {
4524 {
4528 /* Create interleaving stmt:
4529 in the case of big endian:
4530 high = interleave_high (vect1, vect2)
4531 and in the case of little endian:
4532 high = interleave_low (vect1, vect2). */
4538 else
4546 /* Create interleaving stmt:
4547 in the case of big endian:
4548 low = interleave_low (vect1, vect2)
4549 and in the case of little endian:
4550 low = interleave_high (vect1, vect2). */
4556 else
4563 }
4565 }
4567 }
4570 /* Function vectorizable_store.
4572 Check if STMT defines a non scalar data-ref (array/pointer/structure) that
4573 can be vectorized.
4574 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
4575 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
4576 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
4578 bool
4580 slp_tree slp_node)
4581 {
4582 tree scalar_dest;
4583 tree data_ref;
4584 tree op;
4592 tree dummy;
4608 stmt_vec_info first_stmt_vinfo;
4611 /* FORNOW: SLP with multiple types is not supported. The SLP analysis verifies
4612 this, so we can safely override NCOPIES with 1 here. */
4618 /* FORNOW. This restriction should be relaxed. */
4620 {
4624 }
4633 {
4637 }
4639 /* Is vectorizable store? */
4652 {
4656 }
4659 /* FORNOW. In some cases can vectorize even if data-type not supported
4660 (e.g. - array initialization with 0). */
4668 {
4673 }
4676 {
4681 }
4683 /** Transform. **/
4686 {
4693 /* FORNOW */
4696 /* We vectorize all the stmts of the interleaving group when we
4697 reach the last stmt in the group. */
4701 {
4704 }
4709 /* VEC_NUM is the number of vect stmts to be created for this group. */
4712 else
4714 }
4715 else
4716 {
4721 }
4733 /* In case the vectorization factor (VF) is bigger than the number
4734 of elements that we can fit in a vectype (nunits), we have to generate
4735 more than one vector stmt - i.e - we need to "unroll" the
4736 vector stmt by a factor VF/nunits. For more details see documentation in
4737 vect_get_vec_def_for_copy_stmt. */
4739 /* In case of interleaving (non-unit strided access):
4741 S1: &base + 2 = x2
4742 S2: &base = x0
4743 S3: &base + 1 = x1
4744 S4: &base + 3 = x3
4746 We create vectorized stores starting from base address (the access of the
4747 first stmt in the chain (S2 in the above example), when the last store stmt
4748 of the chain (S4) is reached:
4750 VS1: &base = vx2
4751 VS2: &base + vec_size*1 = vx0
4752 VS3: &base + vec_size*2 = vx1
4753 VS4: &base + vec_size*3 = vx3
4755 Then permutation statements are generated:
4757 VS5: vx5 = VEC_INTERLEAVE_HIGH_EXPR < vx0, vx3 >
4758 VS6: vx6 = VEC_INTERLEAVE_LOW_EXPR < vx0, vx3 >
4759 ...
4761 And they are put in STMT_VINFO_VEC_STMT of the corresponding scalar stmts
4762 (the order of the data-refs in the output of vect_permute_store_chain
4763 corresponds to the order of scalar stmts in the interleaving chain - see
4764 the documentation of vect_permute_store_chain()).
4766 In case of both multiple types and interleaving, above vector stores and
4767 permutation stmts are created for every copy. The result vector stmts are
4768 put in STMT_VINFO_VEC_STMT for the first copy and in the corresponding
4769 STMT_VINFO_RELATED_STMT for the next copies.
4770 */
4774 {
4775 tree new_stmt;
4776 tree ptr_incr;
4779 {
4781 {
4782 /* Get vectorized arguments for SLP_NODE. */
4786 }
4787 else
4788 {
4789 /* For interleaved stores we collect vectorized defs for all the
4790 stores in the group in DR_CHAIN and OPRNDS. DR_CHAIN is then
4791 used as an input to vect_permute_store_chain(), and OPRNDS as
4792 an input to vect_get_vec_def_for_stmt_copy() for the next copy.
4794 If the store is not strided, GROUP_SIZE is 1, and DR_CHAIN and
4795 OPRNDS are of size 1. */
4798 {
4799 /* Since gaps are not supported for interleaved stores,
4800 GROUP_SIZE is the exact number of stmts in the chain.
4801 Therefore, NEXT_STMT can't be NULL_TREE. In case that
4802 there is no interleaving, GROUP_SIZE is 1, and only one
4803 iteration of the loop will be executed. */
4808 NULL);
4812 }
4813 }
4818 }
4819 else
4820 {
4821 /* FORNOW SLP doesn't work for multiple types. */
4824 /* For interleaved stores we created vectorized defs for all the
4825 defs stored in OPRNDS in the previous iteration (previous copy).
4826 DR_CHAIN is then used as an input to vect_permute_store_chain(),
4827 and OPRNDS as an input to vect_get_vec_def_for_stmt_copy() for the
4828 next copy.
4829 If the store is not strided, GROUP_SIZE is 1, and DR_CHAIN and
4830 OPRNDS are of size 1. */
4832 {
4837 }
4838 dataref_ptr =
4840 }
4843 {
4845 /* Permute. */
4849 }
4853 {
4855 /* Bump the vector pointer. */
4857 NULL_TREE);
4862 /* For strided stores vectorized defs are interleaved in
4863 vect_permute_store_chain(). */
4867 /* Arguments are ready. Create the new vector stmt. */
4874 else
4881 }
4882 }
4885 }
4888 /* Function vect_setup_realignment
4890 This function is called when vectorizing an unaligned load using
4891 the dr_explicit_realign[_optimized] scheme.
4892 This function generates the following code at the loop prolog:
4894 p = initial_addr;
4895 x msq_init = *(floor(p)); # prolog load
4896 realignment_token = call target_builtin;
4897 loop:
4898 x msq = phi (msq_init, ---)
4900 The stmts marked with x are generated only for the case of
4901 dr_explicit_realign_optimized.
4903 The code above sets up a new (vector) pointer, pointing to the first
4904 location accessed by STMT, and a "floor-aligned" load using that pointer.
4905 It also generates code to compute the "realignment-token" (if the relevant
4906 target hook was defined), and creates a phi-node at the loop-header bb
4907 whose arguments are the result of the prolog-load (created by this
4908 function) and the result of a load that takes place in the loop (to be
4909 created by the caller to this function).
4911 For the case of dr_explicit_realign_optimized:
4912 The caller to this function uses the phi-result (msq) to create the
4913 realignment code inside the loop, and sets up the missing phi argument,
4914 as follows:
4915 loop:
4916 msq = phi (msq_init, lsq)
4917 lsq = *(floor(p')); # load in loop
4918 result = realign_load (msq, lsq, realignment_token);
4920 For the case of dr_explicit_realign:
4921 loop:
4922 msq = *(floor(p)); # load in loop
4923 p' = p + (VS-1);
4924 lsq = *(floor(p')); # load in loop
4925 result = realign_load (msq, lsq, realignment_token);
4927 Input:
4928 STMT - (scalar) load stmt to be vectorized. This load accesses
4929 a memory location that may be unaligned.
4930 BSI - place where new code is to be inserted.
4931 ALIGNMENT_SUPPORT_SCHEME - which of the two misalignment handling schemes
4932 is used.
4934 Output:
4935 REALIGNMENT_TOKEN - the result of a call to the builtin_mask_for_load
4936 target hook, if defined.
4937 Return value - the result of the loop-header phi node. */
4939 static tree
4943 tree init_addr,
4945 {
4950 edge pe;
4952 tree vec_dest;
4953 tree inc;
4954 tree ptr;
4955 tree data_ref;
4956 tree new_stmt;
4957 basic_block new_bb;
4959 tree new_temp;
4960 tree phi_stmt;
4972 /* We need to generate three things:
4973 1. the misalignment computation
4974 2. the extra vector load (for the optimized realignment scheme).
4975 3. the phi node for the two vectors from which the realignment is
4976 done (for the optimized realignment scheme).
4977 */
4979 /* 1. Determine where to generate the misalignment computation.
4981 If INIT_ADDR is NULL_TREE, this indicates that the misalignment
4982 calculation will be generated by this function, outside the loop (in the
4983 preheader). Otherwise, INIT_ADDR had already been computed for us by the
4984 caller, inside the loop.
4986 Background: If the misalignment remains fixed throughout the iterations of
4987 the loop, then both realignment schemes are applicable, and also the
4988 misalignment computation can be done outside LOOP. This is because we are
4989 vectorizing LOOP, and so the memory accesses in LOOP advance in steps that
4990 are a multiple of VS (the Vector Size), and therefore the misalignment in
4991 different vectorized LOOP iterations is always the same.
4992 The problem arises only if the memory access is in an inner-loop nested
4993 inside LOOP, which is now being vectorized using outer-loop vectorization.
4994 This is the only case when the misalignment of the memory access may not
4995 remain fixed throughout the iterations of the inner-loop (as explained in
4996 detail in vect_supportable_dr_alignment). In this case, not only is the
4997 optimized realignment scheme not applicable, but also the misalignment
4998 computation (and generation of the realignment token that is passed to
4999 REALIGN_LOAD) have to be done inside the loop.
5001 In short, INIT_ADDR indicates whether we are in a COMPUTE_IN_LOOP mode
5002 or not, which in turn determines if the misalignment is computed inside
5003 the inner-loop, or outside LOOP. */
5006 {
5009 }
5012 /* 2. Determine where to generate the extra vector load.
5014 For the optimized realignment scheme, instead of generating two vector
5015 loads in each iteration, we generate a single extra vector load in the
5016 preheader of the loop, and in each iteration reuse the result of the
5017 vector load from the previous iteration. In case the memory access is in
5018 an inner-loop nested inside LOOP, which is now being vectorized using
5019 outer-loop vectorization, we need to determine whether this initial vector
5020 load should be generated at the preheader of the inner-loop, or can be
5021 generated at the preheader of LOOP. If the memory access has no evolution
5022 in LOOP, it can be generated in the preheader of LOOP. Otherwise, it has
5023 to be generated inside LOOP (in the preheader of the inner-loop). */
5026 {
5031 }
5032 else
5037 /* 3. For the case of the optimized realignment, create the first vector
5038 load at the loop preheader. */
5041 {
5042 /* Create msq_init = *(floor(p1)) in the loop preheader */
5056 }
5058 /* 4. Create realignment token using a target builtin, if available.
5059 It is done either inside the containing loop, or before LOOP (as
5060 determined above). */
5063 {
5064 tree builtin_decl;
5066 /* Compute INIT_ADDR - the initial addressed accessed by this memref. */
5069 else
5070 {
5071 /* Generate the INIT_ADDR computation outside LOOP. */
5077 }
5089 else
5090 {
5091 /* Generate the misalignment computation outside LOOP. */
5095 }
5099 /* The result of the CALL_EXPR to this builtin is determined from
5100 the value of the parameter and no global variables are touched
5101 which makes the builtin a "const" function. Requiring the
5102 builtin to have the "const" attribute makes it unnecessary
5103 to call mark_call_clobbered. */
5105 }
5114 /* 5. Create msq = phi <msq_init, lsq> in loop */
5124 }
5127 /* Function vect_strided_load_supported.
5129 Returns TRUE is EXTRACT_EVEN and EXTRACT_ODD operations are supported,
5130 and FALSE otherwise. */
5132 static bool
5134 {
5142 {
5146 }
5149 {
5153 }
5157 {
5161 }
5164 {
5168 }
5170 }
5173 /* Function vect_permute_load_chain.
5175 Given a chain of interleaved loads in DR_CHAIN of LENGTH that must be
5176 a power of 2, generate extract_even/odd stmts to reorder the input data
5177 correctly. Return the final references for loads in RESULT_CHAIN.
5179 E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8.
5180 The input is 4 vectors each containing 8 elements. We assign a number to each
5181 element, the input sequence is:
5183 1st vec: 0 1 2 3 4 5 6 7
5184 2nd vec: 8 9 10 11 12 13 14 15
5185 3rd vec: 16 17 18 19 20 21 22 23
5186 4th vec: 24 25 26 27 28 29 30 31
5188 The output sequence should be:
5190 1st vec: 0 4 8 12 16 20 24 28
5191 2nd vec: 1 5 9 13 17 21 25 29
5192 3rd vec: 2 6 10 14 18 22 26 30
5193 4th vec: 3 7 11 15 19 23 27 31
5195 i.e., the first output vector should contain the first elements of each
5196 interleaving group, etc.
5198 We use extract_even/odd instructions to create such output. The input of each
5199 extract_even/odd operation is two vectors
5200 1st vec 2nd vec
5201 0 1 2 3 4 5 6 7
5203 and the output is the vector of extracted even/odd elements. The output of
5204 extract_even will be: 0 2 4 6
5205 and of extract_odd: 1 3 5 7
5208 The permutation is done in log LENGTH stages. In each stage extract_even and
5209 extract_odd stmts are created for each pair of vectors in DR_CHAIN in their
5210 order. In our example,
5212 E1: extract_even (1st vec, 2nd vec)
5213 E2: extract_odd (1st vec, 2nd vec)
5214 E3: extract_even (3rd vec, 4th vec)
5215 E4: extract_odd (3rd vec, 4th vec)
5217 The output for the first stage will be:
5219 E1: 0 2 4 6 8 10 12 14
5220 E2: 1 3 5 7 9 11 13 15
5221 E3: 16 18 20 22 24 26 28 30
5222 E4: 17 19 21 23 25 27 29 31
5224 In order to proceed and create the correct sequence for the next stage (or
5225 for the correct output, if the second stage is the last one, as in our
5226 example), we first put the output of extract_even operation and then the
5227 output of extract_odd in RESULT_CHAIN (which is then copied to DR_CHAIN).
5228 The input for the second stage is:
5230 1st vec (E1): 0 2 4 6 8 10 12 14
5231 2nd vec (E3): 16 18 20 22 24 26 28 30
5232 3rd vec (E2): 1 3 5 7 9 11 13 15
5233 4th vec (E4): 17 19 21 23 25 27 29 31
5235 The output of the second stage:
5237 E1: 0 4 8 12 16 20 24 28
5238 E2: 2 6 10 14 18 22 26 30
5239 E3: 1 5 9 13 17 21 25 29
5240 E4: 3 7 11 15 19 23 27 31
5242 And RESULT_CHAIN after reordering:
5244 1st vec (E1): 0 4 8 12 16 20 24 28
5245 2nd vec (E3): 1 5 9 13 17 21 25 29
5246 3rd vec (E2): 2 6 10 14 18 22 26 30
5247 4th vec (E4): 3 7 11 15 19 23 27 31. */
5249 static bool
5252 tree stmt,
5255 {
5258 tree tmp;
5262 /* Check that the operation is supported. */
5268 {
5270 {
5274 /* data_ref = permute_even (first_data_ref, second_data_ref); */
5290 /* data_ref = permute_odd (first_data_ref, second_data_ref); */
5304 }
5306 }
5308 }
5311 /* Function vect_transform_strided_load.
5313 Given a chain of input interleaved data-refs (in DR_CHAIN), build statements
5314 to perform their permutation and ascribe the result vectorized statements to
5315 the scalar statements.
5316 */
5318 static bool
5321 {
5327 tree tmp_data_ref;
5329 /* DR_CHAIN contains input data-refs that are a part of the interleaving.
5330 RESULT_CHAIN is the output of vect_permute_load_chain, it contains permuted
5331 vectors, that are ready for vector computation. */
5333 /* Permute. */
5337 /* Put a permuted data-ref in the VECTORIZED_STMT field.
5338 Since we scan the chain starting from it's first node, their order
5339 corresponds the order of data-refs in RESULT_CHAIN. */
5343 {
5347 /* Skip the gaps. Loads created for the gaps will be removed by dead
5348 code elimination pass later.
5349 DR_GROUP_GAP is the number of steps in elements from the previous
5350 access (if there is no gap DR_GROUP_GAP is 1). We skip loads that
5351 correspond to the gaps.
5352 */
5354 {
5355 gap_count++;
5357 }
5360 {
5362 /* We assume that if VEC_STMT is not NULL, this is a case of multiple
5363 copies, and we put the new vector statement in the first available
5364 RELATED_STMT. */
5367 else
5368 {
5373 {
5376 }
5378 }
5381 /* If NEXT_STMT accesses the same DR as the previous statement,
5382 put the same TMP_DATA_REF as its vectorized statement; otherwise
5383 get the next data-ref from RESULT_CHAIN. */
5386 }
5387 }
5389 }
5392 /* vectorizable_load.
5394 Check if STMT reads a non scalar data-ref (array/pointer/structure) that
5395 can be vectorized.
5396 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
5397 stmt to replace it, put it in VEC_STMT, and insert it at BSI.
5398 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
5400 bool
5402 slp_tree slp_node)
5403 {
5404 tree scalar_dest;
5407 tree op;
5409 stmt_vec_info prev_stmt_info;
5416 tree new_temp;
5419 tree dummy;
5422 tree ptr_incr;
5432 tree first_stmt;
5433 tree scalar_type;
5440 /* FORNOW: SLP with multiple types is not supported. The SLP analysis verifies
5441 this, so we can safely override NCOPIES with 1 here. */
5447 /* FORNOW. This restriction should be relaxed. */
5449 {
5453 }
5461 /* FORNOW: not yet supported. */
5463 {
5467 }
5469 /* Is vectorizable load? */
5489 /* FORNOW. In some cases can vectorize even if data-type not supported
5490 (e.g. - data copies). */
5492 {
5496 }
5498 /* Check if the load is a part of an interleaving chain. */
5500 {
5502 /* FORNOW */
5505 /* Check if interleaving is supported. */
5509 }
5512 {
5516 }
5521 /** Transform. **/
5524 {
5526 /* Check if the chain of loads is already vectorized. */
5528 {
5531 }
5536 /* VEC_NUM is the number of vect stmts to be created for this group. */
5538 {
5541 }
5542 else
5544 }
5545 else
5546 {
5550 }
5555 /* In case the vectorization factor (VF) is bigger than the number
5556 of elements that we can fit in a vectype (nunits), we have to generate
5557 more than one vector stmt - i.e - we need to "unroll" the
5558 vector stmt by a factor VF/nunits. In doing so, we record a pointer
5559 from one copy of the vector stmt to the next, in the field
5560 STMT_VINFO_RELATED_STMT. This is necessary in order to allow following
5561 stages to find the correct vector defs to be used when vectorizing
5562 stmts that use the defs of the current stmt. The example below illustrates
5563 the vectorization process when VF=16 and nunits=4 (i.e - we need to create
5564 4 vectorized stmts):
5566 before vectorization:
5567 RELATED_STMT VEC_STMT
5568 S1: x = memref - -
5569 S2: z = x + 1 - -
5571 step 1: vectorize stmt S1:
5572 We first create the vector stmt VS1_0, and, as usual, record a
5573 pointer to it in the STMT_VINFO_VEC_STMT of the scalar stmt S1.
5574 Next, we create the vector stmt VS1_1, and record a pointer to
5575 it in the STMT_VINFO_RELATED_STMT of the vector stmt VS1_0.
5576 Similarly, for VS1_2 and VS1_3. This is the resulting chain of
5577 stmts and pointers:
5578 RELATED_STMT VEC_STMT
5579 VS1_0: vx0 = memref0 VS1_1 -
5580 VS1_1: vx1 = memref1 VS1_2 -
5581 VS1_2: vx2 = memref2 VS1_3 -
5582 VS1_3: vx3 = memref3 - -
5583 S1: x = load - VS1_0
5584 S2: z = x + 1 - -
5586 See in documentation in vect_get_vec_def_for_stmt_copy for how the
5587 information we recorded in RELATED_STMT field is used to vectorize
5588 stmt S2. */
5590 /* In case of interleaving (non-unit strided access):
5592 S1: x2 = &base + 2
5593 S2: x0 = &base
5594 S3: x1 = &base + 1
5595 S4: x3 = &base + 3
5597 Vectorized loads are created in the order of memory accesses
5598 starting from the access of the first stmt of the chain:
5600 VS1: vx0 = &base
5601 VS2: vx1 = &base + vec_size*1
5602 VS3: vx3 = &base + vec_size*2
5603 VS4: vx4 = &base + vec_size*3
5605 Then permutation statements are generated:
5607 VS5: vx5 = VEC_EXTRACT_EVEN_EXPR < vx0, vx1 >
5608 VS6: vx6 = VEC_EXTRACT_ODD_EXPR < vx0, vx1 >
5609 ...
5611 And they are put in STMT_VINFO_VEC_STMT of the corresponding scalar stmts
5612 (the order of the data-refs in the output of vect_permute_load_chain
5613 corresponds to the order of scalar stmts in the interleaving chain - see
5614 the documentation of vect_permute_load_chain()).
5615 The generation of permutation stmts and recording them in
5616 STMT_VINFO_VEC_STMT is done in vect_transform_strided_load().
5618 In case of both multiple types and interleaving, the vector loads and
5619 permutation stmts above are created for every copy. The result vector stmts
5620 are put in STMT_VINFO_VEC_STMT for the first copy and in the corresponding
5621 STMT_VINFO_RELATED_STMT for the next copies. */
5623 /* If the data reference is aligned (dr_aligned) or potentially unaligned
5624 on a target that supports unaligned accesses (dr_unaligned_supported)
5625 we generate the following code:
5626 p = initial_addr;
5627 indx = 0;
5628 loop {
5629 p = p + indx * vectype_size;
5630 vec_dest = *(p);
5631 indx = indx + 1;
5632 }
5634 Otherwise, the data reference is potentially unaligned on a target that
5635 does not support unaligned accesses (dr_explicit_realign_optimized) -
5636 then generate the following code, in which the data in each iteration is
5637 obtained by two vector loads, one from the previous iteration, and one
5638 from the current iteration:
5639 p1 = initial_addr;
5640 msq_init = *(floor(p1))
5641 p2 = initial_addr + VS - 1;
5642 realignment_token = call target_builtin;
5643 indx = 0;
5644 loop {
5645 p2 = p2 + indx * vectype_size
5646 lsq = *(floor(p2))
5647 vec_dest = realign_load (msq, lsq, realignment_token)
5648 indx = indx + 1;
5649 msq = lsq;
5650 } */
5652 /* If the misalignment remains the same throughout the execution of the
5653 loop, we can create the init_addr and permutation mask at the loop
5654 preheader. Otherwise, it needs to be created inside the loop.
5655 This can only occur when vectorizing memory accesses in the inner-loop
5656 nested within an outer-loop that is being vectorized. */
5660 {
5663 }
5668 {
5673 {
5676 }
5677 }
5678 else
5683 {
5684 /* 1. Create the vector pointer update chain. */
5690 else
5691 dataref_ptr =
5695 {
5698 NULL_TREE);
5700 /* 2. Create the vector-load in the loop. */
5702 {
5708 {
5713 data_ref =
5716 }
5718 {
5725 dr_explicit_realign,
5743 }
5749 }
5757 /* 3. Handle explicit realignment if necessary/supported. Create in
5758 loop: vec_dest = realign_load (msq, lsq, realignment_token) */
5761 {
5767 realignment_token);
5774 {
5778 }
5779 }
5781 /* 4. Handle invariant-load. */
5783 {
5787 {
5792 /* CHECKME: bitpos depends on endianess? */
5798 vec_dest =
5807 /* FIXME: use build_constructor directly. */
5811 }
5812 else
5814 }
5816 /* Collect vector loads and later create their permutation in
5817 vect_transform_strided_load (). */
5821 /* Store vector loads in the corresponding SLP_NODE. */
5824 }
5826 /* FORNOW: SLP with multiple types is unsupported. */
5831 {
5836 }
5837 else
5838 {
5841 else
5844 }
5845 }
5848 }
5851 /* Function vectorizable_live_operation.
5853 STMT computes a value that is used outside the loop. Check if
5854 it can be supported. */
5856 bool
5860 {
5861 tree operation;
5867 tree op;
5882 /* FORNOW. CHECKME. */
5889 /* FORNOW: support only if all uses are invariant. This means
5890 that the scalar operations can remain in place, unvectorized.
5891 The original last scalar value that they compute will be used. */
5894 {
5897 {
5901 }
5905 }
5907 /* No transformation is required for the cases we currently support. */
5909 }
5912 /* Function vect_is_simple_cond.
5914 Input:
5915 LOOP - the loop that is being vectorized.
5916 COND - Condition that is checked for simple use.
5918 Returns whether a COND can be vectorized. Checks whether
5919 condition operands are supportable using vec_is_simple_use. */
5921 static bool
5923 {
5925 tree def;
5935 {
5939 }
5945 {
5949 }
5955 }
5957 /* vectorizable_condition.
5959 Check if STMT is conditional modify expression that can be vectorized.
5960 If VEC_STMT is also passed, vectorize the STMT: create a vectorized
5961 stmt using VEC_COND_EXPR to replace it, put it in VEC_STMT, and insert it
5962 at BSI.
5964 Return FALSE if not a vectorizable STMT, TRUE otherwise. */
5966 bool
5968 {
5977 tree new_temp;
5980 tree def;
5995 /* FORNOW: SLP not supported. */
5999 /* FORNOW: not yet supported. */
6001 {
6005 }
6007 /* Is vectorizable conditional operation? */
6023 /* We do not handle two different vector types for the condition
6024 and the values. */
6029 {
6034 }
6041 {
6046 }
6056 {
6059 }
6061 /* Transform */
6063 /* Handle def. */
6067 /* Handle cond expr. */
6068 vec_cond_lhs =
6070 vec_cond_rhs =
6075 /* Arguments are ready. create the new vector stmt. */
6087 }
6090 /* Function vect_transform_stmt.
6092 Create a vectorized stmt to replace STMT, and insert it at BSI. */
6094 static bool
6096 slp_tree slp_node)
6097 {
6101 tree orig_stmt_in_pattern;
6105 {
6148 {
6149 /* In case of interleaving, the whole chain is vectorized when the
6150 last store in the chain is reached. Store stmts before the last
6151 one are skipped, and there vec_stmt_info shouldn't be freed
6152 meanwhile. */
6156 }
6157 else
6180 {
6184 }
6185 }
6189 {
6192 }
6195 {
6199 {
6201 /* STMT was inserted by the vectorizer to replace a computation idiom.
6202 ORIG_STMT_IN_PATTERN is a stmt in the original sequence that
6203 computed this idiom. We need to record a pointer to VEC_STMT in
6204 the stmt_info of ORIG_STMT_IN_PATTERN. See more details in the
6205 documentation of vect_pattern_recog. */
6207 {
6210 }
6211 }
6212 }
6215 }
6218 /* This function builds ni_name = number of iterations loop executes
6219 on the loop preheader. */
6221 static tree
6223 {
6225 edge pe;
6235 {
6238 }
6241 }
6244 /* This function generates the following statements:
6246 ni_name = number of iterations loop executes
6247 ratio = ni_name / vf
6248 ratio_mult_vf_name = ratio * vf
6250 and places them at the loop preheader edge. */
6252 static void
6257 {
6259 edge pe;
6260 basic_block new_bb;
6262 tree var;
6263 tree ratio_name;
6264 tree ratio_mult_vf_name;
6268 tree log_vf;
6272 /* Generate temporary variable that contains
6273 number of iterations loop executes. */
6278 /* Create: ratio = ni >> log2(vf) */
6282 {
6290 }
6292 /* Create: ratio_mult_vf = ratio << log2 (vf). */
6297 {
6306 }
6313 }
6316 /* Function vect_update_ivs_after_vectorizer.
6318 "Advance" the induction variables of LOOP to the value they should take
6319 after the execution of LOOP. This is currently necessary because the
6320 vectorizer does not handle induction variables that are used after the
6321 loop. Such a situation occurs when the last iterations of LOOP are
6322 peeled, because:
6323 1. We introduced new uses after LOOP for IVs that were not originally used
6324 after LOOP: the IVs of LOOP are now used by an epilog loop.
6325 2. LOOP is going to be vectorized; this means that it will iterate N/VF
6326 times, whereas the loop IVs should be bumped N times.
6328 Input:
6329 - LOOP - a loop that is going to be vectorized. The last few iterations
6330 of LOOP were peeled.
6331 - NITERS - the number of iterations that LOOP executes (before it is
6332 vectorized). i.e, the number of times the ivs should be bumped.
6333 - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path
6334 coming out from LOOP on which there are uses of the LOOP ivs
6335 (this is the path from LOOP->exit to epilog_loop->preheader).
6337 The new definitions of the ivs are placed in LOOP->exit.
6338 The phi args associated with the edge UPDATE_E in the bb
6339 UPDATE_E->dest are updated accordingly.
6341 Assumption 1: Like the rest of the vectorizer, this function assumes
6342 a single loop exit that has a single predecessor.
6344 Assumption 2: The phi nodes in the LOOP header and in update_bb are
6345 organized in the same order.
6347 Assumption 3: The access function of the ivs is simple enough (see
6348 vect_can_advance_ivs_p). This assumption will be relaxed in the future.
6350 Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path
6351 coming out of LOOP on which the ivs of LOOP are used (this is the path
6352 that leads to the epilog loop; other paths skip the epilog loop). This
6353 path starts with the edge UPDATE_E, and its destination (denoted update_bb)
6354 needs to have its phis updated.
6355 */
6357 static void
6359 edge update_e)
6360 {
6366 /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */
6368 /* Make sure there exists a single-predecessor exit bb: */
6374 {
6376 tree evolution_part;
6377 tree init_expr;
6378 tree step_expr;
6380 block_stmt_iterator last_bsi;
6383 {
6386 }
6388 /* Skip virtual phi's. */
6390 {
6394 }
6396 /* Skip reduction phis. */
6398 {
6402 }
6406 evolution_part =
6410 /* FORNOW: We do not support IVs whose evolution function is a polynomial
6411 of degree >= 2 or exponential. */
6420 init_expr,
6424 else
6428 niters),
6429 step_expr),
6430 init_expr);
6441 /* Fix phi expressions in the successor bb. */
6443 }
6444 }
6447 /* Function vect_do_peeling_for_loop_bound
6449 Peel the last iterations of the loop represented by LOOP_VINFO.
6450 The peeled iterations form a new epilog loop. Given that the loop now
6451 iterates NITERS times, the new epilog loop iterates
6452 NITERS % VECTORIZATION_FACTOR times.
6454 The original loop will later be made to iterate
6455 NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO). */
6457 static void
6459 {
6463 edge update_e;
6464 basic_block preheader;
6475 /* Generate the following variables on the preheader of original loop:
6477 ni_name = number of iteration the original loop executes
6478 ratio = ni_name / vf
6479 ratio_mult_vf_name = ratio * vf */
6485 /* Analyze cost to set threshhold for vectorized loop. */
6490 /* Use the cost model only if it is more conservative than user specified
6491 threshold. */
6495 && (!min_scalar_loop_bound
6506 th);
6509 #ifdef ENABLE_CHECKING
6511 #endif
6513 /* A guard that controls whether the new_loop is to be executed or skipped
6514 is placed in LOOP->exit. LOOP->exit therefore has two successors - one
6515 is the preheader of NEW_LOOP, where the IVs from LOOP are used. The other
6516 is a bb after NEW_LOOP, where these IVs are not used. Find the edge that
6517 is on the path where the LOOP IVs are used and need to be updated. */
6522 else
6525 /* Update IVs of original loop as if they were advanced
6526 by ratio_mult_vf_name steps. */
6529 /* After peeling we have to reset scalar evolution analyzer. */
6533 }
6536 /* Function vect_gen_niters_for_prolog_loop
6538 Set the number of iterations for the loop represented by LOOP_VINFO
6539 to the minimum between LOOP_NITERS (the original iteration count of the loop)
6540 and the misalignment of DR - the data reference recorded in
6541 LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO). As a result, after the execution of
6542 this loop, the data reference DR will refer to an aligned location.
6544 The following computation is generated:
6546 If the misalignment of DR is known at compile time:
6547 addr_mis = int mis = DR_MISALIGNMENT (dr);
6548 Else, compute address misalignment in bytes:
6549 addr_mis = addr & (vectype_size - 1)
6551 prolog_niters = min ( LOOP_NITERS , (VF - addr_mis/elem_size)&(VF-1) )
6553 (elem_size = element type size; an element is the scalar element
6554 whose type is the inner type of the vectype)
6556 For interleaving,
6558 prolog_niters = min ( LOOP_NITERS ,
6559 (VF/group_size - addr_mis/elem_size)&(VF/group_size-1) )
6560 where group_size is the size of the interleaved group.
6562 The above formulas assume that VF == number of elements in the vector. This
6563 may not hold when there are multiple-types in the loop.
6564 In this case, for some data-references in the loop the VF does not represent
6565 the number of elements that fit in the vector. Therefore, instead of VF we
6566 use TYPE_VECTOR_SUBPARTS. */
6568 static tree
6570 {
6575 edge pe;
6576 basic_block new_bb;
6587 {
6588 /* For interleaved access element size must be multiplied by the size of
6589 the interleaved group. */
6593 }
6598 {
6606 }
6607 else
6608 {
6616 tree elem_size_log =
6620 tree byte_misalign;
6621 tree elem_misalign;
6626 /* Create: byte_misalign = addr & (vectype_size - 1) */
6627 byte_misalign =
6630 /* Create: elem_misalign = byte_misalign / element_size */
6631 elem_misalign =
6634 /* Create: (niters_type) (nelements - elem_misalign)&(nelements - 1) */
6638 }
6640 /* Create: prolog_loop_niters = min (iters, loop_niters) */
6641 /* If the loop bound is known at compile time we already verified that it is
6642 greater than vf; since the misalignment ('iters') is at most vf, there's
6643 no need to generate the MIN_EXPR in this case. */
6648 {
6651 }
6657 /* Insert stmt on loop preheader edge. */
6659 {
6662 }
6665 }
6668 /* Function vect_update_init_of_dr
6670 NITERS iterations were peeled from LOOP. DR represents a data reference
6671 in LOOP. This function updates the information recorded in DR to
6672 account for the fact that the first NITERS iterations had already been
6673 executed. Specifically, it updates the OFFSET field of DR. */
6675 static void
6677 {
6683 }
6686 /* Function vect_update_inits_of_drs
6688 NITERS iterations were peeled from the loop represented by LOOP_VINFO.
6689 This function updates the information recorded for the data references in
6690 the loop to account for the fact that the first NITERS iterations had
6691 already been executed. Specifically, it updates the initial_condition of
6692 the access_function of all the data_references in the loop. */
6694 static void
6696 {
6706 }
6709 /* Function vect_do_peeling_for_alignment
6711 Peel the first 'niters' iterations of the loop represented by LOOP_VINFO.
6712 'niters' is set to the misalignment of one of the data references in the
6713 loop, thereby forcing it to refer to an aligned location at the beginning
6714 of the execution of this loop. The data reference for which we are
6715 peeling is recorded in LOOP_VINFO_UNALIGNED_DR. */
6717 static void
6719 {
6722 tree n_iters;
6733 /* Peel the prolog loop and iterate it niters_of_prolog_loop. */
6734 new_loop =
6738 #ifdef ENABLE_CHECKING
6740 #endif
6742 /* Update number of times loop executes. */
6747 /* Update the init conditions of the access functions of all data refs. */
6750 /* After peeling we have to reset scalar evolution analyzer. */
6754 }
6757 /* Function vect_create_cond_for_align_checks.
6759 Create a conditional expression that represents the alignment checks for
6760 all of data references (array element references) whose alignment must be
6761 checked at runtime.
6763 Input:
6764 LOOP_VINFO - two fields of the loop information are used.
6765 LOOP_VINFO_PTR_MASK is the mask used to check the alignment.
6766 LOOP_VINFO_MAY_MISALIGN_STMTS contains the refs to be checked.
6768 Output:
6769 COND_EXPR_STMT_LIST - statements needed to construct the conditional
6770 expression.
6771 The returned value is the conditional expression to be used in the if
6772 statement that controls which version of the loop gets executed at runtime.
6774 The algorithm makes two assumptions:
6775 1) The number of bytes "n" in a vector is a power of 2.
6776 2) An address "a" is aligned if a%n is zero and that this
6777 test can be done as a&(n-1) == 0. For example, for 16
6778 byte vectors the test is a&0xf == 0. */
6780 static tree
6783 {
6789 tree mask_cst;
6791 tree psize;
6792 tree int_ptrsize_type;
6796 tree ptrsize_zero;
6798 /* Check that mask is one less than a power of 2, i.e., mask is
6799 all zeros followed by all ones. */
6802 /* CHECKME: what is the best integer or unsigned type to use to hold a
6803 cast from a pointer value? */
6805 int_ptrsize_type
6808 /* Create expression (mask & (dr_1 || ... || dr_n)) where dr_i is the address
6809 of the first vector of the i'th data reference. */
6812 {
6814 tree addr_base;
6818 /* create: addr_tmp = (int)(address_of_first_vector) */
6834 /* The addresses are OR together. */
6837 {
6838 /* create: or_tmp = or_tmp | addr_tmp */
6849 }
6850 else
6857 /* create: and_tmp = or_tmp & mask */
6867 /* Make and_tmp the left operand of the conditional test against zero.
6868 if and_tmp has a nonzero bit then some address is unaligned. */
6872 }
6874 /* Function vect_vfa_segment_size.
6876 Create an expression that computes the size of segment
6877 that will be accessed for a data reference. The functions takes into
6878 account that realignment loads may access one more vector.
6880 Input:
6881 DR: The data reference.
6882 VECT_FACTOR: vectorization factor.
6884 Return an expression whose value is the size of segment which will be
6885 accessed by DR. */
6887 static tree
6889 {
6894 {
6895 tree vector_size = TYPE_SIZE_UNIT
6900 }
6902 }
6904 /* Function vect_create_cond_for_alias_checks.
6906 Create a conditional expression that represents the run-time checks for
6907 overlapping of address ranges represented by a list of data references
6908 relations passed as input.
6910 Input:
6911 COND_EXPR - input conditional expression. New conditions will be chained
6912 with logical and operation.
6913 LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs
6914 to be checked.
6916 Output:
6917 COND_EXPR - conditional expression.
6918 COND_EXPR_STMT_LIST - statements needed to construct the conditional
6919 expression.
6922 The returned value is the conditional expression to be used in the if
6923 statement that controls which version of the loop gets executed at runtime.
6924 */
6926 static void
6930 {
6934 tree vect_factor =
6937 ddr_p ddr;
6939 tree part_cond_expr;
6941 /* Create expression
6942 ((store_ptr_0 + store_segment_length_0) < load_ptr_0)
6943 || (load_ptr_0 + load_segment_length_0) < store_ptr_0))
6944 &&
6945 ...
6946 &&
6947 ((store_ptr_n + store_segment_length_n) < load_ptr_n)
6948 || (load_ptr_n + load_segment_length_n) < store_ptr_n)) */
6954 {
6965 {
6968 }
6974 {
6977 }
6979 addr_base_a =
6982 addr_base_b =
6990 {
6996 }
6999 part_cond_expr =
7003 addr_base_a,
7004 segment_length_a),
7005 addr_base_b),
7008 addr_base_b,
7009 segment_length_b),
7010 addr_base_a));
7015 else
7017 }
7022 }
7024 /* Function vect_loop_versioning.
7026 If the loop has data references that may or may not be aligned or/and
7027 has data reference relations whose independence was not proven then
7028 two versions of the loop need to be generated, one which is vectorized
7029 and one which isn't. A test is then generated to control which of the
7030 loops is executed. The test checks for the alignment of all of the
7031 data references that may or may not be aligned. An additional
7032 sequence of runtime tests is generated for each pairs of DDRs whose
7033 independence was not proven. The vectorized version of loop is
7034 executed only if both alias and alignment tests are passed. */
7036 static void
7038 {
7043 basic_block condition_bb;
7044 block_stmt_iterator cond_exp_bsi;
7045 basic_block merge_bb;
7046 basic_block new_exit_bb;
7050 tree gimplify_stmt_list;
7057 cond_expr =
7063 cond_expr =
7065 cond_expr =
7067 NULL_TREE);
7075 /* Loop versioning violates an assumption we try to maintain during
7076 vectorization - that the loop exit block has a single predecessor.
7077 After versioning, the exit block of both loop versions is the same
7078 basic block (i.e. it has two predecessors). Just in order to simplify
7079 following transformations in the vectorizer, we fix this situation
7080 here by adding a new (empty) block on the exit-edge of the loop,
7081 with the proper loop-exit phis to maintain loop-closed-form. */
7091 {
7093 new_exit_bb);
7097 }
7099 /* End loop-exit-fixes after versioning. */
7103 {
7106 }
7107 }
7109 /* Remove a group of stores (for SLP or interleaving), free their
7110 stmt_vec_info. */
7112 static void
7114 {
7115 stmt_ann_t ann;
7117 tree tmp;
7118 stmt_vec_info next_stmt_info;
7119 block_stmt_iterator next_si;
7122 {
7123 /* Free the attached stmt_vec_info and remove the stmt. */
7132 }
7133 }
7136 /* Vectorize SLP instance tree in postorder. */
7138 static bool
7140 {
7141 tree stmt;
7143 block_stmt_iterator si;
7144 stmt_vec_info stmt_info;
7158 {
7161 }
7166 {
7168 /* If IS_STORE is TRUE, the vectorization of the
7169 interleaving chain was completed - free all the stores in
7170 the chain. */
7172 else
7173 /* FORNOW: SLP originates only from strided stores. */
7177 }
7179 /* FORNOW: SLP originates only from strided stores. */
7181 }
7184 static bool
7186 {
7189 slp_instance instance;
7196 {
7198 /* For each SLP instance calculate number of vector stmts to be created
7199 for the scalar stmts in each node of the SLP tree. Number of vector
7200 elements in one vector iteration is the number of scalar elements in
7201 one scalar iteration (GROUP_SIZE) multiplied by VF divided by vector
7202 size. */
7205 /* Schedule the tree of INSTANCE. */
7207 vec_stmts_size);
7212 }
7215 }
7217 /* Function vect_transform_loop.
7219 The analysis phase has determined that the loop is vectorizable.
7220 Vectorize the loop - created vectorized stmts to replace the scalar
7221 stmts in the loop, and update the loop exit condition. */
7223 void
7225 {
7241 /* CHECKME: we wouldn't need this if we called update_ssa once
7242 for all loops. */
7245 /* Peel the loop if there are data refs with unknown alignment.
7246 Only one data ref with unknown store is allowed. */
7251 /* If the loop has a symbolic number of iterations 'n' (i.e. it's not a
7252 compile time constant), or it is a constant that doesn't divide by the
7253 vectorization factor, then an epilog loop needs to be created.
7254 We therefore duplicate the loop: the original loop will be vectorized,
7255 and will compute the first (n/VF) iterations. The second copy of the loop
7256 will remain scalar and will compute the remaining (n%VF) iterations.
7257 (VF is the vectorization factor). */
7263 else
7267 /* 1) Make sure the loop header has exactly two entries
7268 2) Make sure we have a preheader basic block. */
7274 /* FORNOW: the vectorizer supports only loops which body consist
7275 of one basic block (header + empty latch). When the vectorizer will
7276 support more involved loop forms, the order by which the BBs are
7277 traversed need to be reconsidered. */
7280 {
7282 stmt_vec_info stmt_info;
7283 tree phi;
7286 {
7288 {
7291 }
7306 {
7310 }
7311 }
7314 {
7319 {
7322 }
7326 /* vector stmts created in the outer-loop during vectorization of
7327 stmts in an inner-loop may not have a stmt_info, and do not
7328 need to be vectorized. */
7330 {
7333 }
7337 {
7340 }
7343 nunits =
7348 /* For SLP VF is set according to unrolling factor, and not to
7349 vector size, hence for SLP this print is not valid. */
7352 /* SLP. Schedule all the SLP instances when the first SLP stmt is
7353 reached. */
7355 {
7357 {
7365 /* IS_STORE is true if STMT is a store. Stores cannot be of
7366 hybrid SLP type. They are removed in
7367 vect_schedule_slp_instance and their vinfo is destroyed. */
7369 {
7372 }
7373 }
7375 /* Hybrid SLP stmts must be vectorized in addition to SLP. */
7377 {
7380 }
7381 }
7383 /* -------- vectorize statement ------------ */
7390 {
7391 stmt_ann_t ann;
7393 {
7394 /* Interleaving. If IS_STORE is TRUE, the vectorization of the
7395 interleaving chain was completed - free all the stores in
7396 the chain. */
7398 tree tmp;
7399 stmt_vec_info next_stmt_info;
7402 {
7405 /* Free the attached stmt_vec_info and remove the stmt. */
7412 }
7415 }
7416 else
7417 {
7418 /* Free the attached stmt_vec_info and remove the stmt. */
7424 }
7425 }
7434 /* The memory tags and pointers in vectorized statements need to
7435 have their SSA forms updated. FIXME, why can't this be delayed
7436 until all the loops have been transformed? */
7443 }