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Diffstat (limited to 'gcc-4.8.3/gcc/tree-vect-data-refs.c')
| -rw-r--r-- | gcc-4.8.3/gcc/tree-vect-data-refs.c | 5009 |
1 files changed, 5009 insertions, 0 deletions
diff --git a/gcc-4.8.3/gcc/tree-vect-data-refs.c b/gcc-4.8.3/gcc/tree-vect-data-refs.c new file mode 100644 index 000000000..d8d1435c3 --- /dev/null +++ b/gcc-4.8.3/gcc/tree-vect-data-refs.c @@ -0,0 +1,5009 @@ +/* Data References Analysis and Manipulation Utilities for Vectorization. + Copyright (C) 2003-2013 Free Software Foundation, Inc. + Contributed by Dorit Naishlos <dorit@il.ibm.com> + and Ira Rosen <irar@il.ibm.com> + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 3, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +<http://www.gnu.org/licenses/>. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "dumpfile.h" +#include "tm.h" +#include "ggc.h" +#include "tree.h" +#include "tm_p.h" +#include "target.h" +#include "basic-block.h" +#include "gimple-pretty-print.h" +#include "tree-flow.h" +#include "dumpfile.h" +#include "cfgloop.h" +#include "tree-chrec.h" +#include "tree-scalar-evolution.h" +#include "tree-vectorizer.h" +#include "diagnostic-core.h" + +/* Need to include rtl.h, expr.h, etc. for optabs. */ +#include "expr.h" +#include "optabs.h" + +/* Return true if load- or store-lanes optab OPTAB is implemented for + COUNT vectors of type VECTYPE. NAME is the name of OPTAB. */ + +static bool +vect_lanes_optab_supported_p (const char *name, convert_optab optab, + tree vectype, unsigned HOST_WIDE_INT count) +{ + enum machine_mode mode, array_mode; + bool limit_p; + + mode = TYPE_MODE (vectype); + limit_p = !targetm.array_mode_supported_p (mode, count); + array_mode = mode_for_size (count * GET_MODE_BITSIZE (mode), + MODE_INT, limit_p); + + if (array_mode == BLKmode) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "no array mode for %s[" HOST_WIDE_INT_PRINT_DEC "]", + GET_MODE_NAME (mode), count); + return false; + } + + if (convert_optab_handler (optab, array_mode, mode) == CODE_FOR_nothing) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "cannot use %s<%s><%s>", name, + GET_MODE_NAME (array_mode), GET_MODE_NAME (mode)); + return false; + } + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "can use %s<%s><%s>", name, GET_MODE_NAME (array_mode), + GET_MODE_NAME (mode)); + + return true; +} + + +/* Return the smallest scalar part of STMT. + This is used to determine the vectype of the stmt. We generally set the + vectype according to the type of the result (lhs). For stmts whose + result-type is different than the type of the arguments (e.g., demotion, + promotion), vectype will be reset appropriately (later). Note that we have + to visit the smallest datatype in this function, because that determines the + VF. If the smallest datatype in the loop is present only as the rhs of a + promotion operation - we'd miss it. + Such a case, where a variable of this datatype does not appear in the lhs + anywhere in the loop, can only occur if it's an invariant: e.g.: + 'int_x = (int) short_inv', which we'd expect to have been optimized away by + invariant motion. However, we cannot rely on invariant motion to always + take invariants out of the loop, and so in the case of promotion we also + have to check the rhs. + LHS_SIZE_UNIT and RHS_SIZE_UNIT contain the sizes of the corresponding + types. */ + +tree +vect_get_smallest_scalar_type (gimple stmt, HOST_WIDE_INT *lhs_size_unit, + HOST_WIDE_INT *rhs_size_unit) +{ + tree scalar_type = gimple_expr_type (stmt); + HOST_WIDE_INT lhs, rhs; + + lhs = rhs = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (scalar_type)); + + if (is_gimple_assign (stmt) + && (gimple_assign_cast_p (stmt) + || gimple_assign_rhs_code (stmt) == WIDEN_MULT_EXPR + || gimple_assign_rhs_code (stmt) == WIDEN_LSHIFT_EXPR + || gimple_assign_rhs_code (stmt) == FLOAT_EXPR)) + { + tree rhs_type = TREE_TYPE (gimple_assign_rhs1 (stmt)); + + rhs = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (rhs_type)); + if (rhs < lhs) + scalar_type = rhs_type; + } + + *lhs_size_unit = lhs; + *rhs_size_unit = rhs; + return scalar_type; +} + + +/* Find the place of the data-ref in STMT in the interleaving chain that starts + from FIRST_STMT. Return -1 if the data-ref is not a part of the chain. */ + +int +vect_get_place_in_interleaving_chain (gimple stmt, gimple first_stmt) +{ + gimple next_stmt = first_stmt; + int result = 0; + + if (first_stmt != GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt))) + return -1; + + while (next_stmt && next_stmt != stmt) + { + result++; + next_stmt = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next_stmt)); + } + + if (next_stmt) + return result; + else + return -1; +} + + +/* Function vect_insert_into_interleaving_chain. + + Insert DRA into the interleaving chain of DRB according to DRA's INIT. */ + +static void +vect_insert_into_interleaving_chain (struct data_reference *dra, + struct data_reference *drb) +{ + gimple prev, next; + tree next_init; + stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); + stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb)); + + prev = GROUP_FIRST_ELEMENT (stmtinfo_b); + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)); + while (next) + { + next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next))); + if (tree_int_cst_compare (next_init, DR_INIT (dra)) > 0) + { + /* Insert here. */ + GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)) = DR_STMT (dra); + GROUP_NEXT_ELEMENT (stmtinfo_a) = next; + return; + } + prev = next; + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)); + } + + /* We got to the end of the list. Insert here. */ + GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)) = DR_STMT (dra); + GROUP_NEXT_ELEMENT (stmtinfo_a) = NULL; +} + + +/* Function vect_update_interleaving_chain. + + For two data-refs DRA and DRB that are a part of a chain interleaved data + accesses, update the interleaving chain. DRB's INIT is smaller than DRA's. + + There are four possible cases: + 1. New stmts - both DRA and DRB are not a part of any chain: + FIRST_DR = DRB + NEXT_DR (DRB) = DRA + 2. DRB is a part of a chain and DRA is not: + no need to update FIRST_DR + no need to insert DRB + insert DRA according to init + 3. DRA is a part of a chain and DRB is not: + if (init of FIRST_DR > init of DRB) + FIRST_DR = DRB + NEXT(FIRST_DR) = previous FIRST_DR + else + insert DRB according to its init + 4. both DRA and DRB are in some interleaving chains: + choose the chain with the smallest init of FIRST_DR + insert the nodes of the second chain into the first one. */ + +static void +vect_update_interleaving_chain (struct data_reference *drb, + struct data_reference *dra) +{ + stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); + stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb)); + tree next_init, init_dra_chain, init_drb_chain; + gimple first_a, first_b; + tree node_init; + gimple node, prev, next, first_stmt; + + /* 1. New stmts - both DRA and DRB are not a part of any chain. */ + if (!GROUP_FIRST_ELEMENT (stmtinfo_a) && !GROUP_FIRST_ELEMENT (stmtinfo_b)) + { + GROUP_FIRST_ELEMENT (stmtinfo_a) = DR_STMT (drb); + GROUP_FIRST_ELEMENT (stmtinfo_b) = DR_STMT (drb); + GROUP_NEXT_ELEMENT (stmtinfo_b) = DR_STMT (dra); + return; + } + + /* 2. DRB is a part of a chain and DRA is not. */ + if (!GROUP_FIRST_ELEMENT (stmtinfo_a) && GROUP_FIRST_ELEMENT (stmtinfo_b)) + { + GROUP_FIRST_ELEMENT (stmtinfo_a) = GROUP_FIRST_ELEMENT (stmtinfo_b); + /* Insert DRA into the chain of DRB. */ + vect_insert_into_interleaving_chain (dra, drb); + return; + } + + /* 3. DRA is a part of a chain and DRB is not. */ + if (GROUP_FIRST_ELEMENT (stmtinfo_a) && !GROUP_FIRST_ELEMENT (stmtinfo_b)) + { + gimple old_first_stmt = GROUP_FIRST_ELEMENT (stmtinfo_a); + tree init_old = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt ( + old_first_stmt))); + gimple tmp; + + if (tree_int_cst_compare (init_old, DR_INIT (drb)) > 0) + { + /* DRB's init is smaller than the init of the stmt previously marked + as the first stmt of the interleaving chain of DRA. Therefore, we + update FIRST_STMT and put DRB in the head of the list. */ + GROUP_FIRST_ELEMENT (stmtinfo_b) = DR_STMT (drb); + GROUP_NEXT_ELEMENT (stmtinfo_b) = old_first_stmt; + + /* Update all the stmts in the list to point to the new FIRST_STMT. */ + tmp = old_first_stmt; + while (tmp) + { + GROUP_FIRST_ELEMENT (vinfo_for_stmt (tmp)) = DR_STMT (drb); + tmp = GROUP_NEXT_ELEMENT (vinfo_for_stmt (tmp)); + } + } + else + { + /* Insert DRB in the list of DRA. */ + vect_insert_into_interleaving_chain (drb, dra); + GROUP_FIRST_ELEMENT (stmtinfo_b) = GROUP_FIRST_ELEMENT (stmtinfo_a); + } + return; + } + + /* 4. both DRA and DRB are in some interleaving chains. */ + first_a = GROUP_FIRST_ELEMENT (stmtinfo_a); + first_b = GROUP_FIRST_ELEMENT (stmtinfo_b); + if (first_a == first_b) + return; + init_dra_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_a))); + init_drb_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_b))); + + if (tree_int_cst_compare (init_dra_chain, init_drb_chain) > 0) + { + /* Insert the nodes of DRA chain into the DRB chain. + After inserting a node, continue from this node of the DRB chain (don't + start from the beginning. */ + node = GROUP_FIRST_ELEMENT (stmtinfo_a); + prev = GROUP_FIRST_ELEMENT (stmtinfo_b); + first_stmt = first_b; + } + else + { + /* Insert the nodes of DRB chain into the DRA chain. + After inserting a node, continue from this node of the DRA chain (don't + start from the beginning. */ + node = GROUP_FIRST_ELEMENT (stmtinfo_b); + prev = GROUP_FIRST_ELEMENT (stmtinfo_a); + first_stmt = first_a; + } + + while (node) + { + node_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (node))); + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)); + while (next) + { + next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next))); + if (tree_int_cst_compare (next_init, node_init) > 0) + { + /* Insert here. */ + GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)) = node; + GROUP_NEXT_ELEMENT (vinfo_for_stmt (node)) = next; + prev = node; + break; + } + prev = next; + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)); + } + if (!next) + { + /* We got to the end of the list. Insert here. */ + GROUP_NEXT_ELEMENT (vinfo_for_stmt (prev)) = node; + GROUP_NEXT_ELEMENT (vinfo_for_stmt (node)) = NULL; + prev = node; + } + GROUP_FIRST_ELEMENT (vinfo_for_stmt (node)) = first_stmt; + node = GROUP_NEXT_ELEMENT (vinfo_for_stmt (node)); + } +} + +/* Check dependence between DRA and DRB for basic block vectorization. + If the accesses share same bases and offsets, we can compare their initial + constant offsets to decide whether they differ or not. In case of a read- + write dependence we check that the load is before the store to ensure that + vectorization will not change the order of the accesses. */ + +static bool +vect_drs_dependent_in_basic_block (struct data_reference *dra, + struct data_reference *drb) +{ + HOST_WIDE_INT type_size_a, type_size_b, init_a, init_b; + gimple earlier_stmt; + + /* We only call this function for pairs of loads and stores, but we verify + it here. */ + if (DR_IS_READ (dra) == DR_IS_READ (drb)) + { + if (DR_IS_READ (dra)) + return false; + else + return true; + } + + /* Check that the data-refs have same bases and offsets. If not, we can't + determine if they are dependent. */ + if (!operand_equal_p (DR_BASE_ADDRESS (dra), DR_BASE_ADDRESS (drb), 0) + || !dr_equal_offsets_p (dra, drb)) + return true; + + /* Check the types. */ + type_size_a = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dra)))); + type_size_b = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (drb)))); + + if (type_size_a != type_size_b + || !types_compatible_p (TREE_TYPE (DR_REF (dra)), + TREE_TYPE (DR_REF (drb)))) + return true; + + init_a = TREE_INT_CST_LOW (DR_INIT (dra)); + init_b = TREE_INT_CST_LOW (DR_INIT (drb)); + + /* Two different locations - no dependence. */ + if (init_a != init_b) + return false; + + /* We have a read-write dependence. Check that the load is before the store. + When we vectorize basic blocks, vector load can be only before + corresponding scalar load, and vector store can be only after its + corresponding scalar store. So the order of the acceses is preserved in + case the load is before the store. */ + earlier_stmt = get_earlier_stmt (DR_STMT (dra), DR_STMT (drb)); + if (DR_IS_READ (STMT_VINFO_DATA_REF (vinfo_for_stmt (earlier_stmt)))) + return false; + + return true; +} + + +/* Function vect_check_interleaving. + + Check if DRA and DRB are a part of interleaving. In case they are, insert + DRA and DRB in an interleaving chain. */ + +static bool +vect_check_interleaving (struct data_reference *dra, + struct data_reference *drb) +{ + HOST_WIDE_INT type_size_a, type_size_b, diff_mod_size, step, init_a, init_b; + + /* Check that the data-refs have same first location (except init) and they + are both either store or load (not load and store). */ + if (!operand_equal_p (DR_BASE_ADDRESS (dra), DR_BASE_ADDRESS (drb), 0) + || !dr_equal_offsets_p (dra, drb) + || !tree_int_cst_compare (DR_INIT (dra), DR_INIT (drb)) + || DR_IS_READ (dra) != DR_IS_READ (drb)) + return false; + + /* Check: + 1. data-refs are of the same type + 2. their steps are equal + 3. the step (if greater than zero) is greater than the difference between + data-refs' inits. */ + type_size_a = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dra)))); + type_size_b = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (drb)))); + + if (type_size_a != type_size_b + || tree_int_cst_compare (DR_STEP (dra), DR_STEP (drb)) + || !types_compatible_p (TREE_TYPE (DR_REF (dra)), + TREE_TYPE (DR_REF (drb)))) + return false; + + init_a = TREE_INT_CST_LOW (DR_INIT (dra)); + init_b = TREE_INT_CST_LOW (DR_INIT (drb)); + step = TREE_INT_CST_LOW (DR_STEP (dra)); + + if (init_a > init_b) + { + /* If init_a == init_b + the size of the type * k, we have an interleaving, + and DRB is accessed before DRA. */ + diff_mod_size = (init_a - init_b) % type_size_a; + + if (step && (init_a - init_b) > step) + return false; + + if (diff_mod_size == 0) + { + vect_update_interleaving_chain (drb, dra); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "Detected interleaving "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + return true; + } + } + else + { + /* If init_b == init_a + the size of the type * k, we have an + interleaving, and DRA is accessed before DRB. */ + diff_mod_size = (init_b - init_a) % type_size_a; + + if (step && (init_b - init_a) > step) + return false; + + if (diff_mod_size == 0) + { + vect_update_interleaving_chain (dra, drb); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "Detected interleaving "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + return true; + } + } + + return false; +} + +/* Check if data references pointed by DR_I and DR_J are same or + belong to same interleaving group. Return FALSE if drs are + different, otherwise return TRUE. */ + +static bool +vect_same_range_drs (data_reference_p dr_i, data_reference_p dr_j) +{ + gimple stmt_i = DR_STMT (dr_i); + gimple stmt_j = DR_STMT (dr_j); + + if (operand_equal_p (DR_REF (dr_i), DR_REF (dr_j), 0) + || (GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt_i)) + && GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt_j)) + && (GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt_i)) + == GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt_j))))) + return true; + else + return false; +} + +/* If address ranges represented by DDR_I and DDR_J are equal, + return TRUE, otherwise return FALSE. */ + +static bool +vect_vfa_range_equal (ddr_p ddr_i, ddr_p ddr_j) +{ + if ((vect_same_range_drs (DDR_A (ddr_i), DDR_A (ddr_j)) + && vect_same_range_drs (DDR_B (ddr_i), DDR_B (ddr_j))) + || (vect_same_range_drs (DDR_A (ddr_i), DDR_B (ddr_j)) + && vect_same_range_drs (DDR_B (ddr_i), DDR_A (ddr_j)))) + return true; + else + return false; +} + +/* Insert DDR into LOOP_VINFO list of ddrs that may alias and need to be + tested at run-time. Return TRUE if DDR was successfully inserted. + Return false if versioning is not supported. */ + +static bool +vect_mark_for_runtime_alias_test (ddr_p ddr, loop_vec_info loop_vinfo) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + + if ((unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS) == 0) + return false; + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "mark for run-time aliasing test between "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_A (ddr))); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_B (ddr))); + } + + if (optimize_loop_nest_for_size_p (loop)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "versioning not supported when optimizing for size."); + return false; + } + + /* FORNOW: We don't support versioning with outer-loop vectorization. */ + if (loop->inner) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "versioning not yet supported for outer-loops."); + return false; + } + + /* FORNOW: We don't support creating runtime alias tests for non-constant + step. */ + if (TREE_CODE (DR_STEP (DDR_A (ddr))) != INTEGER_CST + || TREE_CODE (DR_STEP (DDR_B (ddr))) != INTEGER_CST) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "versioning not yet supported for non-constant " + "step"); + return false; + } + + LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo).safe_push (ddr); + return true; +} + + +/* Function vect_analyze_data_ref_dependence. + + Return TRUE if there (might) exist a dependence between a memory-reference + DRA and a memory-reference DRB. When versioning for alias may check a + dependence at run-time, return FALSE. Adjust *MAX_VF according to + the data dependence. */ + +static bool +vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, + loop_vec_info loop_vinfo, int *max_vf) +{ + unsigned int i; + struct loop *loop = NULL; + struct data_reference *dra = DDR_A (ddr); + struct data_reference *drb = DDR_B (ddr); + stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); + stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb)); + lambda_vector dist_v; + unsigned int loop_depth; + + /* Don't bother to analyze statements marked as unvectorizable. */ + if (!STMT_VINFO_VECTORIZABLE (stmtinfo_a) + || !STMT_VINFO_VECTORIZABLE (stmtinfo_b)) + return false; + + if (DDR_ARE_DEPENDENT (ddr) == chrec_known) + { + /* Independent data accesses. */ + vect_check_interleaving (dra, drb); + return false; + } + + if (loop_vinfo) + loop = LOOP_VINFO_LOOP (loop_vinfo); + + if ((DR_IS_READ (dra) && DR_IS_READ (drb) && loop_vinfo) || dra == drb) + return false; + + if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) + { + gimple earlier_stmt; + + if (loop_vinfo) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "versioning for alias required: " + "can't determine dependence between "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, + DR_REF (dra)); + dump_printf (MSG_MISSED_OPTIMIZATION, " and "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, + DR_REF (drb)); + } + + /* Add to list of ddrs that need to be tested at run-time. */ + return !vect_mark_for_runtime_alias_test (ddr, loop_vinfo); + } + + /* When vectorizing a basic block unknown depnedence can still mean + grouped access. */ + if (vect_check_interleaving (dra, drb)) + return false; + + /* Read-read is OK (we need this check here, after checking for + interleaving). */ + if (DR_IS_READ (dra) && DR_IS_READ (drb)) + return false; + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "can't determine dependence between "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_MISSED_OPTIMIZATION, " and "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, DR_REF (drb)); + } + + /* We do not vectorize basic blocks with write-write dependencies. */ + if (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)) + return true; + + /* Check that it's not a load-after-store dependence. */ + earlier_stmt = get_earlier_stmt (DR_STMT (dra), DR_STMT (drb)); + if (DR_IS_WRITE (STMT_VINFO_DATA_REF (vinfo_for_stmt (earlier_stmt)))) + return true; + + return false; + } + + /* Versioning for alias is not yet supported for basic block SLP, and + dependence distance is unapplicable, hence, in case of known data + dependence, basic block vectorization is impossible for now. */ + if (!loop_vinfo) + { + if (dra != drb && vect_check_interleaving (dra, drb)) + return false; + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "determined dependence between "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + + /* Do not vectorize basic blcoks with write-write dependences. */ + if (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)) + return true; + + /* Check if this dependence is allowed in basic block vectorization. */ + return vect_drs_dependent_in_basic_block (dra, drb); + } + + /* Loop-based vectorization and known data dependence. */ + if (DDR_NUM_DIST_VECTS (ddr) == 0) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "versioning for alias required: " + "bad dist vector for "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_MISSED_OPTIMIZATION, " and "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, DR_REF (drb)); + } + /* Add to list of ddrs that need to be tested at run-time. */ + return !vect_mark_for_runtime_alias_test (ddr, loop_vinfo); + } + + loop_depth = index_in_loop_nest (loop->num, DDR_LOOP_NEST (ddr)); + FOR_EACH_VEC_ELT (DDR_DIST_VECTS (ddr), i, dist_v) + { + int dist = dist_v[loop_depth]; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "dependence distance = %d.", dist); + + if (dist == 0) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "dependence distance == 0 between "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + + /* For interleaving, mark that there is a read-write dependency if + necessary. We check before that one of the data-refs is store. */ + if (DR_IS_READ (dra)) + GROUP_READ_WRITE_DEPENDENCE (stmtinfo_a) = true; + else + { + if (DR_IS_READ (drb)) + GROUP_READ_WRITE_DEPENDENCE (stmtinfo_b) = true; + } + + continue; + } + + if (dist > 0 && DDR_REVERSED_P (ddr)) + { + /* If DDR_REVERSED_P the order of the data-refs in DDR was + reversed (to make distance vector positive), and the actual + distance is negative. */ + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "dependence distance negative."); + /* Record a negative dependence distance to later limit the + amount of stmt copying / unrolling we can perform. + Only need to handle read-after-write dependence. */ + if (DR_IS_READ (drb) + && (STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) == 0 + || STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) > (unsigned)dist)) + STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) = dist; + continue; + } + + if (abs (dist) >= 2 + && abs (dist) < *max_vf) + { + /* The dependence distance requires reduction of the maximal + vectorization factor. */ + *max_vf = abs (dist); + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "adjusting maximal vectorization factor to %i", + *max_vf); + } + + if (abs (dist) >= *max_vf) + { + /* Dependence distance does not create dependence, as far as + vectorization is concerned, in this case. */ + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "dependence distance >= VF."); + continue; + } + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized, possible dependence " + "between data-refs "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + + return true; + } + + return false; +} + +/* Function vect_analyze_data_ref_dependences. + + Examine all the data references in the loop, and make sure there do not + exist any data dependences between them. Set *MAX_VF according to + the maximum vectorization factor the data dependences allow. */ + +bool +vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo, + bb_vec_info bb_vinfo, int *max_vf) +{ + unsigned int i; + vec<ddr_p> ddrs = vNULL; + struct data_dependence_relation *ddr; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_analyze_dependences ==="); + if (loop_vinfo) + ddrs = LOOP_VINFO_DDRS (loop_vinfo); + else + ddrs = BB_VINFO_DDRS (bb_vinfo); + + FOR_EACH_VEC_ELT (ddrs, i, ddr) + if (vect_analyze_data_ref_dependence (ddr, loop_vinfo, max_vf)) + return false; + + return true; +} + + +/* Function vect_compute_data_ref_alignment + + Compute the misalignment of the data reference DR. + + Output: + 1. If during the misalignment computation it is found that the data reference + cannot be vectorized then false is returned. + 2. DR_MISALIGNMENT (DR) is defined. + + FOR NOW: No analysis is actually performed. Misalignment is calculated + only for trivial cases. TODO. */ + +static bool +vect_compute_data_ref_alignment (struct data_reference *dr) +{ + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + struct loop *loop = NULL; + tree ref = DR_REF (dr); + tree vectype; + tree base, base_addr; + bool base_aligned; + tree misalign; + tree aligned_to, alignment; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "vect_compute_data_ref_alignment:"); + + if (loop_vinfo) + loop = LOOP_VINFO_LOOP (loop_vinfo); + + /* Initialize misalignment to unknown. */ + SET_DR_MISALIGNMENT (dr, -1); + + /* Strided loads perform only component accesses, misalignment information + is irrelevant for them. */ + if (STMT_VINFO_STRIDE_LOAD_P (stmt_info)) + return true; + + misalign = DR_INIT (dr); + aligned_to = DR_ALIGNED_TO (dr); + base_addr = DR_BASE_ADDRESS (dr); + vectype = STMT_VINFO_VECTYPE (stmt_info); + + /* In case the dataref is in an inner-loop of the loop that is being + vectorized (LOOP), we use the base and misalignment information + relative to the outer-loop (LOOP). This is ok only if the misalignment + stays the same throughout the execution of the inner-loop, which is why + we have to check that the stride of the dataref in the inner-loop evenly + divides by the vector size. */ + if (loop && nested_in_vect_loop_p (loop, stmt)) + { + tree step = DR_STEP (dr); + HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); + + if (dr_step % GET_MODE_SIZE (TYPE_MODE (vectype)) == 0) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "inner step divides the vector-size."); + misalign = STMT_VINFO_DR_INIT (stmt_info); + aligned_to = STMT_VINFO_DR_ALIGNED_TO (stmt_info); + base_addr = STMT_VINFO_DR_BASE_ADDRESS (stmt_info); + } + else + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "inner step doesn't divide the vector-size."); + misalign = NULL_TREE; + } + } + + /* Similarly, if we're doing basic-block vectorization, we can only use + base and misalignment information relative to an innermost loop if the + misalignment stays the same throughout the execution of the loop. + As above, this is the case if the stride of the dataref evenly divides + by the vector size. */ + if (!loop) + { + tree step = DR_STEP (dr); + HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); + + if (dr_step % GET_MODE_SIZE (TYPE_MODE (vectype)) != 0) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "SLP: step doesn't divide the vector-size."); + misalign = NULL_TREE; + } + } + + base = build_fold_indirect_ref (base_addr); + alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT); + + if ((aligned_to && tree_int_cst_compare (aligned_to, alignment) < 0) + || !misalign) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Unknown alignment for access: "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, base); + } + return true; + } + + if ((DECL_P (base) + && tree_int_cst_compare (ssize_int (DECL_ALIGN_UNIT (base)), + alignment) >= 0) + || (TREE_CODE (base_addr) == SSA_NAME + && tree_int_cst_compare (ssize_int (TYPE_ALIGN_UNIT (TREE_TYPE ( + TREE_TYPE (base_addr)))), + alignment) >= 0) + || (get_pointer_alignment (base_addr) >= TYPE_ALIGN (vectype))) + base_aligned = true; + else + base_aligned = false; + + if (!base_aligned) + { + /* Do not change the alignment of global variables here if + flag_section_anchors is enabled as we already generated + RTL for other functions. Most global variables should + have been aligned during the IPA increase_alignment pass. */ + if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype)) + || (TREE_STATIC (base) && flag_section_anchors)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "can't force alignment of ref: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); + } + return true; + } + + /* Force the alignment of the decl. + NOTE: This is the only change to the code we make during + the analysis phase, before deciding to vectorize the loop. */ + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, "force alignment of "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); + } + + DECL_ALIGN (base) = TYPE_ALIGN (vectype); + DECL_USER_ALIGN (base) = 1; + } + + /* At this point we assume that the base is aligned. */ + gcc_assert (base_aligned + || (TREE_CODE (base) == VAR_DECL + && DECL_ALIGN (base) >= TYPE_ALIGN (vectype))); + + /* If this is a backward running DR then first access in the larger + vectype actually is N-1 elements before the address in the DR. + Adjust misalign accordingly. */ + if (tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0) + { + tree offset = ssize_int (TYPE_VECTOR_SUBPARTS (vectype) - 1); + /* DR_STEP(dr) is the same as -TYPE_SIZE of the scalar type, + otherwise we wouldn't be here. */ + offset = fold_build2 (MULT_EXPR, ssizetype, offset, DR_STEP (dr)); + /* PLUS because DR_STEP was negative. */ + misalign = size_binop (PLUS_EXPR, misalign, offset); + } + + /* Modulo alignment. */ + misalign = size_binop (FLOOR_MOD_EXPR, misalign, alignment); + + if (!host_integerp (misalign, 1)) + { + /* Negative or overflowed misalignment value. */ + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "unexpected misalign value"); + return false; + } + + SET_DR_MISALIGNMENT (dr, TREE_INT_CST_LOW (misalign)); + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "misalign = %d bytes of ref ", DR_MISALIGNMENT (dr)); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, ref); + } + + return true; +} + + +/* Function vect_compute_data_refs_alignment + + Compute the misalignment of data references in the loop. + Return FALSE if a data reference is found that cannot be vectorized. */ + +static bool +vect_compute_data_refs_alignment (loop_vec_info loop_vinfo, + bb_vec_info bb_vinfo) +{ + vec<data_reference_p> datarefs; + struct data_reference *dr; + unsigned int i; + + if (loop_vinfo) + datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + else + datarefs = BB_VINFO_DATAREFS (bb_vinfo); + + FOR_EACH_VEC_ELT (datarefs, i, dr) + if (STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) + && !vect_compute_data_ref_alignment (dr)) + { + if (bb_vinfo) + { + /* Mark unsupported statement as unvectorizable. */ + STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) = false; + continue; + } + else + return false; + } + + return true; +} + + +/* Function vect_update_misalignment_for_peel + + DR - the data reference whose misalignment is to be adjusted. + DR_PEEL - the data reference whose misalignment is being made + zero in the vector loop by the peel. + NPEEL - the number of iterations in the peel loop if the misalignment + of DR_PEEL is known at compile time. */ + +static void +vect_update_misalignment_for_peel (struct data_reference *dr, + struct data_reference *dr_peel, int npeel) +{ + unsigned int i; + vec<dr_p> same_align_drs; + struct data_reference *current_dr; + int dr_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr)))); + int dr_peel_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr_peel)))); + stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr)); + stmt_vec_info peel_stmt_info = vinfo_for_stmt (DR_STMT (dr_peel)); + + /* For interleaved data accesses the step in the loop must be multiplied by + the size of the interleaving group. */ + if (STMT_VINFO_GROUPED_ACCESS (stmt_info)) + dr_size *= GROUP_SIZE (vinfo_for_stmt (GROUP_FIRST_ELEMENT (stmt_info))); + if (STMT_VINFO_GROUPED_ACCESS (peel_stmt_info)) + dr_peel_size *= GROUP_SIZE (peel_stmt_info); + + /* It can be assumed that the data refs with the same alignment as dr_peel + are aligned in the vector loop. */ + same_align_drs + = STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr_peel))); + FOR_EACH_VEC_ELT (same_align_drs, i, current_dr) + { + if (current_dr != dr) + continue; + gcc_assert (DR_MISALIGNMENT (dr) / dr_size == + DR_MISALIGNMENT (dr_peel) / dr_peel_size); + SET_DR_MISALIGNMENT (dr, 0); + return; + } + + if (known_alignment_for_access_p (dr) + && known_alignment_for_access_p (dr_peel)) + { + bool negative = tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0; + int misal = DR_MISALIGNMENT (dr); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + misal += negative ? -npeel * dr_size : npeel * dr_size; + misal &= (TYPE_ALIGN (vectype) / BITS_PER_UNIT) - 1; + SET_DR_MISALIGNMENT (dr, misal); + return; + } + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, "Setting misalignment to -1."); + SET_DR_MISALIGNMENT (dr, -1); +} + + +/* Function vect_verify_datarefs_alignment + + Return TRUE if all data references in the loop can be + handled with respect to alignment. */ + +bool +vect_verify_datarefs_alignment (loop_vec_info loop_vinfo, bb_vec_info bb_vinfo) +{ + vec<data_reference_p> datarefs; + struct data_reference *dr; + enum dr_alignment_support supportable_dr_alignment; + unsigned int i; + + if (loop_vinfo) + datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + else + datarefs = BB_VINFO_DATAREFS (bb_vinfo); + + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + + if (!STMT_VINFO_RELEVANT_P (stmt_info)) + continue; + + /* For interleaving, only the alignment of the first access matters. + Skip statements marked as not vectorizable. */ + if ((STMT_VINFO_GROUPED_ACCESS (stmt_info) + && GROUP_FIRST_ELEMENT (stmt_info) != stmt) + || !STMT_VINFO_VECTORIZABLE (stmt_info)) + continue; + + /* Strided loads perform only component accesses, alignment is + irrelevant for them. */ + if (STMT_VINFO_STRIDE_LOAD_P (stmt_info)) + continue; + + supportable_dr_alignment = vect_supportable_dr_alignment (dr, false); + if (!supportable_dr_alignment) + { + if (dump_enabled_p ()) + { + if (DR_IS_READ (dr)) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: unsupported unaligned load."); + else + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: unsupported unaligned " + "store."); + + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, + DR_REF (dr)); + } + return false; + } + if (supportable_dr_alignment != dr_aligned && dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Vectorizing an unaligned access."); + } + return true; +} + +/* Given an memory reference EXP return whether its alignment is less + than its size. */ + +static bool +not_size_aligned (tree exp) +{ + if (!host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1)) + return true; + + return (TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp))) + > get_object_alignment (exp)); +} + +/* Function vector_alignment_reachable_p + + Return true if vector alignment for DR is reachable by peeling + a few loop iterations. Return false otherwise. */ + +static bool +vector_alignment_reachable_p (struct data_reference *dr) +{ + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + + if (STMT_VINFO_GROUPED_ACCESS (stmt_info)) + { + /* For interleaved access we peel only if number of iterations in + the prolog loop ({VF - misalignment}), is a multiple of the + number of the interleaved accesses. */ + int elem_size, mis_in_elements; + int nelements = TYPE_VECTOR_SUBPARTS (vectype); + + /* FORNOW: handle only known alignment. */ + if (!known_alignment_for_access_p (dr)) + return false; + + elem_size = GET_MODE_SIZE (TYPE_MODE (vectype)) / nelements; + mis_in_elements = DR_MISALIGNMENT (dr) / elem_size; + + if ((nelements - mis_in_elements) % GROUP_SIZE (stmt_info)) + return false; + } + + /* If misalignment is known at the compile time then allow peeling + only if natural alignment is reachable through peeling. */ + if (known_alignment_for_access_p (dr) && !aligned_access_p (dr)) + { + HOST_WIDE_INT elmsize = + int_cst_value (TYPE_SIZE_UNIT (TREE_TYPE (vectype))); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "data size =" HOST_WIDE_INT_PRINT_DEC, elmsize); + dump_printf (MSG_NOTE, + ". misalignment = %d. ", DR_MISALIGNMENT (dr)); + } + if (DR_MISALIGNMENT (dr) % elmsize) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "data size does not divide the misalignment.\n"); + return false; + } + } + + if (!known_alignment_for_access_p (dr)) + { + tree type = TREE_TYPE (DR_REF (dr)); + bool is_packed = not_size_aligned (DR_REF (dr)); + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Unknown misalignment, is_packed = %d",is_packed); + if (targetm.vectorize.vector_alignment_reachable (type, is_packed)) + return true; + else + return false; + } + + return true; +} + + +/* Calculate the cost of the memory access represented by DR. */ + +static void +vect_get_data_access_cost (struct data_reference *dr, + unsigned int *inside_cost, + unsigned int *outside_cost, + stmt_vector_for_cost *body_cost_vec) +{ + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + int nunits = TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info)); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); + int ncopies = vf / nunits; + + if (DR_IS_READ (dr)) + vect_get_load_cost (dr, ncopies, true, inside_cost, outside_cost, + NULL, body_cost_vec, false); + else + vect_get_store_cost (dr, ncopies, inside_cost, body_cost_vec); + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "vect_get_data_access_cost: inside_cost = %d, " + "outside_cost = %d.", *inside_cost, *outside_cost); +} + + +static hashval_t +vect_peeling_hash (const void *elem) +{ + const struct _vect_peel_info *peel_info; + + peel_info = (const struct _vect_peel_info *) elem; + return (hashval_t) peel_info->npeel; +} + + +static int +vect_peeling_hash_eq (const void *elem1, const void *elem2) +{ + const struct _vect_peel_info *a, *b; + + a = (const struct _vect_peel_info *) elem1; + b = (const struct _vect_peel_info *) elem2; + return (a->npeel == b->npeel); +} + + +/* Insert DR into peeling hash table with NPEEL as key. */ + +static void +vect_peeling_hash_insert (loop_vec_info loop_vinfo, struct data_reference *dr, + int npeel) +{ + struct _vect_peel_info elem, *slot; + void **new_slot; + bool supportable_dr_alignment = vect_supportable_dr_alignment (dr, true); + + elem.npeel = npeel; + slot = (vect_peel_info) htab_find (LOOP_VINFO_PEELING_HTAB (loop_vinfo), + &elem); + if (slot) + slot->count++; + else + { + slot = XNEW (struct _vect_peel_info); + slot->npeel = npeel; + slot->dr = dr; + slot->count = 1; + new_slot = htab_find_slot (LOOP_VINFO_PEELING_HTAB (loop_vinfo), slot, + INSERT); + *new_slot = slot; + } + + if (!supportable_dr_alignment && !flag_vect_cost_model) + slot->count += VECT_MAX_COST; +} + + +/* Traverse peeling hash table to find peeling option that aligns maximum + number of data accesses. */ + +static int +vect_peeling_hash_get_most_frequent (void **slot, void *data) +{ + vect_peel_info elem = (vect_peel_info) *slot; + vect_peel_extended_info max = (vect_peel_extended_info) data; + + if (elem->count > max->peel_info.count + || (elem->count == max->peel_info.count + && max->peel_info.npeel > elem->npeel)) + { + max->peel_info.npeel = elem->npeel; + max->peel_info.count = elem->count; + max->peel_info.dr = elem->dr; + } + + return 1; +} + + +/* Traverse peeling hash table and calculate cost for each peeling option. + Find the one with the lowest cost. */ + +static int +vect_peeling_hash_get_lowest_cost (void **slot, void *data) +{ + vect_peel_info elem = (vect_peel_info) *slot; + vect_peel_extended_info min = (vect_peel_extended_info) data; + int save_misalignment, dummy; + unsigned int inside_cost = 0, outside_cost = 0, i; + gimple stmt = DR_STMT (elem->dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + vec<data_reference_p> datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + struct data_reference *dr; + stmt_vector_for_cost prologue_cost_vec, body_cost_vec, epilogue_cost_vec; + int single_iter_cost; + + prologue_cost_vec.create (2); + body_cost_vec.create (2); + epilogue_cost_vec.create (2); + + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + stmt = DR_STMT (dr); + stmt_info = vinfo_for_stmt (stmt); + /* For interleaving, only the alignment of the first access + matters. */ + if (STMT_VINFO_GROUPED_ACCESS (stmt_info) + && GROUP_FIRST_ELEMENT (stmt_info) != stmt) + continue; + + save_misalignment = DR_MISALIGNMENT (dr); + vect_update_misalignment_for_peel (dr, elem->dr, elem->npeel); + vect_get_data_access_cost (dr, &inside_cost, &outside_cost, + &body_cost_vec); + SET_DR_MISALIGNMENT (dr, save_misalignment); + } + + single_iter_cost = vect_get_single_scalar_iteration_cost (loop_vinfo); + outside_cost += vect_get_known_peeling_cost (loop_vinfo, elem->npeel, + &dummy, single_iter_cost, + &prologue_cost_vec, + &epilogue_cost_vec); + + /* Prologue and epilogue costs are added to the target model later. + These costs depend only on the scalar iteration cost, the + number of peeling iterations finally chosen, and the number of + misaligned statements. So discard the information found here. */ + prologue_cost_vec.release (); + epilogue_cost_vec.release (); + + if (inside_cost < min->inside_cost + || (inside_cost == min->inside_cost && outside_cost < min->outside_cost)) + { + min->inside_cost = inside_cost; + min->outside_cost = outside_cost; + min->body_cost_vec.release (); + min->body_cost_vec = body_cost_vec; + min->peel_info.dr = elem->dr; + min->peel_info.npeel = elem->npeel; + } + else + body_cost_vec.release (); + + return 1; +} + + +/* Choose best peeling option by traversing peeling hash table and either + choosing an option with the lowest cost (if cost model is enabled) or the + option that aligns as many accesses as possible. */ + +static struct data_reference * +vect_peeling_hash_choose_best_peeling (loop_vec_info loop_vinfo, + unsigned int *npeel, + stmt_vector_for_cost *body_cost_vec) +{ + struct _vect_peel_extended_info res; + + res.peel_info.dr = NULL; + res.body_cost_vec = stmt_vector_for_cost(); + + if (flag_vect_cost_model) + { + res.inside_cost = INT_MAX; + res.outside_cost = INT_MAX; + htab_traverse (LOOP_VINFO_PEELING_HTAB (loop_vinfo), + vect_peeling_hash_get_lowest_cost, &res); + } + else + { + res.peel_info.count = 0; + htab_traverse (LOOP_VINFO_PEELING_HTAB (loop_vinfo), + vect_peeling_hash_get_most_frequent, &res); + } + + *npeel = res.peel_info.npeel; + *body_cost_vec = res.body_cost_vec; + return res.peel_info.dr; +} + + +/* Function vect_enhance_data_refs_alignment + + This pass will use loop versioning and loop peeling in order to enhance + the alignment of data references in the loop. + + FOR NOW: we assume that whatever versioning/peeling takes place, only the + original loop is to be vectorized. Any other loops that are created by + the transformations performed in this pass - are not supposed to be + vectorized. This restriction will be relaxed. + + This pass will require a cost model to guide it whether to apply peeling + or versioning or a combination of the two. For example, the scheme that + intel uses when given a loop with several memory accesses, is as follows: + choose one memory access ('p') which alignment you want to force by doing + peeling. Then, either (1) generate a loop in which 'p' is aligned and all + other accesses are not necessarily aligned, or (2) use loop versioning to + generate one loop in which all accesses are aligned, and another loop in + which only 'p' is necessarily aligned. + + ("Automatic Intra-Register Vectorization for the Intel Architecture", + Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International + Journal of Parallel Programming, Vol. 30, No. 2, April 2002.) + + Devising a cost model is the most critical aspect of this work. It will + guide us on which access to peel for, whether to use loop versioning, how + many versions to create, etc. The cost model will probably consist of + generic considerations as well as target specific considerations (on + powerpc for example, misaligned stores are more painful than misaligned + loads). + + Here are the general steps involved in alignment enhancements: + + -- original loop, before alignment analysis: + for (i=0; i<N; i++){ + x = q[i]; # DR_MISALIGNMENT(q) = unknown + p[i] = y; # DR_MISALIGNMENT(p) = unknown + } + + -- After vect_compute_data_refs_alignment: + for (i=0; i<N; i++){ + x = q[i]; # DR_MISALIGNMENT(q) = 3 + p[i] = y; # DR_MISALIGNMENT(p) = unknown + } + + -- Possibility 1: we do loop versioning: + if (p is aligned) { + for (i=0; i<N; i++){ # loop 1A + x = q[i]; # DR_MISALIGNMENT(q) = 3 + p[i] = y; # DR_MISALIGNMENT(p) = 0 + } + } + else { + for (i=0; i<N; i++){ # loop 1B + x = q[i]; # DR_MISALIGNMENT(q) = 3 + p[i] = y; # DR_MISALIGNMENT(p) = unaligned + } + } + + -- Possibility 2: we do loop peeling: + for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized). + x = q[i]; + p[i] = y; + } + for (i = 3; i < N; i++){ # loop 2A + x = q[i]; # DR_MISALIGNMENT(q) = 0 + p[i] = y; # DR_MISALIGNMENT(p) = unknown + } + + -- Possibility 3: combination of loop peeling and versioning: + for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized). + x = q[i]; + p[i] = y; + } + if (p is aligned) { + for (i = 3; i<N; i++){ # loop 3A + x = q[i]; # DR_MISALIGNMENT(q) = 0 + p[i] = y; # DR_MISALIGNMENT(p) = 0 + } + } + else { + for (i = 3; i<N; i++){ # loop 3B + x = q[i]; # DR_MISALIGNMENT(q) = 0 + p[i] = y; # DR_MISALIGNMENT(p) = unaligned + } + } + + These loops are later passed to loop_transform to be vectorized. The + vectorizer will use the alignment information to guide the transformation + (whether to generate regular loads/stores, or with special handling for + misalignment). */ + +bool +vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo) +{ + vec<data_reference_p> datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + enum dr_alignment_support supportable_dr_alignment; + struct data_reference *dr0 = NULL, *first_store = NULL; + struct data_reference *dr; + unsigned int i, j; + bool do_peeling = false; + bool do_versioning = false; + bool stat; + gimple stmt; + stmt_vec_info stmt_info; + int vect_versioning_for_alias_required; + unsigned int npeel = 0; + bool all_misalignments_unknown = true; + unsigned int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); + unsigned possible_npeel_number = 1; + tree vectype; + unsigned int nelements, mis, same_align_drs_max = 0; + stmt_vector_for_cost body_cost_vec = stmt_vector_for_cost(); + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_enhance_data_refs_alignment ==="); + + /* While cost model enhancements are expected in the future, the high level + view of the code at this time is as follows: + + A) If there is a misaligned access then see if peeling to align + this access can make all data references satisfy + vect_supportable_dr_alignment. If so, update data structures + as needed and return true. + + B) If peeling wasn't possible and there is a data reference with an + unknown misalignment that does not satisfy vect_supportable_dr_alignment + then see if loop versioning checks can be used to make all data + references satisfy vect_supportable_dr_alignment. If so, update + data structures as needed and return true. + + C) If neither peeling nor versioning were successful then return false if + any data reference does not satisfy vect_supportable_dr_alignment. + + D) Return true (all data references satisfy vect_supportable_dr_alignment). + + Note, Possibility 3 above (which is peeling and versioning together) is not + being done at this time. */ + + /* (1) Peeling to force alignment. */ + + /* (1.1) Decide whether to perform peeling, and how many iterations to peel: + Considerations: + + How many accesses will become aligned due to the peeling + - How many accesses will become unaligned due to the peeling, + and the cost of misaligned accesses. + - The cost of peeling (the extra runtime checks, the increase + in code size). */ + + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + stmt = DR_STMT (dr); + stmt_info = vinfo_for_stmt (stmt); + + if (!STMT_VINFO_RELEVANT_P (stmt_info)) + continue; + + /* For interleaving, only the alignment of the first access + matters. */ + if (STMT_VINFO_GROUPED_ACCESS (stmt_info) + && GROUP_FIRST_ELEMENT (stmt_info) != stmt) + continue; + + /* For invariant accesses there is nothing to enhance. */ + if (integer_zerop (DR_STEP (dr))) + continue; + + /* Strided loads perform only component accesses, alignment is + irrelevant for them. */ + if (STMT_VINFO_STRIDE_LOAD_P (stmt_info)) + continue; + + supportable_dr_alignment = vect_supportable_dr_alignment (dr, true); + do_peeling = vector_alignment_reachable_p (dr); + if (do_peeling) + { + if (known_alignment_for_access_p (dr)) + { + unsigned int npeel_tmp; + bool negative = tree_int_cst_compare (DR_STEP (dr), + size_zero_node) < 0; + + /* Save info about DR in the hash table. */ + if (!LOOP_VINFO_PEELING_HTAB (loop_vinfo)) + LOOP_VINFO_PEELING_HTAB (loop_vinfo) = + htab_create (1, vect_peeling_hash, + vect_peeling_hash_eq, free); + + vectype = STMT_VINFO_VECTYPE (stmt_info); + nelements = TYPE_VECTOR_SUBPARTS (vectype); + mis = DR_MISALIGNMENT (dr) / GET_MODE_SIZE (TYPE_MODE ( + TREE_TYPE (DR_REF (dr)))); + npeel_tmp = (negative + ? (mis - nelements) : (nelements - mis)) + & (nelements - 1); + + /* For multiple types, it is possible that the bigger type access + will have more than one peeling option. E.g., a loop with two + types: one of size (vector size / 4), and the other one of + size (vector size / 8). Vectorization factor will 8. If both + access are misaligned by 3, the first one needs one scalar + iteration to be aligned, and the second one needs 5. But the + the first one will be aligned also by peeling 5 scalar + iterations, and in that case both accesses will be aligned. + Hence, except for the immediate peeling amount, we also want + to try to add full vector size, while we don't exceed + vectorization factor. + We do this automtically for cost model, since we calculate cost + for every peeling option. */ + if (!flag_vect_cost_model) + possible_npeel_number = vf /nelements; + + /* Handle the aligned case. We may decide to align some other + access, making DR unaligned. */ + if (DR_MISALIGNMENT (dr) == 0) + { + npeel_tmp = 0; + if (!flag_vect_cost_model) + possible_npeel_number++; + } + + for (j = 0; j < possible_npeel_number; j++) + { + gcc_assert (npeel_tmp <= vf); + vect_peeling_hash_insert (loop_vinfo, dr, npeel_tmp); + npeel_tmp += nelements; + } + + all_misalignments_unknown = false; + /* Data-ref that was chosen for the case that all the + misalignments are unknown is not relevant anymore, since we + have a data-ref with known alignment. */ + dr0 = NULL; + } + else + { + /* If we don't know all the misalignment values, we prefer + peeling for data-ref that has maximum number of data-refs + with the same alignment, unless the target prefers to align + stores over load. */ + if (all_misalignments_unknown) + { + if (same_align_drs_max + < STMT_VINFO_SAME_ALIGN_REFS (stmt_info).length () + || !dr0) + { + same_align_drs_max + = STMT_VINFO_SAME_ALIGN_REFS (stmt_info).length (); + dr0 = dr; + } + + if (!first_store && DR_IS_WRITE (dr)) + first_store = dr; + } + + /* If there are both known and unknown misaligned accesses in the + loop, we choose peeling amount according to the known + accesses. */ + + + if (!supportable_dr_alignment) + { + dr0 = dr; + if (!first_store && DR_IS_WRITE (dr)) + first_store = dr; + } + } + } + else + { + if (!aligned_access_p (dr)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "vector alignment may not be reachable"); + break; + } + } + } + + vect_versioning_for_alias_required + = LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo); + + /* Temporarily, if versioning for alias is required, we disable peeling + until we support peeling and versioning. Often peeling for alignment + will require peeling for loop-bound, which in turn requires that we + know how to adjust the loop ivs after the loop. */ + if (vect_versioning_for_alias_required + || !vect_can_advance_ivs_p (loop_vinfo) + || !slpeel_can_duplicate_loop_p (loop, single_exit (loop))) + do_peeling = false; + + if (do_peeling && all_misalignments_unknown + && vect_supportable_dr_alignment (dr0, false)) + { + + /* Check if the target requires to prefer stores over loads, i.e., if + misaligned stores are more expensive than misaligned loads (taking + drs with same alignment into account). */ + if (first_store && DR_IS_READ (dr0)) + { + unsigned int load_inside_cost = 0, load_outside_cost = 0; + unsigned int store_inside_cost = 0, store_outside_cost = 0; + unsigned int load_inside_penalty = 0, load_outside_penalty = 0; + unsigned int store_inside_penalty = 0, store_outside_penalty = 0; + stmt_vector_for_cost dummy; + dummy.create (2); + + vect_get_data_access_cost (dr0, &load_inside_cost, &load_outside_cost, + &dummy); + vect_get_data_access_cost (first_store, &store_inside_cost, + &store_outside_cost, &dummy); + + dummy.release (); + + /* Calculate the penalty for leaving FIRST_STORE unaligned (by + aligning the load DR0). */ + load_inside_penalty = store_inside_cost; + load_outside_penalty = store_outside_cost; + for (i = 0; + STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt ( + DR_STMT (first_store))).iterate (i, &dr); + i++) + if (DR_IS_READ (dr)) + { + load_inside_penalty += load_inside_cost; + load_outside_penalty += load_outside_cost; + } + else + { + load_inside_penalty += store_inside_cost; + load_outside_penalty += store_outside_cost; + } + + /* Calculate the penalty for leaving DR0 unaligned (by + aligning the FIRST_STORE). */ + store_inside_penalty = load_inside_cost; + store_outside_penalty = load_outside_cost; + for (i = 0; + STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt ( + DR_STMT (dr0))).iterate (i, &dr); + i++) + if (DR_IS_READ (dr)) + { + store_inside_penalty += load_inside_cost; + store_outside_penalty += load_outside_cost; + } + else + { + store_inside_penalty += store_inside_cost; + store_outside_penalty += store_outside_cost; + } + + if (load_inside_penalty > store_inside_penalty + || (load_inside_penalty == store_inside_penalty + && load_outside_penalty > store_outside_penalty)) + dr0 = first_store; + } + + /* In case there are only loads with different unknown misalignments, use + peeling only if it may help to align other accesses in the loop. */ + if (!first_store + && !STMT_VINFO_SAME_ALIGN_REFS ( + vinfo_for_stmt (DR_STMT (dr0))).length () + && vect_supportable_dr_alignment (dr0, false) + != dr_unaligned_supported) + do_peeling = false; + } + + if (do_peeling && !dr0) + { + /* Peeling is possible, but there is no data access that is not supported + unless aligned. So we try to choose the best possible peeling. */ + + /* We should get here only if there are drs with known misalignment. */ + gcc_assert (!all_misalignments_unknown); + + /* Choose the best peeling from the hash table. */ + dr0 = vect_peeling_hash_choose_best_peeling (loop_vinfo, &npeel, + &body_cost_vec); + if (!dr0 || !npeel) + do_peeling = false; + } + + if (do_peeling) + { + stmt = DR_STMT (dr0); + stmt_info = vinfo_for_stmt (stmt); + vectype = STMT_VINFO_VECTYPE (stmt_info); + nelements = TYPE_VECTOR_SUBPARTS (vectype); + + if (known_alignment_for_access_p (dr0)) + { + bool negative = tree_int_cst_compare (DR_STEP (dr0), + size_zero_node) < 0; + if (!npeel) + { + /* Since it's known at compile time, compute the number of + iterations in the peeled loop (the peeling factor) for use in + updating DR_MISALIGNMENT values. The peeling factor is the + vectorization factor minus the misalignment as an element + count. */ + mis = DR_MISALIGNMENT (dr0); + mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0)))); + npeel = ((negative ? mis - nelements : nelements - mis) + & (nelements - 1)); + } + + /* For interleaved data access every iteration accesses all the + members of the group, therefore we divide the number of iterations + by the group size. */ + stmt_info = vinfo_for_stmt (DR_STMT (dr0)); + if (STMT_VINFO_GROUPED_ACCESS (stmt_info)) + npeel /= GROUP_SIZE (stmt_info); + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Try peeling by %d", npeel); + } + + /* Ensure that all data refs can be vectorized after the peel. */ + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + int save_misalignment; + + if (dr == dr0) + continue; + + stmt = DR_STMT (dr); + stmt_info = vinfo_for_stmt (stmt); + /* For interleaving, only the alignment of the first access + matters. */ + if (STMT_VINFO_GROUPED_ACCESS (stmt_info) + && GROUP_FIRST_ELEMENT (stmt_info) != stmt) + continue; + + /* Strided loads perform only component accesses, alignment is + irrelevant for them. */ + if (STMT_VINFO_STRIDE_LOAD_P (stmt_info)) + continue; + + save_misalignment = DR_MISALIGNMENT (dr); + vect_update_misalignment_for_peel (dr, dr0, npeel); + supportable_dr_alignment = vect_supportable_dr_alignment (dr, false); + SET_DR_MISALIGNMENT (dr, save_misalignment); + + if (!supportable_dr_alignment) + { + do_peeling = false; + break; + } + } + + if (do_peeling && known_alignment_for_access_p (dr0) && npeel == 0) + { + stat = vect_verify_datarefs_alignment (loop_vinfo, NULL); + if (!stat) + do_peeling = false; + else + { + body_cost_vec.release (); + return stat; + } + } + + if (do_peeling) + { + stmt_info_for_cost *si; + void *data = LOOP_VINFO_TARGET_COST_DATA (loop_vinfo); + + /* (1.2) Update the DR_MISALIGNMENT of each data reference DR_i. + If the misalignment of DR_i is identical to that of dr0 then set + DR_MISALIGNMENT (DR_i) to zero. If the misalignment of DR_i and + dr0 are known at compile time then increment DR_MISALIGNMENT (DR_i) + by the peeling factor times the element size of DR_i (MOD the + vectorization factor times the size). Otherwise, the + misalignment of DR_i must be set to unknown. */ + FOR_EACH_VEC_ELT (datarefs, i, dr) + if (dr != dr0) + vect_update_misalignment_for_peel (dr, dr0, npeel); + + LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0; + if (npeel) + LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = npeel; + else + LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0); + SET_DR_MISALIGNMENT (dr0, 0); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "Alignment of access forced using peeling."); + dump_printf_loc (MSG_NOTE, vect_location, + "Peeling for alignment will be applied."); + } + /* We've delayed passing the inside-loop peeling costs to the + target cost model until we were sure peeling would happen. + Do so now. */ + if (body_cost_vec.exists ()) + { + FOR_EACH_VEC_ELT (body_cost_vec, i, si) + { + struct _stmt_vec_info *stmt_info + = si->stmt ? vinfo_for_stmt (si->stmt) : NULL; + (void) add_stmt_cost (data, si->count, si->kind, stmt_info, + si->misalign, vect_body); + } + body_cost_vec.release (); + } + + stat = vect_verify_datarefs_alignment (loop_vinfo, NULL); + gcc_assert (stat); + return stat; + } + } + + body_cost_vec.release (); + + /* (2) Versioning to force alignment. */ + + /* Try versioning if: + 1) flag_tree_vect_loop_version is TRUE + 2) optimize loop for speed + 3) there is at least one unsupported misaligned data ref with an unknown + misalignment, and + 4) all misaligned data refs with a known misalignment are supported, and + 5) the number of runtime alignment checks is within reason. */ + + do_versioning = + flag_tree_vect_loop_version + && optimize_loop_nest_for_speed_p (loop) + && (!loop->inner); /* FORNOW */ + + if (do_versioning) + { + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + stmt = DR_STMT (dr); + stmt_info = vinfo_for_stmt (stmt); + + /* For interleaving, only the alignment of the first access + matters. */ + if (aligned_access_p (dr) + || (STMT_VINFO_GROUPED_ACCESS (stmt_info) + && GROUP_FIRST_ELEMENT (stmt_info) != stmt)) + continue; + + /* Strided loads perform only component accesses, alignment is + irrelevant for them. */ + if (STMT_VINFO_STRIDE_LOAD_P (stmt_info)) + continue; + + supportable_dr_alignment = vect_supportable_dr_alignment (dr, false); + + if (!supportable_dr_alignment) + { + gimple stmt; + int mask; + tree vectype; + + if (known_alignment_for_access_p (dr) + || LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo).length () + >= (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS)) + { + do_versioning = false; + break; + } + + stmt = DR_STMT (dr); + vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); + gcc_assert (vectype); + + /* The rightmost bits of an aligned address must be zeros. + Construct the mask needed for this test. For example, + GET_MODE_SIZE for the vector mode V4SI is 16 bytes so the + mask must be 15 = 0xf. */ + mask = GET_MODE_SIZE (TYPE_MODE (vectype)) - 1; + + /* FORNOW: use the same mask to test all potentially unaligned + references in the loop. The vectorizer currently supports + a single vector size, see the reference to + GET_MODE_NUNITS (TYPE_MODE (vectype)) where the + vectorization factor is computed. */ + gcc_assert (!LOOP_VINFO_PTR_MASK (loop_vinfo) + || LOOP_VINFO_PTR_MASK (loop_vinfo) == mask); + LOOP_VINFO_PTR_MASK (loop_vinfo) = mask; + LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo).safe_push ( + DR_STMT (dr)); + } + } + + /* Versioning requires at least one misaligned data reference. */ + if (!LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo)) + do_versioning = false; + else if (!do_versioning) + LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo).truncate (0); + } + + if (do_versioning) + { + vec<gimple> may_misalign_stmts + = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo); + gimple stmt; + + /* It can now be assumed that the data references in the statements + in LOOP_VINFO_MAY_MISALIGN_STMTS will be aligned in the version + of the loop being vectorized. */ + FOR_EACH_VEC_ELT (may_misalign_stmts, i, stmt) + { + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + dr = STMT_VINFO_DATA_REF (stmt_info); + SET_DR_MISALIGNMENT (dr, 0); + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Alignment of access forced using versioning."); + } + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Versioning for alignment will be applied."); + + /* Peeling and versioning can't be done together at this time. */ + gcc_assert (! (do_peeling && do_versioning)); + + stat = vect_verify_datarefs_alignment (loop_vinfo, NULL); + gcc_assert (stat); + return stat; + } + + /* This point is reached if neither peeling nor versioning is being done. */ + gcc_assert (! (do_peeling || do_versioning)); + + stat = vect_verify_datarefs_alignment (loop_vinfo, NULL); + return stat; +} + + +/* Function vect_find_same_alignment_drs. + + Update group and alignment relations according to the chosen + vectorization factor. */ + +static void +vect_find_same_alignment_drs (struct data_dependence_relation *ddr, + loop_vec_info loop_vinfo) +{ + unsigned int i; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); + struct data_reference *dra = DDR_A (ddr); + struct data_reference *drb = DDR_B (ddr); + stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); + stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb)); + int dra_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dra)))); + int drb_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (drb)))); + lambda_vector dist_v; + unsigned int loop_depth; + + if (DDR_ARE_DEPENDENT (ddr) == chrec_known) + return; + + if (dra == drb) + return; + + if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) + return; + + /* Loop-based vectorization and known data dependence. */ + if (DDR_NUM_DIST_VECTS (ddr) == 0) + return; + + /* Data-dependence analysis reports a distance vector of zero + for data-references that overlap only in the first iteration + but have different sign step (see PR45764). + So as a sanity check require equal DR_STEP. */ + if (!operand_equal_p (DR_STEP (dra), DR_STEP (drb), 0)) + return; + + loop_depth = index_in_loop_nest (loop->num, DDR_LOOP_NEST (ddr)); + FOR_EACH_VEC_ELT (DDR_DIST_VECTS (ddr), i, dist_v) + { + int dist = dist_v[loop_depth]; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "dependence distance = %d.", dist); + + /* Same loop iteration. */ + if (dist == 0 + || (dist % vectorization_factor == 0 && dra_size == drb_size)) + { + /* Two references with distance zero have the same alignment. */ + STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a).safe_push (drb); + STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_b).safe_push (dra); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "accesses have the same alignment."); + dump_printf (MSG_NOTE, + "dependence distance modulo vf == 0 between "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dra)); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (drb)); + } + } + } +} + + +/* Function vect_analyze_data_refs_alignment + + Analyze the alignment of the data-references in the loop. + Return FALSE if a data reference is found that cannot be vectorized. */ + +bool +vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo, + bb_vec_info bb_vinfo) +{ + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_analyze_data_refs_alignment ==="); + + /* Mark groups of data references with same alignment using + data dependence information. */ + if (loop_vinfo) + { + vec<ddr_p> ddrs = LOOP_VINFO_DDRS (loop_vinfo); + struct data_dependence_relation *ddr; + unsigned int i; + + FOR_EACH_VEC_ELT (ddrs, i, ddr) + vect_find_same_alignment_drs (ddr, loop_vinfo); + } + + if (!vect_compute_data_refs_alignment (loop_vinfo, bb_vinfo)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: can't calculate alignment " + "for data ref."); + return false; + } + + return true; +} + + +/* Analyze groups of accesses: check that DR belongs to a group of + accesses of legal size, step, etc. Detect gaps, single element + interleaving, and other special cases. Set grouped access info. + Collect groups of strided stores for further use in SLP analysis. */ + +static bool +vect_analyze_group_access (struct data_reference *dr) +{ + tree step = DR_STEP (dr); + tree scalar_type = TREE_TYPE (DR_REF (dr)); + HOST_WIDE_INT type_size = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (scalar_type)); + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info); + HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); + HOST_WIDE_INT groupsize, last_accessed_element = 1; + bool slp_impossible = false; + struct loop *loop = NULL; + + if (loop_vinfo) + loop = LOOP_VINFO_LOOP (loop_vinfo); + + /* For interleaving, GROUPSIZE is STEP counted in elements, i.e., the + size of the interleaving group (including gaps). */ + groupsize = dr_step / type_size; + + /* Not consecutive access is possible only if it is a part of interleaving. */ + if (!GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt))) + { + /* Check if it this DR is a part of interleaving, and is a single + element of the group that is accessed in the loop. */ + + /* Gaps are supported only for loads. STEP must be a multiple of the type + size. The size of the group must be a power of 2. */ + if (DR_IS_READ (dr) + && (dr_step % type_size) == 0 + && groupsize > 0 + && exact_log2 (groupsize) != -1) + { + GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = stmt; + GROUP_SIZE (vinfo_for_stmt (stmt)) = groupsize; + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "Detected single element interleaving "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dr)); + dump_printf (MSG_NOTE, " step "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, step); + } + + if (loop_vinfo) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Data access with gaps requires scalar " + "epilogue loop"); + if (loop->inner) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Peeling for outer loop is not" + " supported"); + return false; + } + + LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) = true; + } + + return true; + } + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not consecutive access "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + /* Mark the statement as unvectorizable. */ + STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) = false; + return true; + } + + return false; + } + + if (GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) == stmt) + { + /* First stmt in the interleaving chain. Check the chain. */ + gimple next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (stmt)); + struct data_reference *data_ref = dr; + unsigned int count = 1; + tree next_step; + tree prev_init = DR_INIT (data_ref); + gimple prev = stmt; + HOST_WIDE_INT diff, count_in_bytes, gaps = 0; + + while (next) + { + /* Skip same data-refs. In case that two or more stmts share + data-ref (supported only for loads), we vectorize only the first + stmt, and the rest get their vectorized loads from the first + one. */ + if (!tree_int_cst_compare (DR_INIT (data_ref), + DR_INIT (STMT_VINFO_DATA_REF ( + vinfo_for_stmt (next))))) + { + if (DR_IS_WRITE (data_ref)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Two store stmts share the same dr."); + return false; + } + + /* Check that there is no load-store dependencies for this loads + to prevent a case of load-store-load to the same location. */ + if (GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (next)) + || GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (prev))) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "READ_WRITE dependence in interleaving."); + return false; + } + + /* For load use the same data-ref load. */ + GROUP_SAME_DR_STMT (vinfo_for_stmt (next)) = prev; + + prev = next; + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next)); + continue; + } + + prev = next; + + /* Check that all the accesses have the same STEP. */ + next_step = DR_STEP (STMT_VINFO_DATA_REF (vinfo_for_stmt (next))); + if (tree_int_cst_compare (step, next_step)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not consecutive access in interleaving"); + return false; + } + + data_ref = STMT_VINFO_DATA_REF (vinfo_for_stmt (next)); + /* Check that the distance between two accesses is equal to the type + size. Otherwise, we have gaps. */ + diff = (TREE_INT_CST_LOW (DR_INIT (data_ref)) + - TREE_INT_CST_LOW (prev_init)) / type_size; + if (diff != 1) + { + /* FORNOW: SLP of accesses with gaps is not supported. */ + slp_impossible = true; + if (DR_IS_WRITE (data_ref)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "interleaved store with gaps"); + return false; + } + + gaps += diff - 1; + } + + last_accessed_element += diff; + + /* Store the gap from the previous member of the group. If there is no + gap in the access, GROUP_GAP is always 1. */ + GROUP_GAP (vinfo_for_stmt (next)) = diff; + + prev_init = DR_INIT (data_ref); + next = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next)); + /* Count the number of data-refs in the chain. */ + count++; + } + + /* COUNT is the number of accesses found, we multiply it by the size of + the type to get COUNT_IN_BYTES. */ + count_in_bytes = type_size * count; + + /* Check that the size of the interleaving (including gaps) is not + greater than STEP. */ + if (dr_step && dr_step < count_in_bytes + gaps * type_size) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "interleaving size is greater than step for "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, DR_REF (dr)); + } + return false; + } + + /* Check that the size of the interleaving is equal to STEP for stores, + i.e., that there are no gaps. */ + if (dr_step && dr_step != count_in_bytes) + { + if (DR_IS_READ (dr)) + { + slp_impossible = true; + /* There is a gap after the last load in the group. This gap is a + difference between the groupsize and the number of elements. + When there is no gap, this difference should be 0. */ + GROUP_GAP (vinfo_for_stmt (stmt)) = groupsize - count; + } + else + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "interleaved store with gaps"); + return false; + } + } + + /* Check that STEP is a multiple of type size. */ + if (dr_step && (dr_step % type_size) != 0) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "step is not a multiple of type size: step "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, step); + dump_printf (MSG_MISSED_OPTIMIZATION, " size "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, + TYPE_SIZE_UNIT (scalar_type)); + } + return false; + } + + if (groupsize == 0) + groupsize = count; + + GROUP_SIZE (vinfo_for_stmt (stmt)) = groupsize; + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "Detected interleaving of size %d", (int)groupsize); + + /* SLP: create an SLP data structure for every interleaving group of + stores for further analysis in vect_analyse_slp. */ + if (DR_IS_WRITE (dr) && !slp_impossible) + { + if (loop_vinfo) + LOOP_VINFO_GROUPED_STORES (loop_vinfo).safe_push (stmt); + if (bb_vinfo) + BB_VINFO_GROUPED_STORES (bb_vinfo).safe_push (stmt); + } + + /* There is a gap in the end of the group. */ + if (groupsize - last_accessed_element > 0 && loop_vinfo) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Data access with gaps requires scalar " + "epilogue loop"); + if (loop->inner) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "Peeling for outer loop is not supported"); + return false; + } + + LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) = true; + } + } + + return true; +} + + +/* Analyze the access pattern of the data-reference DR. + In case of non-consecutive accesses call vect_analyze_group_access() to + analyze groups of accesses. */ + +static bool +vect_analyze_data_ref_access (struct data_reference *dr) +{ + tree step = DR_STEP (dr); + tree scalar_type = TREE_TYPE (DR_REF (dr)); + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + struct loop *loop = NULL; + + if (loop_vinfo) + loop = LOOP_VINFO_LOOP (loop_vinfo); + + if (loop_vinfo && !step) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "bad data-ref access in loop"); + return false; + } + + /* Allow invariant loads in not nested loops. */ + if (loop_vinfo && integer_zerop (step)) + { + GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = NULL; + if (nested_in_vect_loop_p (loop, stmt)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "zero step in inner loop of nest"); + return false; + } + return DR_IS_READ (dr); + } + + if (loop && nested_in_vect_loop_p (loop, stmt)) + { + /* Interleaved accesses are not yet supported within outer-loop + vectorization for references in the inner-loop. */ + GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = NULL; + + /* For the rest of the analysis we use the outer-loop step. */ + step = STMT_VINFO_DR_STEP (stmt_info); + if (integer_zerop (step)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "zero step in outer loop."); + if (DR_IS_READ (dr)) + return true; + else + return false; + } + } + + /* Consecutive? */ + if (TREE_CODE (step) == INTEGER_CST) + { + HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); + if (!tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)) + || (dr_step < 0 + && !compare_tree_int (TYPE_SIZE_UNIT (scalar_type), -dr_step))) + { + /* Mark that it is not interleaving. */ + GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = NULL; + return true; + } + } + + if (loop && nested_in_vect_loop_p (loop, stmt)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "grouped access in outer loop."); + return false; + } + + /* Assume this is a DR handled by non-constant strided load case. */ + if (TREE_CODE (step) != INTEGER_CST) + return STMT_VINFO_STRIDE_LOAD_P (stmt_info); + + /* Not consecutive access - check if it's a part of interleaving group. */ + return vect_analyze_group_access (dr); +} + + +/* Function vect_analyze_data_ref_accesses. + + Analyze the access pattern of all the data references in the loop. + + FORNOW: the only access pattern that is considered vectorizable is a + simple step 1 (consecutive) access. + + FORNOW: handle only arrays and pointer accesses. */ + +bool +vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo, bb_vec_info bb_vinfo) +{ + unsigned int i; + vec<data_reference_p> datarefs; + struct data_reference *dr; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_analyze_data_ref_accesses ==="); + + if (loop_vinfo) + datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + else + datarefs = BB_VINFO_DATAREFS (bb_vinfo); + + FOR_EACH_VEC_ELT (datarefs, i, dr) + if (STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) + && !vect_analyze_data_ref_access (dr)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: complicated access pattern."); + + if (bb_vinfo) + { + /* Mark the statement as not vectorizable. */ + STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) = false; + continue; + } + else + return false; + } + + return true; +} + +/* Function vect_prune_runtime_alias_test_list. + + Prune a list of ddrs to be tested at run-time by versioning for alias. + Return FALSE if resulting list of ddrs is longer then allowed by + PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS, otherwise return TRUE. */ + +bool +vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo) +{ + vec<ddr_p> ddrs = + LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo); + unsigned i, j; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_prune_runtime_alias_test_list ==="); + + for (i = 0; i < ddrs.length (); ) + { + bool found; + ddr_p ddr_i; + + ddr_i = ddrs[i]; + found = false; + + for (j = 0; j < i; j++) + { + ddr_p ddr_j = ddrs[j]; + + if (vect_vfa_range_equal (ddr_i, ddr_j)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "found equal ranges "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_A (ddr_i))); + dump_printf (MSG_NOTE, ", "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_B (ddr_i))); + dump_printf (MSG_NOTE, " and "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_A (ddr_j))); + dump_printf (MSG_NOTE, ", "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (DDR_B (ddr_j))); + } + found = true; + break; + } + } + + if (found) + { + ddrs.ordered_remove (i); + continue; + } + i++; + } + + if (ddrs.length () > + (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "disable versioning for alias - max number of " + "generated checks exceeded."); + } + + LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo).truncate (0); + + return false; + } + + return true; +} + +/* Check whether a non-affine read in stmt is suitable for gather load + and if so, return a builtin decl for that operation. */ + +tree +vect_check_gather (gimple stmt, loop_vec_info loop_vinfo, tree *basep, + tree *offp, int *scalep) +{ + HOST_WIDE_INT scale = 1, pbitpos, pbitsize; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + tree offtype = NULL_TREE; + tree decl, base, off; + enum machine_mode pmode; + int punsignedp, pvolatilep; + + /* The gather builtins need address of the form + loop_invariant + vector * {1, 2, 4, 8} + or + loop_invariant + sign_extend (vector) * { 1, 2, 4, 8 }. + Unfortunately DR_BASE_ADDRESS/DR_OFFSET can be a mixture + of loop invariants/SSA_NAMEs defined in the loop, with casts, + multiplications and additions in it. To get a vector, we need + a single SSA_NAME that will be defined in the loop and will + contain everything that is not loop invariant and that can be + vectorized. The following code attempts to find such a preexistng + SSA_NAME OFF and put the loop invariants into a tree BASE + that can be gimplified before the loop. */ + base = get_inner_reference (DR_REF (dr), &pbitsize, &pbitpos, &off, + &pmode, &punsignedp, &pvolatilep, false); + gcc_assert (base != NULL_TREE && (pbitpos % BITS_PER_UNIT) == 0); + + if (TREE_CODE (base) == MEM_REF) + { + if (!integer_zerop (TREE_OPERAND (base, 1))) + { + if (off == NULL_TREE) + { + double_int moff = mem_ref_offset (base); + off = double_int_to_tree (sizetype, moff); + } + else + off = size_binop (PLUS_EXPR, off, + fold_convert (sizetype, TREE_OPERAND (base, 1))); + } + base = TREE_OPERAND (base, 0); + } + else + base = build_fold_addr_expr (base); + + if (off == NULL_TREE) + off = size_zero_node; + + /* If base is not loop invariant, either off is 0, then we start with just + the constant offset in the loop invariant BASE and continue with base + as OFF, otherwise give up. + We could handle that case by gimplifying the addition of base + off + into some SSA_NAME and use that as off, but for now punt. */ + if (!expr_invariant_in_loop_p (loop, base)) + { + if (!integer_zerop (off)) + return NULL_TREE; + off = base; + base = size_int (pbitpos / BITS_PER_UNIT); + } + /* Otherwise put base + constant offset into the loop invariant BASE + and continue with OFF. */ + else + { + base = fold_convert (sizetype, base); + base = size_binop (PLUS_EXPR, base, size_int (pbitpos / BITS_PER_UNIT)); + } + + /* OFF at this point may be either a SSA_NAME or some tree expression + from get_inner_reference. Try to peel off loop invariants from it + into BASE as long as possible. */ + STRIP_NOPS (off); + while (offtype == NULL_TREE) + { + enum tree_code code; + tree op0, op1, add = NULL_TREE; + + if (TREE_CODE (off) == SSA_NAME) + { + gimple def_stmt = SSA_NAME_DEF_STMT (off); + + if (expr_invariant_in_loop_p (loop, off)) + return NULL_TREE; + + if (gimple_code (def_stmt) != GIMPLE_ASSIGN) + break; + + op0 = gimple_assign_rhs1 (def_stmt); + code = gimple_assign_rhs_code (def_stmt); + op1 = gimple_assign_rhs2 (def_stmt); + } + else + { + if (get_gimple_rhs_class (TREE_CODE (off)) == GIMPLE_TERNARY_RHS) + return NULL_TREE; + code = TREE_CODE (off); + extract_ops_from_tree (off, &code, &op0, &op1); + } + switch (code) + { + case POINTER_PLUS_EXPR: + case PLUS_EXPR: + if (expr_invariant_in_loop_p (loop, op0)) + { + add = op0; + off = op1; + do_add: + add = fold_convert (sizetype, add); + if (scale != 1) + add = size_binop (MULT_EXPR, add, size_int (scale)); + base = size_binop (PLUS_EXPR, base, add); + continue; + } + if (expr_invariant_in_loop_p (loop, op1)) + { + add = op1; + off = op0; + goto do_add; + } + break; + case MINUS_EXPR: + if (expr_invariant_in_loop_p (loop, op1)) + { + add = fold_convert (sizetype, op1); + add = size_binop (MINUS_EXPR, size_zero_node, add); + off = op0; + goto do_add; + } + break; + case MULT_EXPR: + if (scale == 1 && host_integerp (op1, 0)) + { + scale = tree_low_cst (op1, 0); + off = op0; + continue; + } + break; + case SSA_NAME: + off = op0; + continue; + CASE_CONVERT: + if (!POINTER_TYPE_P (TREE_TYPE (op0)) + && !INTEGRAL_TYPE_P (TREE_TYPE (op0))) + break; + if (TYPE_PRECISION (TREE_TYPE (op0)) + == TYPE_PRECISION (TREE_TYPE (off))) + { + off = op0; + continue; + } + if (TYPE_PRECISION (TREE_TYPE (op0)) + < TYPE_PRECISION (TREE_TYPE (off))) + { + off = op0; + offtype = TREE_TYPE (off); + STRIP_NOPS (off); + continue; + } + break; + default: + break; + } + break; + } + + /* If at the end OFF still isn't a SSA_NAME or isn't + defined in the loop, punt. */ + if (TREE_CODE (off) != SSA_NAME + || expr_invariant_in_loop_p (loop, off)) + return NULL_TREE; + + if (offtype == NULL_TREE) + offtype = TREE_TYPE (off); + + decl = targetm.vectorize.builtin_gather (STMT_VINFO_VECTYPE (stmt_info), + offtype, scale); + if (decl == NULL_TREE) + return NULL_TREE; + + if (basep) + *basep = base; + if (offp) + *offp = off; + if (scalep) + *scalep = scale; + return decl; +} + +/* Check wether a non-affine load in STMT (being in the loop referred to + in LOOP_VINFO) is suitable for handling as strided load. That is the case + if its address is a simple induction variable. If so return the base + of that induction variable in *BASEP and the (loop-invariant) step + in *STEPP, both only when that pointer is non-zero. + + This handles ARRAY_REFs (with variant index) and MEM_REFs (with variant + base pointer) only. */ + +static bool +vect_check_strided_load (gimple stmt, loop_vec_info loop_vinfo) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + tree base, off; + affine_iv iv; + + if (!DR_IS_READ (dr)) + return false; + + base = DR_REF (dr); + + if (TREE_CODE (base) == ARRAY_REF) + { + off = TREE_OPERAND (base, 1); + base = TREE_OPERAND (base, 0); + } + else if (TREE_CODE (base) == MEM_REF) + { + off = TREE_OPERAND (base, 0); + base = TREE_OPERAND (base, 1); + } + else + return false; + + if (TREE_CODE (off) != SSA_NAME) + return false; + + if (!expr_invariant_in_loop_p (loop, base) + || !simple_iv (loop, loop_containing_stmt (stmt), off, &iv, true)) + return false; + + return true; +} + +/* Function vect_analyze_data_refs. + + Find all the data references in the loop or basic block. + + The general structure of the analysis of data refs in the vectorizer is as + follows: + 1- vect_analyze_data_refs(loop/bb): call + compute_data_dependences_for_loop/bb to find and analyze all data-refs + in the loop/bb and their dependences. + 2- vect_analyze_dependences(): apply dependence testing using ddrs. + 3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok. + 4- vect_analyze_drs_access(): check that ref_stmt.step is ok. + +*/ + +bool +vect_analyze_data_refs (loop_vec_info loop_vinfo, + bb_vec_info bb_vinfo, + int *min_vf) +{ + struct loop *loop = NULL; + basic_block bb = NULL; + unsigned int i; + vec<data_reference_p> datarefs; + struct data_reference *dr; + tree scalar_type; + bool res, stop_bb_analysis = false; + + if (dump_enabled_p ()) + dump_printf_loc (MSG_NOTE, vect_location, + "=== vect_analyze_data_refs ===\n"); + + if (loop_vinfo) + { + loop = LOOP_VINFO_LOOP (loop_vinfo); + res = compute_data_dependences_for_loop + (loop, true, + &LOOP_VINFO_LOOP_NEST (loop_vinfo), + &LOOP_VINFO_DATAREFS (loop_vinfo), + &LOOP_VINFO_DDRS (loop_vinfo)); + + if (!res) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: loop contains function calls" + " or data references that cannot be analyzed"); + return false; + } + + datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + } + else + { + gimple_stmt_iterator gsi; + + bb = BB_VINFO_BB (bb_vinfo); + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + if (!find_data_references_in_stmt (NULL, stmt, + &BB_VINFO_DATAREFS (bb_vinfo))) + { + /* Mark the rest of the basic-block as unvectorizable. */ + for (; !gsi_end_p (gsi); gsi_next (&gsi)) + { + stmt = gsi_stmt (gsi); + STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (stmt)) = false; + } + break; + } + } + if (!compute_all_dependences (BB_VINFO_DATAREFS (bb_vinfo), + &BB_VINFO_DDRS (bb_vinfo), + vNULL, true)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: basic block contains function" + " calls or data references that cannot be" + " analyzed"); + return false; + } + + datarefs = BB_VINFO_DATAREFS (bb_vinfo); + } + + /* Go through the data-refs, check that the analysis succeeded. Update + pointer from stmt_vec_info struct to DR and vectype. */ + + FOR_EACH_VEC_ELT (datarefs, i, dr) + { + gimple stmt; + stmt_vec_info stmt_info; + tree base, offset, init; + bool gather = false; + int vf; + + if (!dr || !DR_REF (dr)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: unhandled data-ref "); + return false; + } + + stmt = DR_STMT (dr); + stmt_info = vinfo_for_stmt (stmt); + + if (stop_bb_analysis) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + continue; + } + + /* Check that analysis of the data-ref succeeded. */ + if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr) + || !DR_STEP (dr)) + { + /* If target supports vector gather loads, see if they can't + be used. */ + if (loop_vinfo + && DR_IS_READ (dr) + && !TREE_THIS_VOLATILE (DR_REF (dr)) + && targetm.vectorize.builtin_gather != NULL + && !nested_in_vect_loop_p (loop, stmt)) + { + struct data_reference *newdr + = create_data_ref (NULL, loop_containing_stmt (stmt), + DR_REF (dr), stmt, true); + gcc_assert (newdr != NULL && DR_REF (newdr)); + if (DR_BASE_ADDRESS (newdr) + && DR_OFFSET (newdr) + && DR_INIT (newdr) + && DR_STEP (newdr) + && integer_zerop (DR_STEP (newdr))) + { + dr = newdr; + gather = true; + } + else + free_data_ref (newdr); + } + + if (!gather) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: data ref analysis " + "failed "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + return false; + } + } + + if (TREE_CODE (DR_BASE_ADDRESS (dr)) == INTEGER_CST) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: base addr of dr is a " + "constant"); + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + free_data_ref (dr); + return false; + } + + if (TREE_THIS_VOLATILE (DR_REF (dr))) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: volatile type "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + return false; + } + + if (stmt_can_throw_internal (stmt)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: statement can throw an " + "exception "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + free_data_ref (dr); + return false; + } + + if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF + && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1))) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: statement is bitfield " + "access "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + free_data_ref (dr); + return false; + } + + base = unshare_expr (DR_BASE_ADDRESS (dr)); + offset = unshare_expr (DR_OFFSET (dr)); + init = unshare_expr (DR_INIT (dr)); + + if (is_gimple_call (stmt)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: dr in a call "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + free_data_ref (dr); + return false; + } + + /* Update DR field in stmt_vec_info struct. */ + + /* If the dataref is in an inner-loop of the loop that is considered for + for vectorization, we also want to analyze the access relative to + the outer-loop (DR contains information only relative to the + inner-most enclosing loop). We do that by building a reference to the + first location accessed by the inner-loop, and analyze it relative to + the outer-loop. */ + if (loop && nested_in_vect_loop_p (loop, stmt)) + { + tree outer_step, outer_base, outer_init; + HOST_WIDE_INT pbitsize, pbitpos; + tree poffset; + enum machine_mode pmode; + int punsignedp, pvolatilep; + affine_iv base_iv, offset_iv; + tree dinit; + + /* Build a reference to the first location accessed by the + inner-loop: *(BASE+INIT). (The first location is actually + BASE+INIT+OFFSET, but we add OFFSET separately later). */ + tree inner_base = build_fold_indirect_ref + (fold_build_pointer_plus (base, init)); + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "analyze in outer-loop: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, inner_base); + } + + outer_base = get_inner_reference (inner_base, &pbitsize, &pbitpos, + &poffset, &pmode, &punsignedp, &pvolatilep, false); + gcc_assert (outer_base != NULL_TREE); + + if (pbitpos % BITS_PER_UNIT != 0) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "failed: bit offset alignment.\n"); + return false; + } + + outer_base = build_fold_addr_expr (outer_base); + if (!simple_iv (loop, loop_containing_stmt (stmt), outer_base, + &base_iv, false)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "failed: evolution of base is not affine.\n"); + return false; + } + + if (offset) + { + if (poffset) + poffset = fold_build2 (PLUS_EXPR, TREE_TYPE (offset), offset, + poffset); + else + poffset = offset; + } + + if (!poffset) + { + offset_iv.base = ssize_int (0); + offset_iv.step = ssize_int (0); + } + else if (!simple_iv (loop, loop_containing_stmt (stmt), poffset, + &offset_iv, false)) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "evolution of offset is not affine.\n"); + return false; + } + + outer_init = ssize_int (pbitpos / BITS_PER_UNIT); + split_constant_offset (base_iv.base, &base_iv.base, &dinit); + outer_init = size_binop (PLUS_EXPR, outer_init, dinit); + split_constant_offset (offset_iv.base, &offset_iv.base, &dinit); + outer_init = size_binop (PLUS_EXPR, outer_init, dinit); + + outer_step = size_binop (PLUS_EXPR, + fold_convert (ssizetype, base_iv.step), + fold_convert (ssizetype, offset_iv.step)); + + STMT_VINFO_DR_STEP (stmt_info) = outer_step; + /* FIXME: Use canonicalize_base_object_address (base_iv.base); */ + STMT_VINFO_DR_BASE_ADDRESS (stmt_info) = base_iv.base; + STMT_VINFO_DR_INIT (stmt_info) = outer_init; + STMT_VINFO_DR_OFFSET (stmt_info) = + fold_convert (ssizetype, offset_iv.base); + STMT_VINFO_DR_ALIGNED_TO (stmt_info) = + size_int (highest_pow2_factor (offset_iv.base)); + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, + "\touter base_address: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, + STMT_VINFO_DR_BASE_ADDRESS (stmt_info)); + dump_printf (MSG_NOTE, "\n\touter offset from base address: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, + STMT_VINFO_DR_OFFSET (stmt_info)); + dump_printf (MSG_NOTE, + "\n\touter constant offset from base address: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, + STMT_VINFO_DR_INIT (stmt_info)); + dump_printf (MSG_NOTE, "\n\touter step: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, + STMT_VINFO_DR_STEP (stmt_info)); + dump_printf (MSG_NOTE, "\n\touter aligned to: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, + STMT_VINFO_DR_ALIGNED_TO (stmt_info)); + } + } + + if (STMT_VINFO_DATA_REF (stmt_info)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: more than one data ref " + "in stmt: "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + + if (bb_vinfo) + { + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + free_data_ref (dr); + return false; + } + + STMT_VINFO_DATA_REF (stmt_info) = dr; + + /* Set vectype for STMT. */ + scalar_type = TREE_TYPE (DR_REF (dr)); + STMT_VINFO_VECTYPE (stmt_info) = + get_vectype_for_scalar_type (scalar_type); + if (!STMT_VINFO_VECTYPE (stmt_info)) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: no vectype for stmt: "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + dump_printf (MSG_MISSED_OPTIMIZATION, " scalar_type: "); + dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_DETAILS, + scalar_type); + } + + if (bb_vinfo) + { + /* Mark the statement as not vectorizable. */ + STMT_VINFO_VECTORIZABLE (stmt_info) = false; + stop_bb_analysis = true; + continue; + } + + if (gather) + { + STMT_VINFO_DATA_REF (stmt_info) = NULL; + free_data_ref (dr); + } + return false; + } + + /* Adjust the minimal vectorization factor according to the + vector type. */ + vf = TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info)); + if (vf > *min_vf) + *min_vf = vf; + + if (gather) + { + unsigned int j, k, n; + struct data_reference *olddr + = datarefs[i]; + vec<ddr_p> ddrs = LOOP_VINFO_DDRS (loop_vinfo); + struct data_dependence_relation *ddr, *newddr; + bool bad = false; + tree off; + vec<loop_p> nest = LOOP_VINFO_LOOP_NEST (loop_vinfo); + + gather = 0 != vect_check_gather (stmt, loop_vinfo, NULL, &off, NULL); + if (gather + && get_vectype_for_scalar_type (TREE_TYPE (off)) == NULL_TREE) + gather = false; + if (!gather) + { + STMT_VINFO_DATA_REF (stmt_info) = NULL; + free_data_ref (dr); + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: not suitable for gather " + "load "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + return false; + } + + n = datarefs.length () - 1; + for (j = 0, k = i - 1; j < i; j++) + { + ddr = ddrs[k]; + gcc_assert (DDR_B (ddr) == olddr); + newddr = initialize_data_dependence_relation (DDR_A (ddr), dr, + nest); + ddrs[k] = newddr; + free_dependence_relation (ddr); + if (!bad + && DR_IS_WRITE (DDR_A (newddr)) + && DDR_ARE_DEPENDENT (newddr) != chrec_known) + bad = true; + k += --n; + } + + k++; + n = k + datarefs.length () - i - 1; + for (; k < n; k++) + { + ddr = ddrs[k]; + gcc_assert (DDR_A (ddr) == olddr); + newddr = initialize_data_dependence_relation (dr, DDR_B (ddr), + nest); + ddrs[k] = newddr; + free_dependence_relation (ddr); + if (!bad + && DR_IS_WRITE (DDR_B (newddr)) + && DDR_ARE_DEPENDENT (newddr) != chrec_known) + bad = true; + } + + k = ddrs.length () + - datarefs.length () + i; + ddr = ddrs[k]; + gcc_assert (DDR_A (ddr) == olddr && DDR_B (ddr) == olddr); + newddr = initialize_data_dependence_relation (dr, dr, nest); + ddrs[k] = newddr; + free_dependence_relation (ddr); + datarefs[i] = dr; + + if (bad) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: data dependence conflict" + " prevents gather load"); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + return false; + } + + STMT_VINFO_GATHER_P (stmt_info) = true; + } + else if (loop_vinfo + && TREE_CODE (DR_STEP (dr)) != INTEGER_CST) + { + bool strided_load = false; + if (!nested_in_vect_loop_p (loop, stmt)) + strided_load = vect_check_strided_load (stmt, loop_vinfo); + if (!strided_load) + { + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "not vectorized: not suitable for strided " + "load "); + dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); + } + return false; + } + STMT_VINFO_STRIDE_LOAD_P (stmt_info) = true; + } + } + + return true; +} + + +/* Function vect_get_new_vect_var. + + Returns a name for a new variable. The current naming scheme appends the + prefix "vect_" or "vect_p" (depending on the value of VAR_KIND) to + the name of vectorizer generated variables, and appends that to NAME if + provided. */ + +tree +vect_get_new_vect_var (tree type, enum vect_var_kind var_kind, const char *name) +{ + const char *prefix; + tree new_vect_var; + + switch (var_kind) + { + case vect_simple_var: + prefix = "vect_"; + break; + case vect_scalar_var: + prefix = "stmp_"; + break; + case vect_pointer_var: + prefix = "vect_p"; + break; + default: + gcc_unreachable (); + } + + if (name) + { + char* tmp = concat (prefix, name, NULL); + new_vect_var = create_tmp_reg (type, tmp); + free (tmp); + } + else + new_vect_var = create_tmp_reg (type, prefix); + + return new_vect_var; +} + + +/* Function vect_create_addr_base_for_vector_ref. + + Create an expression that computes the address of the first memory location + that will be accessed for a data reference. + + Input: + STMT: The statement containing the data reference. + NEW_STMT_LIST: Must be initialized to NULL_TREE or a statement list. + OFFSET: Optional. If supplied, it is be added to the initial address. + LOOP: Specify relative to which loop-nest should the address be computed. + For example, when the dataref is in an inner-loop nested in an + outer-loop that is now being vectorized, LOOP can be either the + outer-loop, or the inner-loop. The first memory location accessed + by the following dataref ('in' points to short): + + for (i=0; i<N; i++) + for (j=0; j<M; j++) + s += in[i+j] + + is as follows: + if LOOP=i_loop: &in (relative to i_loop) + if LOOP=j_loop: &in+i*2B (relative to j_loop) + + Output: + 1. Return an SSA_NAME whose value is the address of the memory location of + the first vector of the data reference. + 2. If new_stmt_list is not NULL_TREE after return then the caller must insert + these statement(s) which define the returned SSA_NAME. + + FORNOW: We are only handling array accesses with step 1. */ + +tree +vect_create_addr_base_for_vector_ref (gimple stmt, + gimple_seq *new_stmt_list, + tree offset, + struct loop *loop) +{ + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + tree data_ref_base = unshare_expr (DR_BASE_ADDRESS (dr)); + const char *base_name; + tree data_ref_base_var; + tree vec_stmt; + tree addr_base, addr_expr; + tree dest; + gimple_seq seq = NULL; + tree base_offset = unshare_expr (DR_OFFSET (dr)); + tree init = unshare_expr (DR_INIT (dr)); + tree vect_ptr_type; + tree step = TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + tree base; + + if (loop_vinfo && loop && loop != (gimple_bb (stmt))->loop_father) + { + struct loop *outer_loop = LOOP_VINFO_LOOP (loop_vinfo); + + gcc_assert (nested_in_vect_loop_p (outer_loop, stmt)); + + data_ref_base = unshare_expr (STMT_VINFO_DR_BASE_ADDRESS (stmt_info)); + base_offset = unshare_expr (STMT_VINFO_DR_OFFSET (stmt_info)); + init = unshare_expr (STMT_VINFO_DR_INIT (stmt_info)); + } + + if (loop_vinfo) + base_name = get_name (data_ref_base); + else + { + base_offset = ssize_int (0); + init = ssize_int (0); + base_name = get_name (DR_REF (dr)); + } + + data_ref_base_var = create_tmp_var (TREE_TYPE (data_ref_base), "batmp"); + data_ref_base = force_gimple_operand (data_ref_base, &seq, true, + data_ref_base_var); + gimple_seq_add_seq (new_stmt_list, seq); + + /* Create base_offset */ + base_offset = size_binop (PLUS_EXPR, + fold_convert (sizetype, base_offset), + fold_convert (sizetype, init)); + dest = create_tmp_var (sizetype, "base_off"); + base_offset = force_gimple_operand (base_offset, &seq, true, dest); + gimple_seq_add_seq (new_stmt_list, seq); + + if (offset) + { + tree tmp = create_tmp_var (sizetype, "offset"); + + offset = fold_build2 (MULT_EXPR, sizetype, + fold_convert (sizetype, offset), step); + base_offset = fold_build2 (PLUS_EXPR, sizetype, + base_offset, offset); + base_offset = force_gimple_operand (base_offset, &seq, false, tmp); + gimple_seq_add_seq (new_stmt_list, seq); + } + + /* base + base_offset */ + if (loop_vinfo) + addr_base = fold_build_pointer_plus (data_ref_base, base_offset); + else + { + addr_base = build1 (ADDR_EXPR, + build_pointer_type (TREE_TYPE (DR_REF (dr))), + unshare_expr (DR_REF (dr))); + } + + vect_ptr_type = build_pointer_type (STMT_VINFO_VECTYPE (stmt_info)); + base = get_base_address (DR_REF (dr)); + if (base + && TREE_CODE (base) == MEM_REF) + vect_ptr_type + = build_qualified_type (vect_ptr_type, + TYPE_QUALS (TREE_TYPE (TREE_OPERAND (base, 0)))); + + vec_stmt = fold_convert (vect_ptr_type, addr_base); + addr_expr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, + base_name); + vec_stmt = force_gimple_operand (vec_stmt, &seq, false, addr_expr); + gimple_seq_add_seq (new_stmt_list, seq); + + if (DR_PTR_INFO (dr) + && TREE_CODE (vec_stmt) == SSA_NAME) + { + duplicate_ssa_name_ptr_info (vec_stmt, DR_PTR_INFO (dr)); + if (offset) + mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (vec_stmt)); + } + + if (dump_enabled_p ()) + { + dump_printf_loc (MSG_NOTE, vect_location, "created "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, vec_stmt); + } + + return vec_stmt; +} + + +/* Function vect_create_data_ref_ptr. + + Create a new pointer-to-AGGR_TYPE variable (ap), that points to the first + location accessed in the loop by STMT, along with the def-use update + chain to appropriately advance the pointer through the loop iterations. + Also set aliasing information for the pointer. This pointer is used by + the callers to this function to create a memory reference expression for + vector load/store access. + + Input: + 1. STMT: a stmt that references memory. Expected to be of the form + GIMPLE_ASSIGN <name, data-ref> or + GIMPLE_ASSIGN <data-ref, name>. + 2. AGGR_TYPE: the type of the reference, which should be either a vector + or an array. + 3. AT_LOOP: the loop where the vector memref is to be created. + 4. OFFSET (optional): an offset to be added to the initial address accessed + by the data-ref in STMT. + 5. BSI: location where the new stmts are to be placed if there is no loop + 6. ONLY_INIT: indicate if ap is to be updated in the loop, or remain + pointing to the initial address. + + Output: + 1. Declare a new ptr to vector_type, and have it point to the base of the + data reference (initial addressed accessed by the data reference). + For example, for vector of type V8HI, the following code is generated: + + v8hi *ap; + ap = (v8hi *)initial_address; + + if OFFSET is not supplied: + initial_address = &a[init]; + if OFFSET is supplied: + initial_address = &a[init + OFFSET]; + + Return the initial_address in INITIAL_ADDRESS. + + 2. If ONLY_INIT is true, just return the initial pointer. Otherwise, also + update the pointer in each iteration of the loop. + + Return the increment stmt that updates the pointer in PTR_INCR. + + 3. Set INV_P to true if the access pattern of the data reference in the + vectorized loop is invariant. Set it to false otherwise. + + 4. Return the pointer. */ + +tree +vect_create_data_ref_ptr (gimple stmt, tree aggr_type, struct loop *at_loop, + tree offset, tree *initial_address, + gimple_stmt_iterator *gsi, gimple *ptr_incr, + bool only_init, bool *inv_p) +{ + const char *base_name; + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + struct loop *loop = NULL; + bool nested_in_vect_loop = false; + struct loop *containing_loop = NULL; + tree aggr_ptr_type; + tree aggr_ptr; + tree new_temp; + gimple vec_stmt; + gimple_seq new_stmt_list = NULL; + edge pe = NULL; + basic_block new_bb; + tree aggr_ptr_init; + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + tree aptr; + gimple_stmt_iterator incr_gsi; + bool insert_after; + bool negative; + tree indx_before_incr, indx_after_incr; + gimple incr; + tree step; + bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info); + tree base; + + gcc_assert (TREE_CODE (aggr_type) == ARRAY_TYPE + || TREE_CODE (aggr_type) == VECTOR_TYPE); + + if (loop_vinfo) + { + loop = LOOP_VINFO_LOOP (loop_vinfo); + nested_in_vect_loop = nested_in_vect_loop_p (loop, stmt); + containing_loop = (gimple_bb (stmt))->loop_father; + pe = loop_preheader_edge (loop); + } + else + { + gcc_assert (bb_vinfo); + only_init = true; + *ptr_incr = NULL; + } + + /* Check the step (evolution) of the load in LOOP, and record + whether it's invariant. */ + if (nested_in_vect_loop) + step = STMT_VINFO_DR_STEP (stmt_info); + else + step = DR_STEP (STMT_VINFO_DATA_REF (stmt_info)); + + if (tree_int_cst_compare (step, size_zero_node) == 0) + *inv_p = true; + else + *inv_p = false; + negative = tree_int_cst_compare (step, size_zero_node) < 0; + + /* Create an expression for the first address accessed by this load + in LOOP. */ + base_name = get_name (DR_BASE_ADDRESS (dr)); + + if (dump_enabled_p ()) + { + tree dr_base_type = TREE_TYPE (DR_BASE_OBJECT (dr)); + dump_printf_loc (MSG_NOTE, vect_location, + "create %s-pointer variable to type: ", + tree_code_name[(int) TREE_CODE (aggr_type)]); + dump_generic_expr (MSG_NOTE, TDF_SLIM, aggr_type); + if (TREE_CODE (dr_base_type) == ARRAY_TYPE) + dump_printf (MSG_NOTE, " vectorizing an array ref: "); + else if (TREE_CODE (dr_base_type) == RECORD_TYPE) + dump_printf (MSG_NOTE, " vectorizing a record based array ref: "); + else + dump_printf (MSG_NOTE, " vectorizing a pointer ref: "); + dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_BASE_OBJECT (dr)); + } + + /* (1) Create the new aggregate-pointer variable. */ + aggr_ptr_type = build_pointer_type (aggr_type); + base = get_base_address (DR_REF (dr)); + if (base + && TREE_CODE (base) == MEM_REF) + aggr_ptr_type + = build_qualified_type (aggr_ptr_type, + TYPE_QUALS (TREE_TYPE (TREE_OPERAND (base, 0)))); + aggr_ptr = vect_get_new_vect_var (aggr_ptr_type, vect_pointer_var, base_name); + + /* Vector and array types inherit the alias set of their component + type by default so we need to use a ref-all pointer if the data + reference does not conflict with the created aggregated data + reference because it is not addressable. */ + if (!alias_sets_conflict_p (get_deref_alias_set (aggr_ptr), + get_alias_set (DR_REF (dr)))) + { + aggr_ptr_type + = build_pointer_type_for_mode (aggr_type, + TYPE_MODE (aggr_ptr_type), true); + aggr_ptr = vect_get_new_vect_var (aggr_ptr_type, vect_pointer_var, + base_name); + } + + /* Likewise for any of the data references in the stmt group. */ + else if (STMT_VINFO_GROUP_SIZE (stmt_info) > 1) + { + gimple orig_stmt = STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_info); + do + { + tree lhs = gimple_assign_lhs (orig_stmt); + if (!alias_sets_conflict_p (get_deref_alias_set (aggr_ptr), + get_alias_set (lhs))) + { + aggr_ptr_type + = build_pointer_type_for_mode (aggr_type, + TYPE_MODE (aggr_ptr_type), true); + aggr_ptr + = vect_get_new_vect_var (aggr_ptr_type, vect_pointer_var, + base_name); + break; + } + + orig_stmt = STMT_VINFO_GROUP_NEXT_ELEMENT (vinfo_for_stmt (orig_stmt)); + } + while (orig_stmt); + } + + /* Note: If the dataref is in an inner-loop nested in LOOP, and we are + vectorizing LOOP (i.e., outer-loop vectorization), we need to create two + def-use update cycles for the pointer: one relative to the outer-loop + (LOOP), which is what steps (3) and (4) below do. The other is relative + to the inner-loop (which is the inner-most loop containing the dataref), + and this is done be step (5) below. + + When vectorizing inner-most loops, the vectorized loop (LOOP) is also the + inner-most loop, and so steps (3),(4) work the same, and step (5) is + redundant. Steps (3),(4) create the following: + + vp0 = &base_addr; + LOOP: vp1 = phi(vp0,vp2) + ... + ... + vp2 = vp1 + step + goto LOOP + + If there is an inner-loop nested in loop, then step (5) will also be + applied, and an additional update in the inner-loop will be created: + + vp0 = &base_addr; + LOOP: vp1 = phi(vp0,vp2) + ... + inner: vp3 = phi(vp1,vp4) + vp4 = vp3 + inner_step + if () goto inner + ... + vp2 = vp1 + step + if () goto LOOP */ + + /* (2) Calculate the initial address of the aggregate-pointer, and set + the aggregate-pointer to point to it before the loop. */ + + /* Create: (&(base[init_val+offset]) in the loop preheader. */ + + new_temp = vect_create_addr_base_for_vector_ref (stmt, &new_stmt_list, + offset, loop); + if (new_stmt_list) + { + if (pe) + { + new_bb = gsi_insert_seq_on_edge_immediate (pe, new_stmt_list); + gcc_assert (!new_bb); + } + else + gsi_insert_seq_before (gsi, new_stmt_list, GSI_SAME_STMT); + } + + *initial_address = new_temp; + + /* Create: p = (aggr_type *) initial_base */ + if (TREE_CODE (new_temp) != SSA_NAME + || !useless_type_conversion_p (aggr_ptr_type, TREE_TYPE (new_temp))) + { + vec_stmt = gimple_build_assign (aggr_ptr, + fold_convert (aggr_ptr_type, new_temp)); + aggr_ptr_init = make_ssa_name (aggr_ptr, vec_stmt); + /* Copy the points-to information if it exists. */ + if (DR_PTR_INFO (dr)) + duplicate_ssa_name_ptr_info (aggr_ptr_init, DR_PTR_INFO (dr)); + gimple_assign_set_lhs (vec_stmt, aggr_ptr_init); + if (pe) + { + new_bb = gsi_insert_on_edge_immediate (pe, vec_stmt); + gcc_assert (!new_bb); + } + else + gsi_insert_before (gsi, vec_stmt, GSI_SAME_STMT); + } + else + aggr_ptr_init = new_temp; + + /* (3) Handle the updating of the aggregate-pointer inside the loop. + This is needed when ONLY_INIT is false, and also when AT_LOOP is the + inner-loop nested in LOOP (during outer-loop vectorization). */ + + /* No update in loop is required. */ + if (only_init && (!loop_vinfo || at_loop == loop)) + aptr = aggr_ptr_init; + else + { + /* The step of the aggregate pointer is the type size. */ + tree step = TYPE_SIZE_UNIT (aggr_type); + /* One exception to the above is when the scalar step of the load in + LOOP is zero. In this case the step here is also zero. */ + if (*inv_p) + step = size_zero_node; + else if (negative) + step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step); + + standard_iv_increment_position (loop, &incr_gsi, &insert_after); + + create_iv (aggr_ptr_init, + fold_convert (aggr_ptr_type, step), + aggr_ptr, loop, &incr_gsi, insert_after, + &indx_before_incr, &indx_after_incr); + incr = gsi_stmt (incr_gsi); + set_vinfo_for_stmt (incr, new_stmt_vec_info (incr, loop_vinfo, NULL)); + + /* Copy the points-to information if it exists. */ + if (DR_PTR_INFO (dr)) + { + duplicate_ssa_name_ptr_info (indx_before_incr, DR_PTR_INFO (dr)); + duplicate_ssa_name_ptr_info (indx_after_incr, DR_PTR_INFO (dr)); + } + if (ptr_incr) + *ptr_incr = incr; + + aptr = indx_before_incr; + } + + if (!nested_in_vect_loop || only_init) + return aptr; + + + /* (4) Handle the updating of the aggregate-pointer inside the inner-loop + nested in LOOP, if exists. */ + + gcc_assert (nested_in_vect_loop); + if (!only_init) + { + standard_iv_increment_position (containing_loop, &incr_gsi, + &insert_after); + create_iv (aptr, fold_convert (aggr_ptr_type, DR_STEP (dr)), aggr_ptr, + containing_loop, &incr_gsi, insert_after, &indx_before_incr, + &indx_after_incr); + incr = gsi_stmt (incr_gsi); + set_vinfo_for_stmt (incr, new_stmt_vec_info (incr, loop_vinfo, NULL)); + + /* Copy the points-to information if it exists. */ + if (DR_PTR_INFO (dr)) + { + duplicate_ssa_name_ptr_info (indx_before_incr, DR_PTR_INFO (dr)); + duplicate_ssa_name_ptr_info (indx_after_incr, DR_PTR_INFO (dr)); + } + if (ptr_incr) + *ptr_incr = incr; + + return indx_before_incr; + } + else + gcc_unreachable (); +} + + +/* Function bump_vector_ptr + + Increment a pointer (to a vector type) by vector-size. If requested, + i.e. if PTR-INCR is given, then also connect the new increment stmt + to the existing def-use update-chain of the pointer, by modifying + the PTR_INCR as illustrated below: + + The pointer def-use update-chain before this function: + DATAREF_PTR = phi (p_0, p_2) + .... + PTR_INCR: p_2 = DATAREF_PTR + step + + The pointer def-use update-chain after this function: + DATAREF_PTR = phi (p_0, p_2) + .... + NEW_DATAREF_PTR = DATAREF_PTR + BUMP + .... + PTR_INCR: p_2 = NEW_DATAREF_PTR + step + + Input: + DATAREF_PTR - ssa_name of a pointer (to vector type) that is being updated + in the loop. + PTR_INCR - optional. The stmt that updates the pointer in each iteration of + the loop. The increment amount across iterations is expected + to be vector_size. + BSI - location where the new update stmt is to be placed. + STMT - the original scalar memory-access stmt that is being vectorized. + BUMP - optional. The offset by which to bump the pointer. If not given, + the offset is assumed to be vector_size. + + Output: Return NEW_DATAREF_PTR as illustrated above. + +*/ + +tree +bump_vector_ptr (tree dataref_ptr, gimple ptr_incr, gimple_stmt_iterator *gsi, + gimple stmt, tree bump) +{ + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + tree update = TYPE_SIZE_UNIT (vectype); + gimple incr_stmt; + ssa_op_iter iter; + use_operand_p use_p; + tree new_dataref_ptr; + + if (bump) + update = bump; + + new_dataref_ptr = copy_ssa_name (dataref_ptr, NULL); + incr_stmt = gimple_build_assign_with_ops (POINTER_PLUS_EXPR, new_dataref_ptr, + dataref_ptr, update); + vect_finish_stmt_generation (stmt, incr_stmt, gsi); + + /* Copy the points-to information if it exists. */ + if (DR_PTR_INFO (dr)) + { + duplicate_ssa_name_ptr_info (new_dataref_ptr, DR_PTR_INFO (dr)); + mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (new_dataref_ptr)); + } + + if (!ptr_incr) + return new_dataref_ptr; + + /* Update the vector-pointer's cross-iteration increment. */ + FOR_EACH_SSA_USE_OPERAND (use_p, ptr_incr, iter, SSA_OP_USE) + { + tree use = USE_FROM_PTR (use_p); + + if (use == dataref_ptr) + SET_USE (use_p, new_dataref_ptr); + else + gcc_assert (tree_int_cst_compare (use, update) == 0); + } + + return new_dataref_ptr; +} + + +/* Function vect_create_destination_var. + + Create a new temporary of type VECTYPE. */ + +tree +vect_create_destination_var (tree scalar_dest, tree vectype) +{ + tree vec_dest; + const char *new_name; + tree type; + enum vect_var_kind kind; + + kind = vectype ? vect_simple_var : vect_scalar_var; + type = vectype ? vectype : TREE_TYPE (scalar_dest); + + gcc_assert (TREE_CODE (scalar_dest) == SSA_NAME); + + new_name = get_name (scalar_dest); + if (!new_name) + new_name = "var_"; + vec_dest = vect_get_new_vect_var (type, kind, new_name); + + return vec_dest; +} + +/* Function vect_grouped_store_supported. + + Returns TRUE if interleave high and interleave low permutations + are supported, and FALSE otherwise. */ + +bool +vect_grouped_store_supported (tree vectype, unsigned HOST_WIDE_INT count) +{ + enum machine_mode mode = TYPE_MODE (vectype); + + /* vect_permute_store_chain requires the group size to be a power of two. */ + if (exact_log2 (count) == -1) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "the size of the group of accesses" + " is not a power of 2"); + return false; + } + + /* Check that the permutation is supported. */ + if (VECTOR_MODE_P (mode)) + { + unsigned int i, nelt = GET_MODE_NUNITS (mode); + unsigned char *sel = XALLOCAVEC (unsigned char, nelt); + for (i = 0; i < nelt / 2; i++) + { + sel[i * 2] = i; + sel[i * 2 + 1] = i + nelt; + } + if (can_vec_perm_p (mode, false, sel)) + { + for (i = 0; i < nelt; i++) + sel[i] += nelt / 2; + if (can_vec_perm_p (mode, false, sel)) + return true; + } + } + + if (dump_enabled_p ()) + dump_printf (MSG_MISSED_OPTIMIZATION, + "interleave op not supported by target."); + return false; +} + + +/* Return TRUE if vec_store_lanes is available for COUNT vectors of + type VECTYPE. */ + +bool +vect_store_lanes_supported (tree vectype, unsigned HOST_WIDE_INT count) +{ + return vect_lanes_optab_supported_p ("vec_store_lanes", + vec_store_lanes_optab, + vectype, count); +} + + +/* Function vect_permute_store_chain. + + Given a chain of interleaved stores in DR_CHAIN of LENGTH that must be + a power of 2, generate interleave_high/low stmts to reorder the data + correctly for the stores. Return the final references for stores in + RESULT_CHAIN. + + E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8. + The input is 4 vectors each containing 8 elements. We assign a number to + each element, the input sequence is: + + 1st vec: 0 1 2 3 4 5 6 7 + 2nd vec: 8 9 10 11 12 13 14 15 + 3rd vec: 16 17 18 19 20 21 22 23 + 4th vec: 24 25 26 27 28 29 30 31 + + The output sequence should be: + + 1st vec: 0 8 16 24 1 9 17 25 + 2nd vec: 2 10 18 26 3 11 19 27 + 3rd vec: 4 12 20 28 5 13 21 30 + 4th vec: 6 14 22 30 7 15 23 31 + + i.e., we interleave the contents of the four vectors in their order. + + We use interleave_high/low instructions to create such output. The input of + each interleave_high/low operation is two vectors: + 1st vec 2nd vec + 0 1 2 3 4 5 6 7 + the even elements of the result vector are obtained left-to-right from the + high/low elements of the first vector. The odd elements of the result are + obtained left-to-right from the high/low elements of the second vector. + The output of interleave_high will be: 0 4 1 5 + and of interleave_low: 2 6 3 7 + + + The permutation is done in log LENGTH stages. In each stage interleave_high + and interleave_low stmts are created for each pair of vectors in DR_CHAIN, + where the first argument is taken from the first half of DR_CHAIN and the + second argument from it's second half. + In our example, + + I1: interleave_high (1st vec, 3rd vec) + I2: interleave_low (1st vec, 3rd vec) + I3: interleave_high (2nd vec, 4th vec) + I4: interleave_low (2nd vec, 4th vec) + + The output for the first stage is: + + I1: 0 16 1 17 2 18 3 19 + I2: 4 20 5 21 6 22 7 23 + I3: 8 24 9 25 10 26 11 27 + I4: 12 28 13 29 14 30 15 31 + + The output of the second stage, i.e. the final result is: + + I1: 0 8 16 24 1 9 17 25 + I2: 2 10 18 26 3 11 19 27 + I3: 4 12 20 28 5 13 21 30 + I4: 6 14 22 30 7 15 23 31. */ + +void +vect_permute_store_chain (vec<tree> dr_chain, + unsigned int length, + gimple stmt, + gimple_stmt_iterator *gsi, + vec<tree> *result_chain) +{ + tree vect1, vect2, high, low; + gimple perm_stmt; + tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); + tree perm_mask_low, perm_mask_high; + unsigned int i, n; + unsigned int j, nelt = TYPE_VECTOR_SUBPARTS (vectype); + unsigned char *sel = XALLOCAVEC (unsigned char, nelt); + + result_chain->quick_grow (length); + memcpy (result_chain->address (), dr_chain.address (), + length * sizeof (tree)); + + for (i = 0, n = nelt / 2; i < n; i++) + { + sel[i * 2] = i; + sel[i * 2 + 1] = i + nelt; + } + perm_mask_high = vect_gen_perm_mask (vectype, sel); + gcc_assert (perm_mask_high != NULL); + + for (i = 0; i < nelt; i++) + sel[i] += nelt / 2; + perm_mask_low = vect_gen_perm_mask (vectype, sel); + gcc_assert (perm_mask_low != NULL); + + for (i = 0, n = exact_log2 (length); i < n; i++) + { + for (j = 0; j < length/2; j++) + { + vect1 = dr_chain[j]; + vect2 = dr_chain[j+length/2]; + + /* Create interleaving stmt: + high = VEC_PERM_EXPR <vect1, vect2, {0, nelt, 1, nelt+1, ...}> */ + high = make_temp_ssa_name (vectype, NULL, "vect_inter_high"); + perm_stmt + = gimple_build_assign_with_ops (VEC_PERM_EXPR, high, + vect1, vect2, perm_mask_high); + vect_finish_stmt_generation (stmt, perm_stmt, gsi); + (*result_chain)[2*j] = high; + + /* Create interleaving stmt: + low = VEC_PERM_EXPR <vect1, vect2, {nelt/2, nelt*3/2, nelt/2+1, + nelt*3/2+1, ...}> */ + low = make_temp_ssa_name (vectype, NULL, "vect_inter_low"); + perm_stmt + = gimple_build_assign_with_ops (VEC_PERM_EXPR, low, + vect1, vect2, perm_mask_low); + vect_finish_stmt_generation (stmt, perm_stmt, gsi); + (*result_chain)[2*j+1] = low; + } + memcpy (dr_chain.address (), result_chain->address (), + length * sizeof (tree)); + } +} + +/* Function vect_setup_realignment + + This function is called when vectorizing an unaligned load using + the dr_explicit_realign[_optimized] scheme. + This function generates the following code at the loop prolog: + + p = initial_addr; + x msq_init = *(floor(p)); # prolog load + realignment_token = call target_builtin; + loop: + x msq = phi (msq_init, ---) + + The stmts marked with x are generated only for the case of + dr_explicit_realign_optimized. + + The code above sets up a new (vector) pointer, pointing to the first + location accessed by STMT, and a "floor-aligned" load using that pointer. + It also generates code to compute the "realignment-token" (if the relevant + target hook was defined), and creates a phi-node at the loop-header bb + whose arguments are the result of the prolog-load (created by this + function) and the result of a load that takes place in the loop (to be + created by the caller to this function). + + For the case of dr_explicit_realign_optimized: + The caller to this function uses the phi-result (msq) to create the + realignment code inside the loop, and sets up the missing phi argument, + as follows: + loop: + msq = phi (msq_init, lsq) + lsq = *(floor(p')); # load in loop + result = realign_load (msq, lsq, realignment_token); + + For the case of dr_explicit_realign: + loop: + msq = *(floor(p)); # load in loop + p' = p + (VS-1); + lsq = *(floor(p')); # load in loop + result = realign_load (msq, lsq, realignment_token); + + Input: + STMT - (scalar) load stmt to be vectorized. This load accesses + a memory location that may be unaligned. + BSI - place where new code is to be inserted. + ALIGNMENT_SUPPORT_SCHEME - which of the two misalignment handling schemes + is used. + + Output: + REALIGNMENT_TOKEN - the result of a call to the builtin_mask_for_load + target hook, if defined. + Return value - the result of the loop-header phi node. */ + +tree +vect_setup_realignment (gimple stmt, gimple_stmt_iterator *gsi, + tree *realignment_token, + enum dr_alignment_support alignment_support_scheme, + tree init_addr, + struct loop **at_loop) +{ + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); + struct loop *loop = NULL; + edge pe = NULL; + tree scalar_dest = gimple_assign_lhs (stmt); + tree vec_dest; + gimple inc; + tree ptr; + tree data_ref; + gimple new_stmt; + basic_block new_bb; + tree msq_init = NULL_TREE; + tree new_temp; + gimple phi_stmt; + tree msq = NULL_TREE; + gimple_seq stmts = NULL; + bool inv_p; + bool compute_in_loop = false; + bool nested_in_vect_loop = false; + struct loop *containing_loop = (gimple_bb (stmt))->loop_father; + struct loop *loop_for_initial_load = NULL; + + if (loop_vinfo) + { + loop = LOOP_VINFO_LOOP (loop_vinfo); + nested_in_vect_loop = nested_in_vect_loop_p (loop, stmt); + } + + gcc_assert (alignment_support_scheme == dr_explicit_realign + || alignment_support_scheme == dr_explicit_realign_optimized); + + /* We need to generate three things: + 1. the misalignment computation + 2. the extra vector load (for the optimized realignment scheme). + 3. the phi node for the two vectors from which the realignment is + done (for the optimized realignment scheme). */ + + /* 1. Determine where to generate the misalignment computation. + + If INIT_ADDR is NULL_TREE, this indicates that the misalignment + calculation will be generated by this function, outside the loop (in the + preheader). Otherwise, INIT_ADDR had already been computed for us by the + caller, inside the loop. + + Background: If the misalignment remains fixed throughout the iterations of + the loop, then both realignment schemes are applicable, and also the + misalignment computation can be done outside LOOP. This is because we are + vectorizing LOOP, and so the memory accesses in LOOP advance in steps that + are a multiple of VS (the Vector Size), and therefore the misalignment in + different vectorized LOOP iterations is always the same. + The problem arises only if the memory access is in an inner-loop nested + inside LOOP, which is now being vectorized using outer-loop vectorization. + This is the only case when the misalignment of the memory access may not + remain fixed throughout the iterations of the inner-loop (as explained in + detail in vect_supportable_dr_alignment). In this case, not only is the + optimized realignment scheme not applicable, but also the misalignment + computation (and generation of the realignment token that is passed to + REALIGN_LOAD) have to be done inside the loop. + + In short, INIT_ADDR indicates whether we are in a COMPUTE_IN_LOOP mode + or not, which in turn determines if the misalignment is computed inside + the inner-loop, or outside LOOP. */ + + if (init_addr != NULL_TREE || !loop_vinfo) + { + compute_in_loop = true; + gcc_assert (alignment_support_scheme == dr_explicit_realign); + } + + + /* 2. Determine where to generate the extra vector load. + + For the optimized realignment scheme, instead of generating two vector + loads in each iteration, we generate a single extra vector load in the + preheader of the loop, and in each iteration reuse the result of the + vector load from the previous iteration. In case the memory access is in + an inner-loop nested inside LOOP, which is now being vectorized using + outer-loop vectorization, we need to determine whether this initial vector + load should be generated at the preheader of the inner-loop, or can be + generated at the preheader of LOOP. If the memory access has no evolution + in LOOP, it can be generated in the preheader of LOOP. Otherwise, it has + to be generated inside LOOP (in the preheader of the inner-loop). */ + + if (nested_in_vect_loop) + { + tree outerloop_step = STMT_VINFO_DR_STEP (stmt_info); + bool invariant_in_outerloop = + (tree_int_cst_compare (outerloop_step, size_zero_node) == 0); + loop_for_initial_load = (invariant_in_outerloop ? loop : loop->inner); + } + else + loop_for_initial_load = loop; + if (at_loop) + *at_loop = loop_for_initial_load; + + if (loop_for_initial_load) + pe = loop_preheader_edge (loop_for_initial_load); + + /* 3. For the case of the optimized realignment, create the first vector + load at the loop preheader. */ + + if (alignment_support_scheme == dr_explicit_realign_optimized) + { + /* Create msq_init = *(floor(p1)) in the loop preheader */ + + gcc_assert (!compute_in_loop); + vec_dest = vect_create_destination_var (scalar_dest, vectype); + ptr = vect_create_data_ref_ptr (stmt, vectype, loop_for_initial_load, + NULL_TREE, &init_addr, NULL, &inc, + true, &inv_p); + new_temp = copy_ssa_name (ptr, NULL); + new_stmt = gimple_build_assign_with_ops + (BIT_AND_EXPR, new_temp, ptr, + build_int_cst (TREE_TYPE (ptr), + -(HOST_WIDE_INT)TYPE_ALIGN_UNIT (vectype))); + new_bb = gsi_insert_on_edge_immediate (pe, new_stmt); + gcc_assert (!new_bb); + data_ref + = build2 (MEM_REF, TREE_TYPE (vec_dest), new_temp, + build_int_cst (reference_alias_ptr_type (DR_REF (dr)), 0)); + new_stmt = gimple_build_assign (vec_dest, data_ref); + new_temp = make_ssa_name (vec_dest, new_stmt); + gimple_assign_set_lhs (new_stmt, new_temp); + if (pe) + { + new_bb = gsi_insert_on_edge_immediate (pe, new_stmt); + gcc_assert (!new_bb); + } + else + gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT); + + msq_init = gimple_assign_lhs (new_stmt); + } + + /* 4. Create realignment token using a target builtin, if available. + It is done either inside the containing loop, or before LOOP (as + determined above). */ + + if (targetm.vectorize.builtin_mask_for_load) + { + tree builtin_decl; + + /* Compute INIT_ADDR - the initial addressed accessed by this memref. */ + if (!init_addr) + { + /* Generate the INIT_ADDR computation outside LOOP. */ + init_addr = vect_create_addr_base_for_vector_ref (stmt, &stmts, + NULL_TREE, loop); + if (loop) + { + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + else + gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT); + } + + builtin_decl = targetm.vectorize.builtin_mask_for_load (); + new_stmt = gimple_build_call (builtin_decl, 1, init_addr); + vec_dest = + vect_create_destination_var (scalar_dest, + gimple_call_return_type (new_stmt)); + new_temp = make_ssa_name (vec_dest, new_stmt); + gimple_call_set_lhs (new_stmt, new_temp); + + if (compute_in_loop) + gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT); + else + { + /* Generate the misalignment computation outside LOOP. */ + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_on_edge_immediate (pe, new_stmt); + gcc_assert (!new_bb); + } + + *realignment_token = gimple_call_lhs (new_stmt); + + /* The result of the CALL_EXPR to this builtin is determined from + the value of the parameter and no global variables are touched + which makes the builtin a "const" function. Requiring the + builtin to have the "const" attribute makes it unnecessary + to call mark_call_clobbered. */ + gcc_assert (TREE_READONLY (builtin_decl)); + } + + if (alignment_support_scheme == dr_explicit_realign) + return msq; + + gcc_assert (!compute_in_loop); + gcc_assert (alignment_support_scheme == dr_explicit_realign_optimized); + + + /* 5. Create msq = phi <msq_init, lsq> in loop */ + + pe = loop_preheader_edge (containing_loop); + vec_dest = vect_create_destination_var (scalar_dest, vectype); + msq = make_ssa_name (vec_dest, NULL); + phi_stmt = create_phi_node (msq, containing_loop->header); + add_phi_arg (phi_stmt, msq_init, pe, UNKNOWN_LOCATION); + + return msq; +} + + +/* Function vect_grouped_load_supported. + + Returns TRUE if even and odd permutations are supported, + and FALSE otherwise. */ + +bool +vect_grouped_load_supported (tree vectype, unsigned HOST_WIDE_INT count) +{ + enum machine_mode mode = TYPE_MODE (vectype); + + /* vect_permute_load_chain requires the group size to be a power of two. */ + if (exact_log2 (count) == -1) + { + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "the size of the group of accesses" + " is not a power of 2"); + return false; + } + + /* Check that the permutation is supported. */ + if (VECTOR_MODE_P (mode)) + { + unsigned int i, nelt = GET_MODE_NUNITS (mode); + unsigned char *sel = XALLOCAVEC (unsigned char, nelt); + + for (i = 0; i < nelt; i++) + sel[i] = i * 2; + if (can_vec_perm_p (mode, false, sel)) + { + for (i = 0; i < nelt; i++) + sel[i] = i * 2 + 1; + if (can_vec_perm_p (mode, false, sel)) + return true; + } + } + + if (dump_enabled_p ()) + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + "extract even/odd not supported by target"); + return false; +} + +/* Return TRUE if vec_load_lanes is available for COUNT vectors of + type VECTYPE. */ + +bool +vect_load_lanes_supported (tree vectype, unsigned HOST_WIDE_INT count) +{ + return vect_lanes_optab_supported_p ("vec_load_lanes", + vec_load_lanes_optab, + vectype, count); +} + +/* Function vect_permute_load_chain. + + Given a chain of interleaved loads in DR_CHAIN of LENGTH that must be + a power of 2, generate extract_even/odd stmts to reorder the input data + correctly. Return the final references for loads in RESULT_CHAIN. + + E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8. + The input is 4 vectors each containing 8 elements. We assign a number to each + element, the input sequence is: + + 1st vec: 0 1 2 3 4 5 6 7 + 2nd vec: 8 9 10 11 12 13 14 15 + 3rd vec: 16 17 18 19 20 21 22 23 + 4th vec: 24 25 26 27 28 29 30 31 + + The output sequence should be: + + 1st vec: 0 4 8 12 16 20 24 28 + 2nd vec: 1 5 9 13 17 21 25 29 + 3rd vec: 2 6 10 14 18 22 26 30 + 4th vec: 3 7 11 15 19 23 27 31 + + i.e., the first output vector should contain the first elements of each + interleaving group, etc. + + We use extract_even/odd instructions to create such output. The input of + each extract_even/odd operation is two vectors + 1st vec 2nd vec + 0 1 2 3 4 5 6 7 + + and the output is the vector of extracted even/odd elements. The output of + extract_even will be: 0 2 4 6 + and of extract_odd: 1 3 5 7 + + + The permutation is done in log LENGTH stages. In each stage extract_even + and extract_odd stmts are created for each pair of vectors in DR_CHAIN in + their order. In our example, + + E1: extract_even (1st vec, 2nd vec) + E2: extract_odd (1st vec, 2nd vec) + E3: extract_even (3rd vec, 4th vec) + E4: extract_odd (3rd vec, 4th vec) + + The output for the first stage will be: + + E1: 0 2 4 6 8 10 12 14 + E2: 1 3 5 7 9 11 13 15 + E3: 16 18 20 22 24 26 28 30 + E4: 17 19 21 23 25 27 29 31 + + In order to proceed and create the correct sequence for the next stage (or + for the correct output, if the second stage is the last one, as in our + example), we first put the output of extract_even operation and then the + output of extract_odd in RESULT_CHAIN (which is then copied to DR_CHAIN). + The input for the second stage is: + + 1st vec (E1): 0 2 4 6 8 10 12 14 + 2nd vec (E3): 16 18 20 22 24 26 28 30 + 3rd vec (E2): 1 3 5 7 9 11 13 15 + 4th vec (E4): 17 19 21 23 25 27 29 31 + + The output of the second stage: + + E1: 0 4 8 12 16 20 24 28 + E2: 2 6 10 14 18 22 26 30 + E3: 1 5 9 13 17 21 25 29 + E4: 3 7 11 15 19 23 27 31 + + And RESULT_CHAIN after reordering: + + 1st vec (E1): 0 4 8 12 16 20 24 28 + 2nd vec (E3): 1 5 9 13 17 21 25 29 + 3rd vec (E2): 2 6 10 14 18 22 26 30 + 4th vec (E4): 3 7 11 15 19 23 27 31. */ + +static void +vect_permute_load_chain (vec<tree> dr_chain, + unsigned int length, + gimple stmt, + gimple_stmt_iterator *gsi, + vec<tree> *result_chain) +{ + tree data_ref, first_vect, second_vect; + tree perm_mask_even, perm_mask_odd; + gimple perm_stmt; + tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); + unsigned int i, j, log_length = exact_log2 (length); + unsigned nelt = TYPE_VECTOR_SUBPARTS (vectype); + unsigned char *sel = XALLOCAVEC (unsigned char, nelt); + + result_chain->quick_grow (length); + memcpy (result_chain->address (), dr_chain.address (), + length * sizeof (tree)); + + for (i = 0; i < nelt; ++i) + sel[i] = i * 2; + perm_mask_even = vect_gen_perm_mask (vectype, sel); + gcc_assert (perm_mask_even != NULL); + + for (i = 0; i < nelt; ++i) + sel[i] = i * 2 + 1; + perm_mask_odd = vect_gen_perm_mask (vectype, sel); + gcc_assert (perm_mask_odd != NULL); + + for (i = 0; i < log_length; i++) + { + for (j = 0; j < length; j += 2) + { + first_vect = dr_chain[j]; + second_vect = dr_chain[j+1]; + + /* data_ref = permute_even (first_data_ref, second_data_ref); */ + data_ref = make_temp_ssa_name (vectype, NULL, "vect_perm_even"); + perm_stmt = gimple_build_assign_with_ops (VEC_PERM_EXPR, data_ref, + first_vect, second_vect, + perm_mask_even); + vect_finish_stmt_generation (stmt, perm_stmt, gsi); + (*result_chain)[j/2] = data_ref; + + /* data_ref = permute_odd (first_data_ref, second_data_ref); */ + data_ref = make_temp_ssa_name (vectype, NULL, "vect_perm_odd"); + perm_stmt = gimple_build_assign_with_ops (VEC_PERM_EXPR, data_ref, + first_vect, second_vect, + perm_mask_odd); + vect_finish_stmt_generation (stmt, perm_stmt, gsi); + (*result_chain)[j/2+length/2] = data_ref; + } + memcpy (dr_chain.address (), result_chain->address (), + length * sizeof (tree)); + } +} + + +/* Function vect_transform_grouped_load. + + Given a chain of input interleaved data-refs (in DR_CHAIN), build statements + to perform their permutation and ascribe the result vectorized statements to + the scalar statements. +*/ + +void +vect_transform_grouped_load (gimple stmt, vec<tree> dr_chain, int size, + gimple_stmt_iterator *gsi) +{ + vec<tree> result_chain = vNULL; + + /* DR_CHAIN contains input data-refs that are a part of the interleaving. + RESULT_CHAIN is the output of vect_permute_load_chain, it contains permuted + vectors, that are ready for vector computation. */ + result_chain.create (size); + vect_permute_load_chain (dr_chain, size, stmt, gsi, &result_chain); + vect_record_grouped_load_vectors (stmt, result_chain); + result_chain.release (); +} + +/* RESULT_CHAIN contains the output of a group of grouped loads that were + generated as part of the vectorization of STMT. Assign the statement + for each vector to the associated scalar statement. */ + +void +vect_record_grouped_load_vectors (gimple stmt, vec<tree> result_chain) +{ + gimple first_stmt = GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)); + gimple next_stmt, new_stmt; + unsigned int i, gap_count; + tree tmp_data_ref; + + /* Put a permuted data-ref in the VECTORIZED_STMT field. + Since we scan the chain starting from it's first node, their order + corresponds the order of data-refs in RESULT_CHAIN. */ + next_stmt = first_stmt; + gap_count = 1; + FOR_EACH_VEC_ELT (result_chain, i, tmp_data_ref) + { + if (!next_stmt) + break; + + /* Skip the gaps. Loads created for the gaps will be removed by dead + code elimination pass later. No need to check for the first stmt in + the group, since it always exists. + GROUP_GAP is the number of steps in elements from the previous + access (if there is no gap GROUP_GAP is 1). We skip loads that + correspond to the gaps. */ + if (next_stmt != first_stmt + && gap_count < GROUP_GAP (vinfo_for_stmt (next_stmt))) + { + gap_count++; + continue; + } + + while (next_stmt) + { + new_stmt = SSA_NAME_DEF_STMT (tmp_data_ref); + /* We assume that if VEC_STMT is not NULL, this is a case of multiple + copies, and we put the new vector statement in the first available + RELATED_STMT. */ + if (!STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt))) + STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt)) = new_stmt; + else + { + if (!GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt))) + { + gimple prev_stmt = + STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt)); + gimple rel_stmt = + STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt)); + while (rel_stmt) + { + prev_stmt = rel_stmt; + rel_stmt = + STMT_VINFO_RELATED_STMT (vinfo_for_stmt (rel_stmt)); + } + + STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt)) = + new_stmt; + } + } + + next_stmt = GROUP_NEXT_ELEMENT (vinfo_for_stmt (next_stmt)); + gap_count = 1; + /* If NEXT_STMT accesses the same DR as the previous statement, + put the same TMP_DATA_REF as its vectorized statement; otherwise + get the next data-ref from RESULT_CHAIN. */ + if (!next_stmt || !GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt))) + break; + } + } +} + +/* Function vect_force_dr_alignment_p. + + Returns whether the alignment of a DECL can be forced to be aligned + on ALIGNMENT bit boundary. */ + +bool +vect_can_force_dr_alignment_p (const_tree decl, unsigned int alignment) +{ + if (TREE_CODE (decl) != VAR_DECL) + return false; + + /* We cannot change alignment of common or external symbols as another + translation unit may contain a definition with lower alignment. + The rules of common symbol linking mean that the definition + will override the common symbol. The same is true for constant + pool entries which may be shared and are not properly merged + by LTO. */ + if (DECL_EXTERNAL (decl) + || DECL_COMMON (decl) + || DECL_IN_CONSTANT_POOL (decl)) + return false; + + if (TREE_ASM_WRITTEN (decl)) + return false; + + /* Do not override the alignment as specified by the ABI when the used + attribute is set. */ + if (DECL_PRESERVE_P (decl)) + return false; + + /* Do not override explicit alignment set by the user when an explicit + section name is also used. This is a common idiom used by many + software projects. */ + if (DECL_SECTION_NAME (decl) != NULL_TREE + && !DECL_HAS_IMPLICIT_SECTION_NAME_P (decl)) + return false; + + if (TREE_STATIC (decl)) + return (alignment <= MAX_OFILE_ALIGNMENT); + else + return (alignment <= MAX_STACK_ALIGNMENT); +} + + +/* Return whether the data reference DR is supported with respect to its + alignment. + If CHECK_ALIGNED_ACCESSES is TRUE, check if the access is supported even + it is aligned, i.e., check if it is possible to vectorize it with different + alignment. */ + +enum dr_alignment_support +vect_supportable_dr_alignment (struct data_reference *dr, + bool check_aligned_accesses) +{ + gimple stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (stmt); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + enum machine_mode mode = TYPE_MODE (vectype); + loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); + struct loop *vect_loop = NULL; + bool nested_in_vect_loop = false; + + if (aligned_access_p (dr) && !check_aligned_accesses) + return dr_aligned; + + if (loop_vinfo) + { + vect_loop = LOOP_VINFO_LOOP (loop_vinfo); + nested_in_vect_loop = nested_in_vect_loop_p (vect_loop, stmt); + } + + /* Possibly unaligned access. */ + + /* We can choose between using the implicit realignment scheme (generating + a misaligned_move stmt) and the explicit realignment scheme (generating + aligned loads with a REALIGN_LOAD). There are two variants to the + explicit realignment scheme: optimized, and unoptimized. + We can optimize the realignment only if the step between consecutive + vector loads is equal to the vector size. Since the vector memory + accesses advance in steps of VS (Vector Size) in the vectorized loop, it + is guaranteed that the misalignment amount remains the same throughout the + execution of the vectorized loop. Therefore, we can create the + "realignment token" (the permutation mask that is passed to REALIGN_LOAD) + at the loop preheader. + + However, in the case of outer-loop vectorization, when vectorizing a + memory access in the inner-loop nested within the LOOP that is now being + vectorized, while it is guaranteed that the misalignment of the + vectorized memory access will remain the same in different outer-loop + iterations, it is *not* guaranteed that is will remain the same throughout + the execution of the inner-loop. This is because the inner-loop advances + with the original scalar step (and not in steps of VS). If the inner-loop + step happens to be a multiple of VS, then the misalignment remains fixed + and we can use the optimized realignment scheme. For example: + + for (i=0; i<N; i++) + for (j=0; j<M; j++) + s += a[i+j]; + + When vectorizing the i-loop in the above example, the step between + consecutive vector loads is 1, and so the misalignment does not remain + fixed across the execution of the inner-loop, and the realignment cannot + be optimized (as illustrated in the following pseudo vectorized loop): + + for (i=0; i<N; i+=4) + for (j=0; j<M; j++){ + vs += vp[i+j]; // misalignment of &vp[i+j] is {0,1,2,3,0,1,2,3,...} + // when j is {0,1,2,3,4,5,6,7,...} respectively. + // (assuming that we start from an aligned address). + } + + We therefore have to use the unoptimized realignment scheme: + + for (i=0; i<N; i+=4) + for (j=k; j<M; j+=4) + vs += vp[i+j]; // misalignment of &vp[i+j] is always k (assuming + // that the misalignment of the initial address is + // 0). + + The loop can then be vectorized as follows: + + for (k=0; k<4; k++){ + rt = get_realignment_token (&vp[k]); + for (i=0; i<N; i+=4){ + v1 = vp[i+k]; + for (j=k; j<M; j+=4){ + v2 = vp[i+j+VS-1]; + va = REALIGN_LOAD <v1,v2,rt>; + vs += va; + v1 = v2; + } + } + } */ + + if (DR_IS_READ (dr)) + { + bool is_packed = false; + tree type = (TREE_TYPE (DR_REF (dr))); + + if (optab_handler (vec_realign_load_optab, mode) != CODE_FOR_nothing + && (!targetm.vectorize.builtin_mask_for_load + || targetm.vectorize.builtin_mask_for_load ())) + { + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + if ((nested_in_vect_loop + && (TREE_INT_CST_LOW (DR_STEP (dr)) + != GET_MODE_SIZE (TYPE_MODE (vectype)))) + || !loop_vinfo) + return dr_explicit_realign; + else + return dr_explicit_realign_optimized; + } + if (!known_alignment_for_access_p (dr)) + is_packed = not_size_aligned (DR_REF (dr)); + + if (targetm.vectorize. + support_vector_misalignment (mode, type, + DR_MISALIGNMENT (dr), is_packed)) + /* Can't software pipeline the loads, but can at least do them. */ + return dr_unaligned_supported; + } + else + { + bool is_packed = false; + tree type = (TREE_TYPE (DR_REF (dr))); + + if (!known_alignment_for_access_p (dr)) + is_packed = not_size_aligned (DR_REF (dr)); + + if (targetm.vectorize. + support_vector_misalignment (mode, type, + DR_MISALIGNMENT (dr), is_packed)) + return dr_unaligned_supported; + } + + /* Unsupported. */ + return dr_unaligned_unsupported; +} |