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view gcc/tree-vect-data-refs.c @ 88:f214c1d5b862
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| author | Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Tue, 20 Dec 2011 18:53:46 +0900 |
| parents | f6334be47118 |
| children | 04ced10e8804 |
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/* Data References Analysis and Manipulation Utilities for Vectorization. Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 "tm.h" #include "ggc.h" #include "tree.h" #include "tm_p.h" #include "target.h" #include "basic-block.h" #include "tree-pretty-print.h" #include "gimple-pretty-print.h" #include "tree-flow.h" #include "tree-dump.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 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) == 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 != DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt))) return -1; while (next_stmt && next_stmt != stmt) { result++; next_stmt = DR_GROUP_NEXT_DR (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 = DR_GROUP_FIRST_DR (stmtinfo_b); next = DR_GROUP_NEXT_DR (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. */ DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra); DR_GROUP_NEXT_DR (stmtinfo_a) = next; return; } prev = next; next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)); } /* We got to the end of the list. Insert here. */ DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra); DR_GROUP_NEXT_DR (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 (!DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b)) { DR_GROUP_FIRST_DR (stmtinfo_a) = DR_STMT (drb); DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb); DR_GROUP_NEXT_DR (stmtinfo_b) = DR_STMT (dra); return; } /* 2. DRB is a part of a chain and DRA is not. */ if (!DR_GROUP_FIRST_DR (stmtinfo_a) && DR_GROUP_FIRST_DR (stmtinfo_b)) { DR_GROUP_FIRST_DR (stmtinfo_a) = DR_GROUP_FIRST_DR (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 (DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b)) { gimple old_first_stmt = DR_GROUP_FIRST_DR (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. */ DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb); DR_GROUP_NEXT_DR (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) { DR_GROUP_FIRST_DR (vinfo_for_stmt (tmp)) = DR_STMT (drb); tmp = DR_GROUP_NEXT_DR (vinfo_for_stmt (tmp)); } } else { /* Insert DRB in the list of DRA. */ vect_insert_into_interleaving_chain (drb, dra); DR_GROUP_FIRST_DR (stmtinfo_b) = DR_GROUP_FIRST_DR (stmtinfo_a); } return; } /* 4. both DRA and DRB are in some interleaving chains. */ first_a = DR_GROUP_FIRST_DR (stmtinfo_a); first_b = DR_GROUP_FIRST_DR (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 = DR_GROUP_FIRST_DR (stmtinfo_a); prev = DR_GROUP_FIRST_DR (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 = DR_GROUP_FIRST_DR (stmtinfo_b); prev = DR_GROUP_FIRST_DR (stmtinfo_a); first_stmt = first_a; } while (node) { node_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (node))); next = DR_GROUP_NEXT_DR (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. */ DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node; DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = next; prev = node; break; } prev = next; next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)); } if (!next) { /* We got to the end of the list. Insert here. */ DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node; DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = NULL; prev = node; } DR_GROUP_FIRST_DR (vinfo_for_stmt (node)) = first_stmt; node = DR_GROUP_NEXT_DR (vinfo_for_stmt (node)); } } /* Function vect_equal_offsets. Check if OFFSET1 and OFFSET2 are identical expressions. */ static bool vect_equal_offsets (tree offset1, tree offset2) { bool res; STRIP_NOPS (offset1); STRIP_NOPS (offset2); if (offset1 == offset2) return true; if (TREE_CODE (offset1) != TREE_CODE (offset2) || (!BINARY_CLASS_P (offset1) && !UNARY_CLASS_P (offset1))) return false; res = vect_equal_offsets (TREE_OPERAND (offset1, 0), TREE_OPERAND (offset2, 0)); if (!res || !BINARY_CLASS_P (offset1)) return res; res = vect_equal_offsets (TREE_OPERAND (offset1, 1), TREE_OPERAND (offset2, 1)); return res; } /* 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 ((DR_BASE_ADDRESS (dra) != DR_BASE_ADDRESS (drb) && (TREE_CODE (DR_BASE_ADDRESS (dra)) != ADDR_EXPR || TREE_CODE (DR_BASE_ADDRESS (drb)) != ADDR_EXPR || TREE_OPERAND (DR_BASE_ADDRESS (dra), 0) != TREE_OPERAND (DR_BASE_ADDRESS (drb),0))) || !vect_equal_offsets (DR_OFFSET (dra), DR_OFFSET (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 ((DR_BASE_ADDRESS (dra) != DR_BASE_ADDRESS (drb) && (TREE_CODE (DR_BASE_ADDRESS (dra)) != ADDR_EXPR || TREE_CODE (DR_BASE_ADDRESS (drb)) != ADDR_EXPR || TREE_OPERAND (DR_BASE_ADDRESS (dra), 0) != TREE_OPERAND (DR_BASE_ADDRESS (drb),0))) || !vect_equal_offsets (DR_OFFSET (dra), DR_OFFSET (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 (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "Detected interleaving "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } 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 (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "Detected interleaving "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } 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) || (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_i)) && DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_j)) && (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_i)) == DR_GROUP_FIRST_DR (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 (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "mark for run-time aliasing test between "); print_generic_expr (vect_dump, DR_REF (DDR_A (ddr)), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (DDR_B (ddr)), TDF_SLIM); } if (optimize_loop_nest_for_size_p (loop)) { if (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "versioning not supported when optimizing for size."); return false; } /* FORNOW: We don't support versioning with outer-loop vectorization. */ if (loop->inner) { if (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "versioning not yet supported for outer-loops."); return false; } VEC_safe_push (ddr_p, heap, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo), 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, bool *data_dependence_in_bb) { 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) { if (loop_vinfo) { if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "versioning for alias required: " "can't determine dependence between "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } /* 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 strided access. */ if (vect_check_interleaving (dra, drb)) return false; if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "can't determine dependence between "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } /* We do not vectorize basic blocks with write-write dependencies. */ if (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)) return true; /* We deal with read-write dependencies in basic blocks later (by verifying that all the loads in the basic block are before all the stores). */ *data_dependence_in_bb = 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 (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "determined dependence between "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } /* 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 (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "versioning for alias required: bad dist vector for "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } /* 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 (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v) { int dist = dist_v[loop_depth]; if (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "dependence distance = %d.", dist); if (dist == 0) { if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "dependence distance == 0 between "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } /* 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)) DR_GROUP_READ_WRITE_DEPENDENCE (stmtinfo_a) = true; else { if (DR_IS_READ (drb)) DR_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 (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "dependence distance negative."); continue; } if (abs (dist) >= 2 && abs (dist) < *max_vf) { /* The dependence distance requires reduction of the maximal vectorization factor. */ *max_vf = abs (dist); if (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "dependence distance >= VF."); continue; } if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { fprintf (vect_dump, "not vectorized, possible dependence " "between data-refs "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } 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, bool *data_dependence_in_bb) { unsigned int i; VEC (ddr_p, heap) *ddrs = NULL; struct data_dependence_relation *ddr; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== vect_analyze_dependences ==="); if (loop_vinfo) ddrs = LOOP_VINFO_DDRS (loop_vinfo); else ddrs = BB_VINFO_DDRS (bb_vinfo); FOR_EACH_VEC_ELT (ddr_p, ddrs, i, ddr) if (vect_analyze_data_ref_dependence (ddr, loop_vinfo, max_vf, data_dependence_in_bb)) 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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "vect_compute_data_ref_alignment:"); if (loop_vinfo) loop = LOOP_VINFO_LOOP (loop_vinfo); /* Initialize misalignment to unknown. */ SET_DR_MISALIGNMENT (dr, -1); 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 (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "inner 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 (vect_print_dump_info (REPORT_ALIGNMENT)) { fprintf (vect_dump, "Unknown alignment for access: "); print_generic_expr (vect_dump, base, TDF_SLIM); } 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)) base_aligned = true; else base_aligned = false; if (!base_aligned) { /* Do not change the alignment of global variables if flag_section_anchors is enabled. */ if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype)) || (TREE_STATIC (base) && flag_section_anchors)) { if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "can't force alignment of ref: "); print_generic_expr (vect_dump, ref, TDF_SLIM); } 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 (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "force alignment of "); print_generic_expr (vect_dump, ref, TDF_SLIM); } 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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "unexpected misalign value"); return false; } SET_DR_MISALIGNMENT (dr, TREE_INT_CST_LOW (misalign)); if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "misalign = %d bytes of ref ", DR_MISALIGNMENT (dr)); print_generic_expr (vect_dump, ref, TDF_SLIM); } 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, heap) *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 (data_reference_p, 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,heap) *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_STRIDED_ACCESS (stmt_info)) dr_size *= DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info))); if (STMT_VINFO_STRIDED_ACCESS (peel_stmt_info)) dr_peel_size *= DR_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 (dr_p, 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 &= GET_MODE_SIZE (TYPE_MODE (vectype)) - 1; SET_DR_MISALIGNMENT (dr, misal); return; } if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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, heap) *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 (data_reference_p, datarefs, i, dr) { gimple stmt = DR_STMT (dr); stmt_vec_info stmt_info = vinfo_for_stmt (stmt); /* For interleaving, only the alignment of the first access matters. Skip statements marked as not vectorizable. */ if ((STMT_VINFO_STRIDED_ACCESS (stmt_info) && DR_GROUP_FIRST_DR (stmt_info) != stmt) || !STMT_VINFO_VECTORIZABLE (stmt_info)) continue; supportable_dr_alignment = vect_supportable_dr_alignment (dr, false); if (!supportable_dr_alignment) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { if (DR_IS_READ (dr)) fprintf (vect_dump, "not vectorized: unsupported unaligned load."); else fprintf (vect_dump, "not vectorized: unsupported unaligned store."); print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM); } return false; } if (supportable_dr_alignment != dr_aligned && vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "Vectorizing an unaligned access."); } return true; } /* 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_STRIDED_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) % DR_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 (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "data size =" HOST_WIDE_INT_PRINT_DEC, elmsize); fprintf (vect_dump, ". misalignment = %d. ", DR_MISALIGNMENT (dr)); } if (DR_MISALIGNMENT (dr) % elmsize) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "data size does not divide the misalignment.\n"); return false; } } if (!known_alignment_for_access_p (dr)) { tree type = (TREE_TYPE (DR_REF (dr))); tree ba = DR_BASE_OBJECT (dr); bool is_packed = false; if (ba) is_packed = contains_packed_reference (ba); if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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) { 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; bool supportable_dr_alignment = vect_supportable_dr_alignment (dr, true); if (!supportable_dr_alignment) *inside_cost = VECT_MAX_COST; else { if (DR_IS_READ (dr)) vect_get_load_cost (dr, ncopies, true, inside_cost, outside_cost); else vect_get_store_cost (dr, ncopies, inside_cost); } if (vect_print_dump_info (REPORT_COST)) fprintf (vect_dump, "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) { 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, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); struct data_reference *dr; FOR_EACH_VEC_ELT (data_reference_p, 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_STRIDED_ACCESS (stmt_info) && DR_GROUP_FIRST_DR (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); SET_DR_MISALIGNMENT (dr, save_misalignment); } outside_cost += vect_get_known_peeling_cost (loop_vinfo, elem->npeel, &dummy, vect_get_single_scalar_iteraion_cost (loop_vinfo)); 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->peel_info.dr = elem->dr; min->peel_info.npeel = elem->npeel; } 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) { struct _vect_peel_extended_info res; res.peel_info.dr = NULL; 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; 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, heap) *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; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== 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 (data_reference_p, 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_STRIDED_ACCESS (stmt_info) && DR_GROUP_FIRST_DR (stmt_info) != stmt) 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 < VEC_length (dr_p, STMT_VINFO_SAME_ALIGN_REFS (stmt_info)) || !dr0) { same_align_drs_max = VEC_length (dr_p, STMT_VINFO_SAME_ALIGN_REFS (stmt_info)); 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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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; vect_get_data_access_cost (dr0, &load_inside_cost, &load_outside_cost); vect_get_data_access_cost (first_store, &store_inside_cost, &store_outside_cost); /* 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; VEC_iterate (dr_p, STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (first_store))), 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; VEC_iterate (dr_p, STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr0))), 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 && !VEC_length (dr_p, STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr0)))) && 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); 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_STRIDED_ACCESS (stmt_info)) npeel /= DR_GROUP_SIZE (stmt_info); if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "Try peeling by %d", npeel); } /* Ensure that all data refs can be vectorized after the peel. */ FOR_EACH_VEC_ELT (data_reference_p, 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_STRIDED_ACCESS (stmt_info) && DR_GROUP_FIRST_DR (stmt_info) != stmt) 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 return stat; } if (do_peeling) { /* (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 (data_reference_p, 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 (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "Alignment of access forced using peeling."); if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "Peeling for alignment will be applied."); stat = vect_verify_datarefs_alignment (loop_vinfo, NULL); gcc_assert (stat); return stat; } } /* (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 (data_reference_p, 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_STRIDED_ACCESS (stmt_info) && DR_GROUP_FIRST_DR (stmt_info) != stmt)) 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) || VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) >= (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; VEC_safe_push (gimple, heap, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), 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) VEC_truncate (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), 0); } if (do_versioning) { VEC(gimple,heap) *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 (gimple, 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 (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "Alignment of access forced using versioning."); } if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v) { int dist = dist_v[loop_depth]; if (vect_print_dump_info (REPORT_DR_DETAILS)) fprintf (vect_dump, "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. */ VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a), drb); VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_b), dra); if (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "accesses have the same alignment."); if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "dependence distance modulo vf == 0 between "); print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); } } } } /* 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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ==="); /* Mark groups of data references with same alignment using data dependence information. */ if (loop_vinfo) { VEC (ddr_p, heap) *ddrs = LOOP_VINFO_DDRS (loop_vinfo); struct data_dependence_relation *ddr; unsigned int i; FOR_EACH_VEC_ELT (ddr_p, ddrs, i, ddr) vect_find_same_alignment_drs (ddr, loop_vinfo); } if (!vect_compute_data_refs_alignment (loop_vinfo, bb_vinfo)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "not vectorized: can't calculate alignment for data ref."); return false; } return true; } /* Analyze groups of strided accesses: check that DR belongs to a group of strided accesses of legal size, step, etc. Detect gaps, single element interleaving, and other special cases. Set strided 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 stride; bool slp_impossible = false; /* For interleaving, STRIDE is STEP counted in elements, i.e., the size of the interleaving group (including gaps). */ stride = dr_step / type_size; /* Not consecutive access is possible only if it is a part of interleaving. */ if (!DR_GROUP_FIRST_DR (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 && stride > 0 && exact_log2 (stride) != -1) { DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = stmt; DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride; if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "Detected single element interleaving "); print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM); fprintf (vect_dump, " step "); print_generic_expr (vect_dump, step, TDF_SLIM); } return true; } if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "not consecutive access "); print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM); } if (bb_vinfo) { /* Mark the statement as unvectorizable. */ STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) = false; return true; } return false; } if (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) == stmt) { /* First stmt in the interleaving chain. Check the chain. */ gimple next = DR_GROUP_NEXT_DR (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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (next)) || DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (prev))) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "READ_WRITE dependence in interleaving."); return false; } /* For load use the same data-ref load. */ DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next)) = prev; prev = next; next = DR_GROUP_NEXT_DR (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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "interleaved store with gaps"); return false; } gaps += diff - 1; } /* Store the gap from the previous member of the group. If there is no gap in the access, DR_GROUP_GAP is always 1. */ DR_GROUP_GAP (vinfo_for_stmt (next)) = diff; prev_init = DR_INIT (data_ref); next = DR_GROUP_NEXT_DR (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 (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "interleaving size is greater than step for "); print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM); } 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 stride and the number of elements. When there is no gap, this difference should be 0. */ DR_GROUP_GAP (vinfo_for_stmt (stmt)) = stride - count; } else { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "interleaved store with gaps"); return false; } } /* Check that STEP is a multiple of type size. */ if (dr_step && (dr_step % type_size) != 0) { if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "step is not a multiple of type size: step "); print_generic_expr (vect_dump, step, TDF_SLIM); fprintf (vect_dump, " size "); print_generic_expr (vect_dump, TYPE_SIZE_UNIT (scalar_type), TDF_SLIM); } return false; } /* FORNOW: we handle only interleaving that is a power of 2. We don't fail here if it may be still possible to vectorize the group using SLP. If not, the size of the group will be checked in vect_analyze_operations, and the vectorization will fail. */ if (exact_log2 (stride) == -1) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "interleaving is not a power of 2"); if (slp_impossible) return false; } if (stride == 0) stride = count; DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "Detected interleaving of size %d", (int)stride); /* 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) VEC_safe_push (gimple, heap, LOOP_VINFO_STRIDED_STORES (loop_vinfo), stmt); if (bb_vinfo) VEC_safe_push (gimple, heap, BB_VINFO_STRIDED_STORES (bb_vinfo), stmt); } } 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 strided 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; HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step); if (loop_vinfo) loop = LOOP_VINFO_LOOP (loop_vinfo); if (loop_vinfo && !step) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "bad data-ref access in loop"); return false; } /* Don't allow invariant accesses in loops. */ if (loop_vinfo && dr_step == 0) return false; 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. */ DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL; /* For the rest of the analysis we use the outer-loop step. */ step = STMT_VINFO_DR_STEP (stmt_info); dr_step = TREE_INT_CST_LOW (step); if (dr_step == 0) { if (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "zero step in outer loop."); if (DR_IS_READ (dr)) return true; else return false; } } /* Consecutive? */ 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. */ DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL; return true; } if (loop && nested_in_vect_loop_p (loop, stmt)) { if (vect_print_dump_info (REPORT_ALIGNMENT)) fprintf (vect_dump, "strided access in outer loop."); return false; } /* 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, heap) *datarefs; struct data_reference *dr; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== 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 (data_reference_p, datarefs, i, dr) if (STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (DR_STMT (dr))) && !vect_analyze_data_ref_access (dr)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "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, heap) * ddrs = LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo); unsigned i, j; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== vect_prune_runtime_alias_test_list ==="); for (i = 0; i < VEC_length (ddr_p, ddrs); ) { bool found; ddr_p ddr_i; ddr_i = VEC_index (ddr_p, ddrs, i); found = false; for (j = 0; j < i; j++) { ddr_p ddr_j = VEC_index (ddr_p, ddrs, j); if (vect_vfa_range_equal (ddr_i, ddr_j)) { if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "found equal ranges "); print_generic_expr (vect_dump, DR_REF (DDR_A (ddr_i)), TDF_SLIM); fprintf (vect_dump, ", "); print_generic_expr (vect_dump, DR_REF (DDR_B (ddr_i)), TDF_SLIM); fprintf (vect_dump, " and "); print_generic_expr (vect_dump, DR_REF (DDR_A (ddr_j)), TDF_SLIM); fprintf (vect_dump, ", "); print_generic_expr (vect_dump, DR_REF (DDR_B (ddr_j)), TDF_SLIM); } found = true; break; } } if (found) { VEC_ordered_remove (ddr_p, ddrs, i); continue; } i++; } if (VEC_length (ddr_p, ddrs) > (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS)) { if (vect_print_dump_info (REPORT_DR_DETAILS)) { fprintf (vect_dump, "disable versioning for alias - max number of generated " "checks exceeded."); } VEC_truncate (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo), 0); 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, heap) *datarefs; struct data_reference *dr; tree scalar_type; bool res; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== 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 (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "not vectorized: loop contains function calls" " or data references that cannot be analyzed"); return false; } datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); } else { bb = BB_VINFO_BB (bb_vinfo); res = compute_data_dependences_for_bb (bb, true, &BB_VINFO_DATAREFS (bb_vinfo), &BB_VINFO_DDRS (bb_vinfo)); if (!res) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "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 (data_reference_p, datarefs, i, dr) { gimple stmt; stmt_vec_info stmt_info; tree base, offset, init; int vf; if (!dr || !DR_REF (dr)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "not vectorized: unhandled data-ref "); return false; } stmt = DR_STMT (dr); stmt_info = vinfo_for_stmt (stmt); /* Check that analysis of the data-ref succeeded. */ if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr) || !DR_STEP (dr)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { fprintf (vect_dump, "not vectorized: data ref analysis failed "); print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM); } if (bb_vinfo) { /* Mark the statement as not vectorizable. */ STMT_VINFO_VECTORIZABLE (stmt_info) = false; continue; } else return false; } if (TREE_CODE (DR_BASE_ADDRESS (dr)) == INTEGER_CST) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) fprintf (vect_dump, "not vectorized: base addr of dr is a " "constant"); if (bb_vinfo) { /* Mark the statement as not vectorizable. */ STMT_VINFO_VECTORIZABLE (stmt_info) = false; continue; } else return false; } base = unshare_expr (DR_BASE_ADDRESS (dr)); offset = unshare_expr (DR_OFFSET (dr)); init = unshare_expr (DR_INIT (dr)); if (stmt_can_throw_internal (stmt)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { fprintf (vect_dump, "not vectorized: statement can throw an " "exception "); print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM); } 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_build2 (POINTER_PLUS_EXPR, TREE_TYPE (base), base, fold_convert (sizetype, init))); if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "analyze in outer-loop: "); print_generic_expr (vect_dump, inner_base, TDF_SLIM); } 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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "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 (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "\touter base_address: "); print_generic_expr (vect_dump, STMT_VINFO_DR_BASE_ADDRESS (stmt_info), TDF_SLIM); fprintf (vect_dump, "\n\touter offset from base address: "); print_generic_expr (vect_dump, STMT_VINFO_DR_OFFSET (stmt_info), TDF_SLIM); fprintf (vect_dump, "\n\touter constant offset from base address: "); print_generic_expr (vect_dump, STMT_VINFO_DR_INIT (stmt_info), TDF_SLIM); fprintf (vect_dump, "\n\touter step: "); print_generic_expr (vect_dump, STMT_VINFO_DR_STEP (stmt_info), TDF_SLIM); fprintf (vect_dump, "\n\touter aligned to: "); print_generic_expr (vect_dump, STMT_VINFO_DR_ALIGNED_TO (stmt_info), TDF_SLIM); } } if (STMT_VINFO_DATA_REF (stmt_info)) { if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { fprintf (vect_dump, "not vectorized: more than one data ref in stmt: "); print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM); } 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 (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS)) { fprintf (vect_dump, "not vectorized: no vectype for stmt: "); print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM); fprintf (vect_dump, " scalar_type: "); print_generic_expr (vect_dump, scalar_type, TDF_DETAILS); } if (bb_vinfo) { /* Mark the statement as not vectorizable. */ STMT_VINFO_VECTORIZABLE (stmt_info) = false; continue; } else 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; } 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_var (type, tmp); free (tmp); } else new_vect_var = create_tmp_var (type, prefix); /* Mark vector typed variable as a gimple register variable. */ if (TREE_CODE (type) == VECTOR_TYPE) DECL_GIMPLE_REG_P (new_vect_var) = true; 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)); tree 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 = build_fold_indirect_ref (data_ref_base); else { base_offset = ssize_int (0); init = ssize_int (0); base_name = build_fold_indirect_ref (unshare_expr (DR_REF (dr))); } data_ref_base_var = create_tmp_var (TREE_TYPE (data_ref_base), "batmp"); add_referenced_var (data_ref_base_var); 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"); add_referenced_var (dest); 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"); add_referenced_var (tmp); 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_build2 (POINTER_PLUS_EXPR, TREE_TYPE (data_ref_base), 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, get_name (base_name)); add_referenced_var (addr_expr); 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) { SSA_NAME_PTR_INFO (vec_stmt)->align = 1; SSA_NAME_PTR_INFO (vec_stmt)->misalign = 0; } } if (vect_print_dump_info (REPORT_DETAILS)) { fprintf (vect_dump, "created "); print_generic_expr (vect_dump, vec_stmt, TDF_SLIM); } return vec_stmt; } /* Function vect_create_data_ref_ptr. Create a new pointer to vector type (vp), 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 vector 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. AT_LOOP: the loop where the vector memref is to be created. 3. OFFSET (optional): an offset to be added to the initial address accessed by the data-ref in STMT. 4. ONLY_INIT: indicate if vp is to be updated in the loop, or remain pointing to the initial address. 5. TYPE: if not NULL indicates the required type of the data-ref. 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 *vp; vp = (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, struct loop *at_loop, tree offset, tree *initial_address, gimple *ptr_incr, bool only_init, bool *inv_p) { tree 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 vectype = STMT_VINFO_VECTYPE (stmt_info); tree vect_ptr_type; tree vect_ptr; tree new_temp; gimple vec_stmt; gimple_seq new_stmt_list = NULL; edge pe = NULL; basic_block new_bb; tree vect_ptr_init; struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); tree vptr; 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); gimple_stmt_iterator gsi = gsi_for_stmt (stmt); tree base; 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 = build_fold_indirect_ref (unshare_expr (DR_BASE_ADDRESS (dr))); if (vect_print_dump_info (REPORT_DETAILS)) { tree data_ref_base = base_name; fprintf (vect_dump, "create vector-pointer variable to type: "); print_generic_expr (vect_dump, vectype, TDF_SLIM); if (TREE_CODE (data_ref_base) == VAR_DECL || TREE_CODE (data_ref_base) == ARRAY_REF) fprintf (vect_dump, " vectorizing an array ref: "); else if (TREE_CODE (data_ref_base) == COMPONENT_REF) fprintf (vect_dump, " vectorizing a record based array ref: "); else if (TREE_CODE (data_ref_base) == SSA_NAME) fprintf (vect_dump, " vectorizing a pointer ref: "); print_generic_expr (vect_dump, base_name, TDF_SLIM); } /* (1) Create the new vector-pointer variable. */ vect_ptr_type = build_pointer_type (vectype); 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)))); vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, get_name (base_name)); /* Vector 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 vector data reference because it is not addressable. */ if (!alias_sets_conflict_p (get_deref_alias_set (vect_ptr), get_alias_set (DR_REF (dr)))) { vect_ptr_type = build_pointer_type_for_mode (vectype, TYPE_MODE (vect_ptr_type), true); vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, get_name (base_name)); } /* Likewise for any of the data references in the stmt group. */ else if (STMT_VINFO_DR_GROUP_SIZE (stmt_info) > 1) { gimple orig_stmt = STMT_VINFO_DR_GROUP_FIRST_DR (stmt_info); do { tree lhs = gimple_assign_lhs (orig_stmt); if (!alias_sets_conflict_p (get_deref_alias_set (vect_ptr), get_alias_set (lhs))) { vect_ptr_type = build_pointer_type_for_mode (vectype, TYPE_MODE (vect_ptr_type), true); vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, get_name (base_name)); break; } orig_stmt = STMT_VINFO_DR_GROUP_NEXT_DR (vinfo_for_stmt (orig_stmt)); } while (orig_stmt); } add_referenced_var (vect_ptr); /* 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 the vector-pointer, and set the vector-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 = (vectype *) initial_base */ if (TREE_CODE (new_temp) != SSA_NAME || !useless_type_conversion_p (vect_ptr_type, TREE_TYPE (new_temp))) { vec_stmt = gimple_build_assign (vect_ptr, fold_convert (vect_ptr_type, new_temp)); vect_ptr_init = make_ssa_name (vect_ptr, vec_stmt); /* Copy the points-to information if it exists. */ if (DR_PTR_INFO (dr)) duplicate_ssa_name_ptr_info (vect_ptr_init, DR_PTR_INFO (dr)); gimple_assign_set_lhs (vec_stmt, vect_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 vect_ptr_init = new_temp; /* (3) Handle the updating of the vector-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)) vptr = vect_ptr_init; else { /* The step of the vector pointer is the Vector Size. */ tree step = TYPE_SIZE_UNIT (vectype); /* 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 (vect_ptr_init, fold_convert (vect_ptr_type, step), vect_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; vptr = indx_before_incr; } if (!nested_in_vect_loop || only_init) return vptr; /* (4) Handle the updating of the vector-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 (vptr, fold_convert (vect_ptr_type, DR_STEP (dr)), vect_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 ptr_var = SSA_NAME_VAR (dataref_ptr); 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; incr_stmt = gimple_build_assign_with_ops (POINTER_PLUS_EXPR, ptr_var, dataref_ptr, update); new_dataref_ptr = make_ssa_name (ptr_var, incr_stmt); gimple_assign_set_lhs (incr_stmt, new_dataref_ptr); 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)); SSA_NAME_PTR_INFO (new_dataref_ptr)->align = 1; SSA_NAME_PTR_INFO (new_dataref_ptr)->misalign = 0; } 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); add_referenced_var (vec_dest); return vec_dest; } /* Function vect_strided_store_supported. Returns TRUE is INTERLEAVE_HIGH and INTERLEAVE_LOW operations are supported, and FALSE otherwise. */ bool vect_strided_store_supported (tree vectype) { optab interleave_high_optab, interleave_low_optab; enum machine_mode mode; mode = TYPE_MODE (vectype); /* Check that the operation is supported. */ interleave_high_optab = optab_for_tree_code (VEC_INTERLEAVE_HIGH_EXPR, vectype, optab_default); interleave_low_optab = optab_for_tree_code (VEC_INTERLEAVE_LOW_EXPR, vectype, optab_default); if (!interleave_high_optab || !interleave_low_optab) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "no optab for interleave."); return false; } if (optab_handler (interleave_high_optab, mode) == CODE_FOR_nothing || optab_handler (interleave_low_optab, mode) == CODE_FOR_nothing) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "interleave op not supported by target."); return false; } return true; } /* 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. */ bool vect_permute_store_chain (VEC(tree,heap) *dr_chain, unsigned int length, gimple stmt, gimple_stmt_iterator *gsi, VEC(tree,heap) **result_chain) { tree perm_dest, vect1, vect2, high, low; gimple perm_stmt; tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); int i; unsigned int j; enum tree_code high_code, low_code; /* Check that the operation is supported. */ if (!vect_strided_store_supported (vectype)) return false; *result_chain = VEC_copy (tree, heap, dr_chain); for (i = 0; i < exact_log2 (length); i++) { for (j = 0; j < length/2; j++) { vect1 = VEC_index (tree, dr_chain, j); vect2 = VEC_index (tree, dr_chain, j+length/2); /* Create interleaving stmt: in the case of big endian: high = interleave_high (vect1, vect2) and in the case of little endian: high = interleave_low (vect1, vect2). */ perm_dest = create_tmp_var (vectype, "vect_inter_high"); DECL_GIMPLE_REG_P (perm_dest) = 1; add_referenced_var (perm_dest); if (BYTES_BIG_ENDIAN) { high_code = VEC_INTERLEAVE_HIGH_EXPR; low_code = VEC_INTERLEAVE_LOW_EXPR; } else { low_code = VEC_INTERLEAVE_HIGH_EXPR; high_code = VEC_INTERLEAVE_LOW_EXPR; } perm_stmt = gimple_build_assign_with_ops (high_code, perm_dest, vect1, vect2); high = make_ssa_name (perm_dest, perm_stmt); gimple_assign_set_lhs (perm_stmt, high); vect_finish_stmt_generation (stmt, perm_stmt, gsi); VEC_replace (tree, *result_chain, 2*j, high); /* Create interleaving stmt: in the case of big endian: low = interleave_low (vect1, vect2) and in the case of little endian: low = interleave_high (vect1, vect2). */ perm_dest = create_tmp_var (vectype, "vect_inter_low"); DECL_GIMPLE_REG_P (perm_dest) = 1; add_referenced_var (perm_dest); perm_stmt = gimple_build_assign_with_ops (low_code, perm_dest, vect1, vect2); low = make_ssa_name (perm_dest, perm_stmt); gimple_assign_set_lhs (perm_stmt, low); vect_finish_stmt_generation (stmt, perm_stmt, gsi); VEC_replace (tree, *result_chain, 2*j+1, low); } dr_chain = VEC_copy (tree, heap, *result_chain); } return true; } /* 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, loop_for_initial_load, NULL_TREE, &init_addr, &inc, true, &inv_p); new_stmt = gimple_build_assign_with_ops (BIT_AND_EXPR, NULL_TREE, ptr, build_int_cst (TREE_TYPE (ptr), -(HOST_WIDE_INT)TYPE_ALIGN_UNIT (vectype))); new_temp = make_ssa_name (SSA_NAME_VAR (ptr), new_stmt); gimple_assign_set_lhs (new_stmt, new_temp); 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); mark_symbols_for_renaming (new_stmt); 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); SSA_NAME_DEF_STMT (msq) = phi_stmt; add_phi_arg (phi_stmt, msq_init, pe, UNKNOWN_LOCATION); return msq; } /* Function vect_strided_load_supported. Returns TRUE is EXTRACT_EVEN and EXTRACT_ODD operations are supported, and FALSE otherwise. */ bool vect_strided_load_supported (tree vectype) { optab perm_even_optab, perm_odd_optab; enum machine_mode mode; mode = TYPE_MODE (vectype); perm_even_optab = optab_for_tree_code (VEC_EXTRACT_EVEN_EXPR, vectype, optab_default); if (!perm_even_optab) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "no optab for perm_even."); return false; } if (optab_handler (perm_even_optab, mode) == CODE_FOR_nothing) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "perm_even op not supported by target."); return false; } perm_odd_optab = optab_for_tree_code (VEC_EXTRACT_ODD_EXPR, vectype, optab_default); if (!perm_odd_optab) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "no optab for perm_odd."); return false; } if (optab_handler (perm_odd_optab, mode) == CODE_FOR_nothing) { if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "perm_odd op not supported by target."); return false; } return true; } /* 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. */ bool vect_permute_load_chain (VEC(tree,heap) *dr_chain, unsigned int length, gimple stmt, gimple_stmt_iterator *gsi, VEC(tree,heap) **result_chain) { tree perm_dest, data_ref, first_vect, second_vect; gimple perm_stmt; tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); int i; unsigned int j; /* Check that the operation is supported. */ if (!vect_strided_load_supported (vectype)) return false; *result_chain = VEC_copy (tree, heap, dr_chain); for (i = 0; i < exact_log2 (length); i++) { for (j = 0; j < length; j +=2) { first_vect = VEC_index (tree, dr_chain, j); second_vect = VEC_index (tree, dr_chain, j+1); /* data_ref = permute_even (first_data_ref, second_data_ref); */ perm_dest = create_tmp_var (vectype, "vect_perm_even"); DECL_GIMPLE_REG_P (perm_dest) = 1; add_referenced_var (perm_dest); perm_stmt = gimple_build_assign_with_ops (VEC_EXTRACT_EVEN_EXPR, perm_dest, first_vect, second_vect); data_ref = make_ssa_name (perm_dest, perm_stmt); gimple_assign_set_lhs (perm_stmt, data_ref); vect_finish_stmt_generation (stmt, perm_stmt, gsi); mark_symbols_for_renaming (perm_stmt); VEC_replace (tree, *result_chain, j/2, data_ref); /* data_ref = permute_odd (first_data_ref, second_data_ref); */ perm_dest = create_tmp_var (vectype, "vect_perm_odd"); DECL_GIMPLE_REG_P (perm_dest) = 1; add_referenced_var (perm_dest); perm_stmt = gimple_build_assign_with_ops (VEC_EXTRACT_ODD_EXPR, perm_dest, first_vect, second_vect); data_ref = make_ssa_name (perm_dest, perm_stmt); gimple_assign_set_lhs (perm_stmt, data_ref); vect_finish_stmt_generation (stmt, perm_stmt, gsi); mark_symbols_for_renaming (perm_stmt); VEC_replace (tree, *result_chain, j/2+length/2, data_ref); } dr_chain = VEC_copy (tree, heap, *result_chain); } return true; } /* Function vect_transform_strided_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. */ bool vect_transform_strided_load (gimple stmt, VEC(tree,heap) *dr_chain, int size, gimple_stmt_iterator *gsi) { stmt_vec_info stmt_info = vinfo_for_stmt (stmt); gimple first_stmt = DR_GROUP_FIRST_DR (stmt_info); gimple next_stmt, new_stmt; VEC(tree,heap) *result_chain = NULL; unsigned int i, gap_count; tree tmp_data_ref; /* 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 = VEC_alloc (tree, heap, size); /* Permute. */ if (!vect_permute_load_chain (dr_chain, size, stmt, gsi, &result_chain)) return false; /* 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 (tree, 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. DR_GROUP_GAP is the number of steps in elements from the previous access (if there is no gap DR_GROUP_GAP is 1). We skip loads that correspond to the gaps. */ if (next_stmt != first_stmt && gap_count < DR_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 (!DR_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 = DR_GROUP_NEXT_DR (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 || !DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt))) break; } } VEC_free (tree, heap, result_chain); return true; } /* 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; if (DECL_EXTERNAL (decl)) return false; if (TREE_ASM_WRITTEN (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)) { tree ba = DR_BASE_OBJECT (dr); if (ba) is_packed = contains_packed_reference (ba); } 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)) { tree ba = DR_BASE_OBJECT (dr); if (ba) is_packed = contains_packed_reference (ba); } if (targetm.vectorize. support_vector_misalignment (mode, type, DR_MISALIGNMENT (dr), is_packed)) return dr_unaligned_supported; } /* Unsupported. */ return dr_unaligned_unsupported; }