/* Transformation Utilities for Loop Vectorization. Copyright (C) 2003,2004,2005 Free Software Foundation, Inc. Contributed by Dorit Naishlos 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 2, 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 COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "errors.h" #include "ggc.h" #include "tree.h" #include "target.h" #include "rtl.h" #include "basic-block.h" #include "diagnostic.h" #include "tree-flow.h" #include "tree-dump.h" #include "timevar.h" #include "cfgloop.h" #include "expr.h" #include "optabs.h" #include "tree-data-ref.h" #include "tree-chrec.h" #include "tree-scalar-evolution.h" #include "tree-vectorizer.h" #include "langhooks.h" #include "tree-pass.h" #include "toplev.h" /* Utility functions for the code transformation. */ static bool vect_transform_stmt (tree, block_stmt_iterator *); static void vect_align_data_ref (tree); static tree vect_create_destination_var (tree, tree); static tree vect_create_data_ref_ptr (tree, block_stmt_iterator *, tree, tree *, bool); static tree vect_create_index_for_vector_ref (loop_vec_info); static tree vect_create_addr_base_for_vector_ref (tree, tree *, tree); static tree vect_get_new_vect_var (tree, enum vect_var_kind, const char *); static tree vect_get_vec_def_for_operand (tree, tree); static tree vect_init_vector (tree, tree); static void vect_finish_stmt_generation (tree stmt, tree vec_stmt, block_stmt_iterator *bsi); static bool vect_is_simple_cond (tree, loop_vec_info); static void update_vuses_to_preheader (tree, struct loop*); /* Utility function dealing with loop peeling (not peeling itself). */ static void vect_generate_tmps_on_preheader (loop_vec_info, tree *, tree *, tree *); static tree vect_build_loop_niters (loop_vec_info); static void vect_update_ivs_after_vectorizer (loop_vec_info, tree, edge); static tree vect_gen_niters_for_prolog_loop (loop_vec_info, tree); static void vect_update_init_of_dr (struct data_reference *, tree niters); static void vect_update_inits_of_drs (loop_vec_info, tree); static void vect_do_peeling_for_alignment (loop_vec_info, struct loops *); static void vect_do_peeling_for_loop_bound (loop_vec_info, tree *, struct loops *); /* 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. */ static tree vect_get_new_vect_var (tree type, enum vect_var_kind var_kind, const char *name) { const char *prefix; tree new_vect_var; if (var_kind == vect_simple_var) prefix = "vect_"; else prefix = "vect_p"; if (name) new_vect_var = create_tmp_var (type, concat (prefix, name, NULL)); else new_vect_var = create_tmp_var (type, prefix); return new_vect_var; } /* Function vect_create_index_for_vector_ref. Create (and return) an index variable, along with it's update chain in the loop. This variable will be used to access a memory location in a vector operation. Input: LOOP: The loop being vectorized. BSI: The block_stmt_iterator where STMT is. Any new stmts created by this function can be added here, or in the loop pre-header. Output: Return an index that will be used to index a vector array. It is expected that a pointer to the first vector will be used as the base address for the indexed reference. FORNOW: we are not trying to be efficient, just creating a new index each time from scratch. At this time all vector references could use the same index. TODO: create only one index to be used by all vector references. Record the index in the LOOP_VINFO the first time this procedure is called and return it on subsequent calls. The increment of this index must be placed just before the conditional expression that ends the single block loop. */ static tree vect_create_index_for_vector_ref (loop_vec_info loop_vinfo) { tree init, step; block_stmt_iterator incr_bsi; bool insert_after; tree indx_before_incr, indx_after_incr; struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree incr; /* It is assumed that the base pointer used for vectorized access contains the address of the first vector. Therefore the index used for vectorized access must be initialized to zero and incremented by 1. */ init = integer_zero_node; step = integer_one_node; standard_iv_increment_position (loop, &incr_bsi, &insert_after); create_iv (init, step, NULL_TREE, loop, &incr_bsi, insert_after, &indx_before_incr, &indx_after_incr); incr = bsi_stmt (incr_bsi); get_stmt_operands (incr); set_stmt_info (stmt_ann (incr), new_stmt_vec_info (incr, loop_vinfo)); return indx_before_incr; } /* 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. 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. */ static tree vect_create_addr_base_for_vector_ref (tree stmt, tree *new_stmt_list, tree offset) { 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 (STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info)); tree base_name = build_fold_indirect_ref (data_ref_base); tree ref = DR_REF (dr); tree scalar_type = TREE_TYPE (ref); tree scalar_ptr_type = build_pointer_type (scalar_type); tree vec_stmt; tree new_temp; tree addr_base, addr_expr; tree dest, new_stmt; tree base_offset = unshare_expr (STMT_VINFO_VECT_INIT_OFFSET (stmt_info)); /* Create base_offset */ dest = create_tmp_var (TREE_TYPE (base_offset), "base_off"); add_referenced_tmp_var (dest); base_offset = force_gimple_operand (base_offset, &new_stmt, false, dest); append_to_statement_list_force (new_stmt, new_stmt_list); if (offset) { tree tmp = create_tmp_var (TREE_TYPE (base_offset), "offset"); add_referenced_tmp_var (tmp); offset = fold (build2 (MULT_EXPR, TREE_TYPE (offset), offset, STMT_VINFO_VECT_STEP (stmt_info))); base_offset = fold (build2 (PLUS_EXPR, TREE_TYPE (base_offset), base_offset, offset)); base_offset = force_gimple_operand (base_offset, &new_stmt, false, tmp); append_to_statement_list_force (new_stmt, new_stmt_list); } /* base + base_offset */ addr_base = fold (build2 (PLUS_EXPR, TREE_TYPE (data_ref_base), data_ref_base, base_offset)); /* addr_expr = addr_base */ addr_expr = vect_get_new_vect_var (scalar_ptr_type, vect_pointer_var, get_name (base_name)); add_referenced_tmp_var (addr_expr); vec_stmt = build2 (MODIFY_EXPR, void_type_node, addr_expr, addr_base); new_temp = make_ssa_name (addr_expr, vec_stmt); TREE_OPERAND (vec_stmt, 0) = new_temp; append_to_statement_list_force (vec_stmt, new_stmt_list); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "created "); print_generic_expr (vect_dump, vec_stmt, TDF_SLIM); } return new_temp; } /* Function vect_align_data_ref. Handle mislignment of a memory accesses. FORNOW: Can't handle misaligned accesses. Make sure that the dataref is aligned. */ static void vect_align_data_ref (tree stmt) { stmt_vec_info stmt_info = vinfo_for_stmt (stmt); struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info); /* FORNOW: can't handle misaligned accesses; all accesses expected to be aligned. */ gcc_assert (aligned_access_p (dr)); } /* Function vect_create_data_ref_ptr. Create a memory reference expression for vector access, to be used in a vector load/store stmt. The reference is based on a new pointer to vector type (vp). Input: 1. STMT: a stmt that references memory. Expected to be of the form MODIFY_EXPR or MODIFY_EXPR . 2. BSI: block_stmt_iterator where new stmts can be added. 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. 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. Create a data-reference in the loop based on the new vector pointer vp, and using a new index variable 'idx' as follows: vp' = vp + update where if ONLY_INIT is true: update = zero and otherwise update = idx + vector_type_size Return the pointer vp'. FORNOW: handle only aligned and consecutive accesses. */ static tree vect_create_data_ref_ptr (tree stmt, block_stmt_iterator *bsi, tree offset, tree *initial_address, bool only_init) { 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 = LOOP_VINFO_LOOP (loop_vinfo); tree vectype = STMT_VINFO_VECTYPE (stmt_info); tree vect_ptr_type; tree vect_ptr; tree tag; tree new_temp; tree vec_stmt; tree new_stmt_list = NULL_TREE; tree idx; edge pe = loop_preheader_edge (loop); basic_block new_bb; tree vect_ptr_init; tree vectype_size; tree ptr_update; tree data_ref_ptr; tree type, tmp, size; base_name = build_fold_indirect_ref (unshare_expr ( STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info))); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { tree data_ref_base = base_name; fprintf (vect_dump, "create array_ref of type: "); print_generic_expr (vect_dump, vectype, TDF_SLIM); if (TREE_CODE (data_ref_base) == VAR_DECL) fprintf (vect_dump, " vectorizing a one dimensional array ref: "); else if (TREE_CODE (data_ref_base) == ARRAY_REF) fprintf (vect_dump, " vectorizing a multidimensional 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); vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, get_name (base_name)); add_referenced_tmp_var (vect_ptr); /** (2) Add aliasing information to the new vector-pointer: (The points-to info (SSA_NAME_PTR_INFO) may be defined later.) **/ tag = STMT_VINFO_MEMTAG (stmt_info); gcc_assert (tag); /* If the memory tag of the original reference was not a type tag or if the pointed-to type of VECT_PTR has an alias set number different than TAG's, then we need to create a new type tag for VECT_PTR and add TAG to its alias set. */ if (var_ann (tag)->mem_tag_kind == NOT_A_TAG || get_alias_set (tag) != get_alias_set (TREE_TYPE (vect_ptr_type))) add_type_alias (vect_ptr, tag); else var_ann (vect_ptr)->type_mem_tag = tag; var_ann (vect_ptr)->subvars = STMT_VINFO_SUBVARS (stmt_info); /** (3) 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); pe = loop_preheader_edge (loop); new_bb = bsi_insert_on_edge_immediate (pe, new_stmt_list); gcc_assert (!new_bb); *initial_address = new_temp; /* Create: p = (vectype *) initial_base */ vec_stmt = fold_convert (vect_ptr_type, new_temp); vec_stmt = build2 (MODIFY_EXPR, void_type_node, vect_ptr, vec_stmt); new_temp = make_ssa_name (vect_ptr, vec_stmt); TREE_OPERAND (vec_stmt, 0) = new_temp; new_bb = bsi_insert_on_edge_immediate (pe, vec_stmt); gcc_assert (!new_bb); vect_ptr_init = TREE_OPERAND (vec_stmt, 0); /** (4) Handle the updating of the vector-pointer inside the loop: **/ if (only_init) /* No update in loop is required. */ { /* Copy the points-to information if it exists. */ if (STMT_VINFO_PTR_INFO (stmt_info)) duplicate_ssa_name_ptr_info (vect_ptr_init, STMT_VINFO_PTR_INFO (stmt_info)); return vect_ptr_init; } idx = vect_create_index_for_vector_ref (loop_vinfo); /* Create: update = idx * vectype_size */ tmp = create_tmp_var (integer_type_node, "update"); add_referenced_tmp_var (tmp); size = TYPE_SIZE (vect_ptr_type); type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1); ptr_update = create_tmp_var (type, "update"); add_referenced_tmp_var (ptr_update); vectype_size = TYPE_SIZE_UNIT (vectype); vec_stmt = build2 (MULT_EXPR, integer_type_node, idx, vectype_size); vec_stmt = build2 (MODIFY_EXPR, void_type_node, tmp, vec_stmt); new_temp = make_ssa_name (tmp, vec_stmt); TREE_OPERAND (vec_stmt, 0) = new_temp; bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT); vec_stmt = fold_convert (type, new_temp); vec_stmt = build2 (MODIFY_EXPR, void_type_node, ptr_update, vec_stmt); new_temp = make_ssa_name (ptr_update, vec_stmt); TREE_OPERAND (vec_stmt, 0) = new_temp; bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT); /* Create: data_ref_ptr = vect_ptr_init + update */ vec_stmt = build2 (PLUS_EXPR, vect_ptr_type, vect_ptr_init, new_temp); vec_stmt = build2 (MODIFY_EXPR, void_type_node, vect_ptr, vec_stmt); new_temp = make_ssa_name (vect_ptr, vec_stmt); TREE_OPERAND (vec_stmt, 0) = new_temp; bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT); data_ref_ptr = TREE_OPERAND (vec_stmt, 0); /* Copy the points-to information if it exists. */ if (STMT_VINFO_PTR_INFO (stmt_info)) duplicate_ssa_name_ptr_info (data_ref_ptr, STMT_VINFO_PTR_INFO (stmt_info)); return data_ref_ptr; } /* Function vect_create_destination_var. Create a new temporary of type VECTYPE. */ static tree vect_create_destination_var (tree scalar_dest, tree vectype) { tree vec_dest; const char *new_name; 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 (vectype, vect_simple_var, new_name); add_referenced_tmp_var (vec_dest); return vec_dest; } /* Function vect_init_vector. Insert a new stmt (INIT_STMT) that initializes a new vector variable with the vector elements of VECTOR_VAR. Return the DEF of INIT_STMT. It will be used in the vectorization of STMT. */ static tree vect_init_vector (tree stmt, tree vector_var) { stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt); loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo); struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree new_var; tree init_stmt; tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo); tree vec_oprnd; edge pe; tree new_temp; basic_block new_bb; new_var = vect_get_new_vect_var (vectype, vect_simple_var, "cst_"); add_referenced_tmp_var (new_var); init_stmt = build2 (MODIFY_EXPR, vectype, new_var, vector_var); new_temp = make_ssa_name (new_var, init_stmt); TREE_OPERAND (init_stmt, 0) = new_temp; pe = loop_preheader_edge (loop); new_bb = bsi_insert_on_edge_immediate (pe, init_stmt); gcc_assert (!new_bb); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "created new init_stmt: "); print_generic_expr (vect_dump, init_stmt, TDF_SLIM); } vec_oprnd = TREE_OPERAND (init_stmt, 0); return vec_oprnd; } /* Function vect_get_vec_def_for_operand. OP is an operand in STMT. This function returns a (vector) def that will be used in the vectorized stmt for STMT. In the case that OP is an SSA_NAME which is defined in the loop, then STMT_VINFO_VEC_STMT of the defining stmt holds the relevant def. In case OP is an invariant or constant, a new stmt that creates a vector def needs to be introduced. */ static tree vect_get_vec_def_for_operand (tree op, tree stmt) { tree vec_oprnd; tree vec_stmt; tree def_stmt; stmt_vec_info def_stmt_info = NULL; stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt); tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo); int nunits = TYPE_VECTOR_SUBPARTS (vectype); loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo); struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); basic_block bb; tree vec_inv; tree t = NULL_TREE; tree def; int i; if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "vect_get_vec_def_for_operand: "); print_generic_expr (vect_dump, op, TDF_SLIM); } /** ===> Case 1: operand is a constant. **/ if (TREE_CODE (op) == INTEGER_CST || TREE_CODE (op) == REAL_CST) { /* Create 'vect_cst_ = {cst,cst,...,cst}' */ tree vec_cst; /* Build a tree with vector elements. */ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "Create vector_cst. nunits = %d", nunits); for (i = nunits - 1; i >= 0; --i) { t = tree_cons (NULL_TREE, op, t); } vec_cst = build_vector (vectype, t); return vect_init_vector (stmt, vec_cst); } gcc_assert (TREE_CODE (op) == SSA_NAME); /** ===> Case 2: operand is an SSA_NAME - find the stmt that defines it. **/ def_stmt = SSA_NAME_DEF_STMT (op); def_stmt_info = vinfo_for_stmt (def_stmt); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "vect_get_vec_def_for_operand: def_stmt: "); print_generic_expr (vect_dump, def_stmt, TDF_SLIM); } /** ==> Case 2.1: operand is defined inside the loop. **/ if (def_stmt_info) { /* Get the def from the vectorized stmt. */ vec_stmt = STMT_VINFO_VEC_STMT (def_stmt_info); gcc_assert (vec_stmt); vec_oprnd = TREE_OPERAND (vec_stmt, 0); return vec_oprnd; } /** ==> Case 2.2: operand is defined by the loop-header phi-node - it is a reduction/induction. **/ bb = bb_for_stmt (def_stmt); if (TREE_CODE (def_stmt) == PHI_NODE && flow_bb_inside_loop_p (loop, bb)) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "reduction/induction - unsupported."); internal_error ("no support for reduction/induction"); /* FORNOW */ } /** ==> Case 2.3: operand is defined outside the loop - it is a loop invariant. */ switch (TREE_CODE (def_stmt)) { case PHI_NODE: def = PHI_RESULT (def_stmt); break; case MODIFY_EXPR: def = TREE_OPERAND (def_stmt, 0); break; case NOP_EXPR: def = TREE_OPERAND (def_stmt, 0); gcc_assert (IS_EMPTY_STMT (def_stmt)); def = op; break; default: if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "unsupported defining stmt: "); print_generic_expr (vect_dump, def_stmt, TDF_SLIM); } internal_error ("unsupported defining stmt"); } /* Build a tree with vector elements. Create 'vec_inv = {inv,inv,..,inv}' */ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "Create vector_inv."); for (i = nunits - 1; i >= 0; --i) { t = tree_cons (NULL_TREE, def, t); } vec_inv = build_constructor (vectype, t); return vect_init_vector (stmt, vec_inv); } /* Function vect_finish_stmt_generation. Insert a new stmt. */ static void vect_finish_stmt_generation (tree stmt, tree vec_stmt, block_stmt_iterator *bsi) { bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "add new stmt: "); print_generic_expr (vect_dump, vec_stmt, TDF_SLIM); } #ifdef ENABLE_CHECKING /* Make sure bsi points to the stmt that is being vectorized. */ gcc_assert (stmt == bsi_stmt (*bsi)); #endif #ifdef USE_MAPPED_LOCATION SET_EXPR_LOCATION (vec_stmt, EXPR_LOCATION (stmt)); #else SET_EXPR_LOCUS (vec_stmt, EXPR_LOCUS (stmt)); #endif } /* Function vectorizable_assignment. Check if STMT performs an assignment (copy) that can be vectorized. If VEC_STMT is also passed, vectorize the STMT: create a vectorized stmt to replace it, put it in VEC_STMT, and insert it at BSI. Return FALSE if not a vectorizable STMT, TRUE otherwise. */ bool vectorizable_assignment (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt) { tree vec_dest; tree scalar_dest; tree op; tree vec_oprnd; 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); tree new_temp; /* Is vectorizable assignment? */ if (TREE_CODE (stmt) != MODIFY_EXPR) return false; scalar_dest = TREE_OPERAND (stmt, 0); if (TREE_CODE (scalar_dest) != SSA_NAME) return false; op = TREE_OPERAND (stmt, 1); if (!vect_is_simple_use (op, loop_vinfo, NULL)) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "use not simple."); return false; } if (!vec_stmt) /* transformation not required. */ { STMT_VINFO_TYPE (stmt_info) = assignment_vec_info_type; return true; } /** Transform. **/ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "transform assignment."); /* Handle def. */ vec_dest = vect_create_destination_var (scalar_dest, vectype); /* Handle use. */ op = TREE_OPERAND (stmt, 1); vec_oprnd = vect_get_vec_def_for_operand (op, stmt); /* Arguments are ready. create the new vector stmt. */ *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, vec_oprnd); new_temp = make_ssa_name (vec_dest, *vec_stmt); TREE_OPERAND (*vec_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, *vec_stmt, bsi); return true; } /* Function vectorizable_operation. Check if STMT performs a binary or unary operation that can be vectorized. If VEC_STMT is also passed, vectorize the STMT: create a vectorized stmt to replace it, put it in VEC_STMT, and insert it at BSI. Return FALSE if not a vectorizable STMT, TRUE otherwise. */ bool vectorizable_operation (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt) { tree vec_dest; tree scalar_dest; tree operation; tree op0, op1 = NULL; tree vec_oprnd0, vec_oprnd1=NULL; 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); int i; enum tree_code code; enum machine_mode vec_mode; tree new_temp; int op_type; tree op; optab optab; /* Is STMT a vectorizable binary/unary operation? */ if (TREE_CODE (stmt) != MODIFY_EXPR) return false; if (TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME) return false; operation = TREE_OPERAND (stmt, 1); code = TREE_CODE (operation); optab = optab_for_tree_code (code, vectype); /* Support only unary or binary operations. */ op_type = TREE_CODE_LENGTH (code); if (op_type != unary_op && op_type != binary_op) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "num. args = %d (not unary/binary op).", op_type); return false; } for (i = 0; i < op_type; i++) { op = TREE_OPERAND (operation, i); if (!vect_is_simple_use (op, loop_vinfo, NULL)) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "use not simple."); return false; } } /* Supportable by target? */ if (!optab) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "no optab."); return false; } vec_mode = TYPE_MODE (vectype); if (optab->handlers[(int) vec_mode].insn_code == CODE_FOR_nothing) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "op not supported by target."); return false; } if (!vec_stmt) /* transformation not required. */ { STMT_VINFO_TYPE (stmt_info) = op_vec_info_type; return true; } /** Transform. **/ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "transform binary/unary operation."); /* Handle def. */ scalar_dest = TREE_OPERAND (stmt, 0); vec_dest = vect_create_destination_var (scalar_dest, vectype); /* Handle uses. */ op0 = TREE_OPERAND (operation, 0); vec_oprnd0 = vect_get_vec_def_for_operand (op0, stmt); if (op_type == binary_op) { op1 = TREE_OPERAND (operation, 1); vec_oprnd1 = vect_get_vec_def_for_operand (op1, stmt); } /* Arguments are ready. create the new vector stmt. */ if (op_type == binary_op) *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, build2 (code, vectype, vec_oprnd0, vec_oprnd1)); else *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, build1 (code, vectype, vec_oprnd0)); new_temp = make_ssa_name (vec_dest, *vec_stmt); TREE_OPERAND (*vec_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, *vec_stmt, bsi); return true; } /* Function vectorizable_store. Check if STMT defines a non scalar data-ref (array/pointer/structure) that can be vectorized. If VEC_STMT is also passed, vectorize the STMT: create a vectorized stmt to replace it, put it in VEC_STMT, and insert it at BSI. Return FALSE if not a vectorizable STMT, TRUE otherwise. */ bool vectorizable_store (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt) { tree scalar_dest; tree data_ref; tree op; tree vec_oprnd1; 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); loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); enum machine_mode vec_mode; tree dummy; enum dr_alignment_support alignment_support_cheme; v_may_def_optype v_may_defs; int nv_may_defs, i; /* Is vectorizable store? */ if (TREE_CODE (stmt) != MODIFY_EXPR) return false; scalar_dest = TREE_OPERAND (stmt, 0); if (TREE_CODE (scalar_dest) != ARRAY_REF && TREE_CODE (scalar_dest) != INDIRECT_REF) return false; op = TREE_OPERAND (stmt, 1); if (!vect_is_simple_use (op, loop_vinfo, NULL)) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "use not simple."); return false; } vec_mode = TYPE_MODE (vectype); /* FORNOW. In some cases can vectorize even if data-type not supported (e.g. - array initialization with 0). */ if (mov_optab->handlers[(int)vec_mode].insn_code == CODE_FOR_nothing) return false; if (!STMT_VINFO_DATA_REF (stmt_info)) return false; if (!vec_stmt) /* transformation not required. */ { STMT_VINFO_TYPE (stmt_info) = store_vec_info_type; return true; } /** Transform. **/ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "transform store"); alignment_support_cheme = vect_supportable_dr_alignment (dr); gcc_assert (alignment_support_cheme); gcc_assert (alignment_support_cheme == dr_aligned); /* FORNOW */ /* Handle use - get the vectorized def from the defining stmt. */ vec_oprnd1 = vect_get_vec_def_for_operand (op, stmt); /* Handle def. */ /* FORNOW: make sure the data reference is aligned. */ vect_align_data_ref (stmt); data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE, &dummy, false); data_ref = build_fold_indirect_ref (data_ref); /* Arguments are ready. create the new vector stmt. */ *vec_stmt = build2 (MODIFY_EXPR, vectype, data_ref, vec_oprnd1); vect_finish_stmt_generation (stmt, *vec_stmt, bsi); /* Copy the V_MAY_DEFS representing the aliasing of the original array element's definition to the vector's definition then update the defining statement. The original is being deleted so the same SSA_NAMEs can be used. */ copy_virtual_operands (*vec_stmt, stmt); v_may_defs = STMT_V_MAY_DEF_OPS (*vec_stmt); nv_may_defs = NUM_V_MAY_DEFS (v_may_defs); for (i = 0; i < nv_may_defs; i++) { tree ssa_name = V_MAY_DEF_RESULT (v_may_defs, i); SSA_NAME_DEF_STMT (ssa_name) = *vec_stmt; } return true; } /* vectorizable_load. Check if STMT reads a non scalar data-ref (array/pointer/structure) that can be vectorized. If VEC_STMT is also passed, vectorize the STMT: create a vectorized stmt to replace it, put it in VEC_STMT, and insert it at BSI. Return FALSE if not a vectorizable STMT, TRUE otherwise. */ bool vectorizable_load (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt) { tree scalar_dest; tree vec_dest = NULL; tree data_ref = NULL; tree op; 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 new_temp; int mode; tree init_addr; tree new_stmt; tree dummy; basic_block new_bb; loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); edge pe = loop_preheader_edge (loop); enum dr_alignment_support alignment_support_cheme; /* Is vectorizable load? */ if (TREE_CODE (stmt) != MODIFY_EXPR) return false; scalar_dest = TREE_OPERAND (stmt, 0); if (TREE_CODE (scalar_dest) != SSA_NAME) return false; op = TREE_OPERAND (stmt, 1); if (TREE_CODE (op) != ARRAY_REF && TREE_CODE (op) != INDIRECT_REF) return false; if (!STMT_VINFO_DATA_REF (stmt_info)) return false; mode = (int) TYPE_MODE (vectype); /* FORNOW. In some cases can vectorize even if data-type not supported (e.g. - data copies). */ if (mov_optab->handlers[mode].insn_code == CODE_FOR_nothing) { if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo))) fprintf (vect_dump, "Aligned load, but unsupported type."); return false; } if (!vec_stmt) /* transformation not required. */ { STMT_VINFO_TYPE (stmt_info) = load_vec_info_type; return true; } /** Transform. **/ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "transform load."); alignment_support_cheme = vect_supportable_dr_alignment (dr); gcc_assert (alignment_support_cheme); if (alignment_support_cheme == dr_aligned || alignment_support_cheme == dr_unaligned_supported) { /* Create: p = initial_addr; indx = 0; loop { vec_dest = *(p); indx = indx + 1; } */ vec_dest = vect_create_destination_var (scalar_dest, vectype); data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE, &dummy, false); if (aligned_access_p (dr)) data_ref = build_fold_indirect_ref (data_ref); else { int mis = DR_MISALIGNMENT (dr); tree tmis = (mis == -1 ? size_zero_node : size_int (mis)); tmis = size_binop (MULT_EXPR, tmis, size_int(BITS_PER_UNIT)); data_ref = build2 (MISALIGNED_INDIRECT_REF, vectype, data_ref, tmis); } new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref); new_temp = make_ssa_name (vec_dest, new_stmt); TREE_OPERAND (new_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, new_stmt, bsi); copy_virtual_operands (new_stmt, stmt); } else if (alignment_support_cheme == dr_unaligned_software_pipeline) { /* Create: p1 = initial_addr; msq_init = *(floor(p1)) p2 = initial_addr + VS - 1; magic = have_builtin ? builtin_result : initial_address; indx = 0; loop { p2' = p2 + indx * vectype_size lsq = *(floor(p2')) vec_dest = realign_load (msq, lsq, magic) indx = indx + 1; msq = lsq; } */ tree offset; tree magic; tree phi_stmt; tree msq_init; tree msq, lsq; tree dataref_ptr; tree params; /* <1> Create msq_init = *(floor(p1)) in the loop preheader */ vec_dest = vect_create_destination_var (scalar_dest, vectype); data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE, &init_addr, true); data_ref = build1 (ALIGN_INDIRECT_REF, vectype, data_ref); new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref); new_temp = make_ssa_name (vec_dest, new_stmt); TREE_OPERAND (new_stmt, 0) = new_temp; new_bb = bsi_insert_on_edge_immediate (pe, new_stmt); gcc_assert (!new_bb); msq_init = TREE_OPERAND (new_stmt, 0); copy_virtual_operands (new_stmt, stmt); update_vuses_to_preheader (new_stmt, loop); /* <2> Create lsq = *(floor(p2')) in the loop */ offset = build_int_cst (integer_type_node, TYPE_VECTOR_SUBPARTS (vectype)); offset = int_const_binop (MINUS_EXPR, offset, integer_one_node, 1); vec_dest = vect_create_destination_var (scalar_dest, vectype); dataref_ptr = vect_create_data_ref_ptr (stmt, bsi, offset, &dummy, false); data_ref = build1 (ALIGN_INDIRECT_REF, vectype, dataref_ptr); new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref); new_temp = make_ssa_name (vec_dest, new_stmt); TREE_OPERAND (new_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, new_stmt, bsi); lsq = TREE_OPERAND (new_stmt, 0); copy_virtual_operands (new_stmt, stmt); /* <3> */ if (targetm.vectorize.builtin_mask_for_load) { /* Create permutation mask, if required, in loop preheader. */ tree builtin_decl; params = build_tree_list (NULL_TREE, init_addr); vec_dest = vect_create_destination_var (scalar_dest, vectype); builtin_decl = targetm.vectorize.builtin_mask_for_load (); new_stmt = build_function_call_expr (builtin_decl, params); new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, new_stmt); new_temp = make_ssa_name (vec_dest, new_stmt); TREE_OPERAND (new_stmt, 0) = new_temp; new_bb = bsi_insert_on_edge_immediate (pe, new_stmt); gcc_assert (!new_bb); magic = TREE_OPERAND (new_stmt, 0); /* 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_vars_to_rename. */ gcc_assert (TREE_READONLY (builtin_decl)); } else { /* Use current address instead of init_addr for reduced reg pressure. */ magic = dataref_ptr; } /* <4> Create msq = phi in loop */ vec_dest = vect_create_destination_var (scalar_dest, vectype); msq = make_ssa_name (vec_dest, NULL_TREE); phi_stmt = create_phi_node (msq, loop->header); /* CHECKME */ SSA_NAME_DEF_STMT (msq) = phi_stmt; add_phi_arg (phi_stmt, msq_init, loop_preheader_edge (loop)); add_phi_arg (phi_stmt, lsq, loop_latch_edge (loop)); /* <5> Create in loop */ vec_dest = vect_create_destination_var (scalar_dest, vectype); new_stmt = build3 (REALIGN_LOAD_EXPR, vectype, msq, lsq, magic); new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, new_stmt); new_temp = make_ssa_name (vec_dest, new_stmt); TREE_OPERAND (new_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, new_stmt, bsi); } else gcc_unreachable (); *vec_stmt = new_stmt; return true; } /* Function vect_is_simple_cond. Input: LOOP - the loop that is being vectorized. COND - Condition that is checked for simple use. Returns whether a COND can be vectorized. Checks whether condition operands are supportable using vec_is_simple_use. */ static bool vect_is_simple_cond (tree cond, loop_vec_info loop_vinfo) { tree lhs, rhs; if (TREE_CODE_CLASS (TREE_CODE (cond)) != tcc_comparison) return false; lhs = TREE_OPERAND (cond, 0); rhs = TREE_OPERAND (cond, 1); if (TREE_CODE (lhs) == SSA_NAME) { tree lhs_def_stmt = SSA_NAME_DEF_STMT (lhs); if (!vect_is_simple_use (lhs, loop_vinfo, &lhs_def_stmt)) return false; } else if (TREE_CODE (lhs) != INTEGER_CST && TREE_CODE (lhs) != REAL_CST) return false; if (TREE_CODE (rhs) == SSA_NAME) { tree rhs_def_stmt = SSA_NAME_DEF_STMT (rhs); if (!vect_is_simple_use (rhs, loop_vinfo, &rhs_def_stmt)) return false; } else if (TREE_CODE (rhs) != INTEGER_CST && TREE_CODE (rhs) != REAL_CST) return false; return true; } /* vectorizable_condition. Check if STMT is conditional modify expression that can be vectorized. If VEC_STMT is also passed, vectorize the STMT: create a vectorized stmt using VEC_COND_EXPR to replace it, put it in VEC_STMT, and insert it at BSI. Return FALSE if not a vectorizable STMT, TRUE otherwise. */ bool vectorizable_condition (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt) { tree scalar_dest = NULL_TREE; tree vec_dest = NULL_TREE; tree op = NULL_TREE; tree cond_expr, then_clause, else_clause; stmt_vec_info stmt_info = vinfo_for_stmt (stmt); tree vectype = STMT_VINFO_VECTYPE (stmt_info); tree vec_cond_lhs, vec_cond_rhs, vec_then_clause, vec_else_clause; tree vec_compare, vec_cond_expr; tree new_temp; loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info); enum machine_mode vec_mode; if (!STMT_VINFO_RELEVANT_P (stmt_info)) return false; if (TREE_CODE (stmt) != MODIFY_EXPR) return false; op = TREE_OPERAND (stmt, 1); if (TREE_CODE (op) != COND_EXPR) return false; cond_expr = TREE_OPERAND (op, 0); then_clause = TREE_OPERAND (op, 1); else_clause = TREE_OPERAND (op, 2); if (!vect_is_simple_cond (cond_expr, loop_vinfo)) return false; if (TREE_CODE (then_clause) == SSA_NAME) { tree then_def_stmt = SSA_NAME_DEF_STMT (then_clause); if (!vect_is_simple_use (then_clause, loop_vinfo, &then_def_stmt)) return false; } else if (TREE_CODE (then_clause) != INTEGER_CST && TREE_CODE (then_clause) != REAL_CST) return false; if (TREE_CODE (else_clause) == SSA_NAME) { tree else_def_stmt = SSA_NAME_DEF_STMT (else_clause); if (!vect_is_simple_use (else_clause, loop_vinfo, &else_def_stmt)) return false; } else if (TREE_CODE (else_clause) != INTEGER_CST && TREE_CODE (else_clause) != REAL_CST) return false; vec_mode = TYPE_MODE (vectype); if (!vec_stmt) { STMT_VINFO_TYPE (stmt_info) = condition_vec_info_type; return expand_vec_cond_expr_p (op, vec_mode); } /* Transform */ /* Handle def. */ scalar_dest = TREE_OPERAND (stmt, 0); vec_dest = vect_create_destination_var (scalar_dest, vectype); /* Handle cond expr. */ vec_cond_lhs = vect_get_vec_def_for_operand (TREE_OPERAND (cond_expr, 0), stmt); vec_cond_rhs = vect_get_vec_def_for_operand (TREE_OPERAND (cond_expr, 1), stmt); vec_then_clause = vect_get_vec_def_for_operand (then_clause, stmt); vec_else_clause = vect_get_vec_def_for_operand (else_clause, stmt); /* Arguments are ready. create the new vector stmt. */ vec_compare = build2 (TREE_CODE (cond_expr), vectype, vec_cond_lhs, vec_cond_rhs); vec_cond_expr = build (VEC_COND_EXPR, vectype, vec_compare, vec_then_clause, vec_else_clause); *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, vec_cond_expr); new_temp = make_ssa_name (vec_dest, *vec_stmt); TREE_OPERAND (*vec_stmt, 0) = new_temp; vect_finish_stmt_generation (stmt, *vec_stmt, bsi); return true; } /* Function vect_transform_stmt. Create a vectorized stmt to replace STMT, and insert it at BSI. */ bool vect_transform_stmt (tree stmt, block_stmt_iterator *bsi) { bool is_store = false; tree vec_stmt = NULL_TREE; stmt_vec_info stmt_info = vinfo_for_stmt (stmt); bool done; switch (STMT_VINFO_TYPE (stmt_info)) { case op_vec_info_type: done = vectorizable_operation (stmt, bsi, &vec_stmt); gcc_assert (done); break; case assignment_vec_info_type: done = vectorizable_assignment (stmt, bsi, &vec_stmt); gcc_assert (done); break; case load_vec_info_type: done = vectorizable_load (stmt, bsi, &vec_stmt); gcc_assert (done); break; case store_vec_info_type: done = vectorizable_store (stmt, bsi, &vec_stmt); gcc_assert (done); is_store = true; break; case condition_vec_info_type: done = vectorizable_condition (stmt, bsi, &vec_stmt); gcc_assert (done); break; default: if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "stmt not supported."); gcc_unreachable (); } STMT_VINFO_VEC_STMT (stmt_info) = vec_stmt; return is_store; } /* This function builds ni_name = number of iterations loop executes on the loop preheader. */ static tree vect_build_loop_niters (loop_vec_info loop_vinfo) { tree ni_name, stmt, var; edge pe; struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo)); var = create_tmp_var (TREE_TYPE (ni), "niters"); add_referenced_tmp_var (var); ni_name = force_gimple_operand (ni, &stmt, false, var); pe = loop_preheader_edge (loop); if (stmt) { basic_block new_bb = bsi_insert_on_edge_immediate (pe, stmt); gcc_assert (!new_bb); } return ni_name; } /* This function generates the following statements: ni_name = number of iterations loop executes ratio = ni_name / vf ratio_mult_vf_name = ratio * vf and places them at the loop preheader edge. */ static void vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, tree *ni_name_ptr, tree *ratio_mult_vf_name_ptr, tree *ratio_name_ptr) { edge pe; basic_block new_bb; tree stmt, ni_name; tree var; tree ratio_name; tree ratio_mult_vf_name; struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree ni = LOOP_VINFO_NITERS (loop_vinfo); int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); tree log_vf = build_int_cst (unsigned_type_node, exact_log2 (vf)); pe = loop_preheader_edge (loop); /* Generate temporary variable that contains number of iterations loop executes. */ ni_name = vect_build_loop_niters (loop_vinfo); /* Create: ratio = ni >> log2(vf) */ var = create_tmp_var (TREE_TYPE (ni), "bnd"); add_referenced_tmp_var (var); ratio_name = make_ssa_name (var, NULL_TREE); stmt = build2 (MODIFY_EXPR, void_type_node, ratio_name, build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_name, log_vf)); SSA_NAME_DEF_STMT (ratio_name) = stmt; pe = loop_preheader_edge (loop); new_bb = bsi_insert_on_edge_immediate (pe, stmt); gcc_assert (!new_bb); /* Create: ratio_mult_vf = ratio << log2 (vf). */ var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf"); add_referenced_tmp_var (var); ratio_mult_vf_name = make_ssa_name (var, NULL_TREE); stmt = build2 (MODIFY_EXPR, void_type_node, ratio_mult_vf_name, build2 (LSHIFT_EXPR, TREE_TYPE (ratio_name), ratio_name, log_vf)); SSA_NAME_DEF_STMT (ratio_mult_vf_name) = stmt; pe = loop_preheader_edge (loop); new_bb = bsi_insert_on_edge_immediate (pe, stmt); gcc_assert (!new_bb); *ni_name_ptr = ni_name; *ratio_mult_vf_name_ptr = ratio_mult_vf_name; *ratio_name_ptr = ratio_name; return; } /* Function update_vuses_to_preheader. Input: STMT - a statement with potential VUSEs. LOOP - the loop whose preheader will contain STMT. It's possible to vectorize a loop even though an SSA_NAME from a VUSE appears to be defined in a V_MAY_DEF in another statement in a loop. One such case is when the VUSE is at the dereference of a __restricted__ pointer in a load and the V_MAY_DEF is at the dereference of a different __restricted__ pointer in a store. Vectorization may result in copy_virtual_uses being called to copy the problematic VUSE to a new statement that is being inserted in the loop preheader. This procedure is called to change the SSA_NAME in the new statement's VUSE from the SSA_NAME updated in the loop to the related SSA_NAME available on the path entering the loop. When this function is called, we have the following situation: # vuse S1: vload do { # name1 = phi < name0 , name2> # vuse S2: vload # name2 = vdef S3: vstore }while... Stmt S1 was created in the loop preheader block as part of misaligned-load handling. This function fixes the name of the vuse of S1 from 'name1' to 'name0'. */ static void update_vuses_to_preheader (tree stmt, struct loop *loop) { basic_block header_bb = loop->header; edge preheader_e = loop_preheader_edge (loop); vuse_optype vuses = STMT_VUSE_OPS (stmt); int nvuses = NUM_VUSES (vuses); int i; for (i = 0; i < nvuses; i++) { tree ssa_name = VUSE_OP (vuses, i); tree def_stmt = SSA_NAME_DEF_STMT (ssa_name); tree name_var = SSA_NAME_VAR (ssa_name); basic_block bb = bb_for_stmt (def_stmt); /* For a use before any definitions, def_stmt is a NOP_EXPR. */ if (!IS_EMPTY_STMT (def_stmt) && flow_bb_inside_loop_p (loop, bb)) { /* If the block containing the statement defining the SSA_NAME is in the loop then it's necessary to find the definition outside the loop using the PHI nodes of the header. */ tree phi; bool updated = false; for (phi = phi_nodes (header_bb); phi; phi = TREE_CHAIN (phi)) { if (SSA_NAME_VAR (PHI_RESULT (phi)) == name_var) { SET_VUSE_OP (vuses, i, PHI_ARG_DEF (phi, preheader_e->dest_idx)); updated = true; break; } } gcc_assert (updated); } } } /* Function vect_update_ivs_after_vectorizer. "Advance" the induction variables of LOOP to the value they should take after the execution of LOOP. This is currently necessary because the vectorizer does not handle induction variables that are used after the loop. Such a situation occurs when the last iterations of LOOP are peeled, because: 1. We introduced new uses after LOOP for IVs that were not originally used after LOOP: the IVs of LOOP are now used by an epilog loop. 2. LOOP is going to be vectorized; this means that it will iterate N/VF times, whereas the loop IVs should be bumped N times. Input: - LOOP - a loop that is going to be vectorized. The last few iterations of LOOP were peeled. - NITERS - the number of iterations that LOOP executes (before it is vectorized). i.e, the number of times the ivs should be bumped. - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path coming out from LOOP on which there are uses of the LOOP ivs (this is the path from LOOP->exit to epilog_loop->preheader). The new definitions of the ivs are placed in LOOP->exit. The phi args associated with the edge UPDATE_E in the bb UPDATE_E->dest are updated accordingly. Assumption 1: Like the rest of the vectorizer, this function assumes a single loop exit that has a single predecessor. Assumption 2: The phi nodes in the LOOP header and in update_bb are organized in the same order. Assumption 3: The access function of the ivs is simple enough (see vect_can_advance_ivs_p). This assumption will be relaxed in the future. Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path coming out of LOOP on which the ivs of LOOP are used (this is the path that leads to the epilog loop; other paths skip the epilog loop). This path starts with the edge UPDATE_E, and its destination (denoted update_bb) needs to have its phis updated. */ static void vect_update_ivs_after_vectorizer (loop_vec_info loop_vinfo, tree niters, edge update_e) { struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); basic_block exit_bb = loop->single_exit->dest; tree phi, phi1; basic_block update_bb = update_e->dest; /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */ /* Make sure there exists a single-predecessor exit bb: */ gcc_assert (single_pred_p (exit_bb)); for (phi = phi_nodes (loop->header), phi1 = phi_nodes (update_bb); phi && phi1; phi = PHI_CHAIN (phi), phi1 = PHI_CHAIN (phi1)) { tree access_fn = NULL; tree evolution_part; tree init_expr; tree step_expr; tree var, stmt, ni, ni_name; block_stmt_iterator last_bsi; /* Skip virtual phi's. */ if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) { if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "virtual phi. skip."); continue; } access_fn = analyze_scalar_evolution (loop, PHI_RESULT (phi)); gcc_assert (access_fn); evolution_part = unshare_expr (evolution_part_in_loop_num (access_fn, loop->num)); gcc_assert (evolution_part != NULL_TREE); /* FORNOW: We do not support IVs whose evolution function is a polynomial of degree >= 2 or exponential. */ gcc_assert (!tree_is_chrec (evolution_part)); step_expr = evolution_part; init_expr = unshare_expr (initial_condition_in_loop_num (access_fn, loop->num)); ni = build2 (PLUS_EXPR, TREE_TYPE (init_expr), build2 (MULT_EXPR, TREE_TYPE (niters), niters, step_expr), init_expr); var = create_tmp_var (TREE_TYPE (init_expr), "tmp"); add_referenced_tmp_var (var); ni_name = force_gimple_operand (ni, &stmt, false, var); /* Insert stmt into exit_bb. */ last_bsi = bsi_last (exit_bb); if (stmt) bsi_insert_before (&last_bsi, stmt, BSI_SAME_STMT); /* Fix phi expressions in the successor bb. */ SET_PHI_ARG_DEF (phi1, update_e->dest_idx, ni_name); } } /* Function vect_do_peeling_for_loop_bound Peel the last iterations of the loop represented by LOOP_VINFO. The peeled iterations form a new epilog loop. Given that the loop now iterates NITERS times, the new epilog loop iterates NITERS % VECTORIZATION_FACTOR times. The original loop will later be made to iterate NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO). */ static void vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio, struct loops *loops) { tree ni_name, ratio_mult_vf_name; struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); struct loop *new_loop; edge update_e; basic_block preheader; #ifdef ENABLE_CHECKING int loop_num; #endif if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "=== vect_transtorm_for_unknown_loop_bound ==="); /* Generate the following variables on the preheader of original loop: ni_name = number of iteration the original loop executes ratio = ni_name / vf ratio_mult_vf_name = ratio * vf */ vect_generate_tmps_on_preheader (loop_vinfo, &ni_name, &ratio_mult_vf_name, ratio); #ifdef ENABLE_CHECKING loop_num = loop->num; #endif new_loop = slpeel_tree_peel_loop_to_edge (loop, loops, loop->single_exit, ratio_mult_vf_name, ni_name, false); #ifdef ENABLE_CHECKING gcc_assert (new_loop); gcc_assert (loop_num == loop->num); slpeel_verify_cfg_after_peeling (loop, new_loop); #endif /* A guard that controls whether the new_loop is to be executed or skipped is placed in LOOP->exit. LOOP->exit therefore has two successors - one is the preheader of NEW_LOOP, where the IVs from LOOP are used. The other is a bb after NEW_LOOP, where these IVs are not used. Find the edge that is on the path where the LOOP IVs are used and need to be updated. */ preheader = loop_preheader_edge (new_loop)->src; if (EDGE_PRED (preheader, 0)->src == loop->single_exit->dest) update_e = EDGE_PRED (preheader, 0); else update_e = EDGE_PRED (preheader, 1); /* Update IVs of original loop as if they were advanced by ratio_mult_vf_name steps. */ vect_update_ivs_after_vectorizer (loop_vinfo, ratio_mult_vf_name, update_e); /* After peeling we have to reset scalar evolution analyzer. */ scev_reset (); return; } /* Function vect_gen_niters_for_prolog_loop Set the number of iterations for the loop represented by LOOP_VINFO to the minimum between LOOP_NITERS (the original iteration count of the loop) and the misalignment of DR - the data reference recorded in LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO). As a result, after the execution of this loop, the data reference DR will refer to an aligned location. The following computation is generated: If the misalignment of DR is known at compile time: addr_mis = int mis = DR_MISALIGNMENT (dr); Else, compute address misalignment in bytes: addr_mis = addr & (vectype_size - 1) prolog_niters = min ( LOOP_NITERS , (VF - addr_mis/elem_size)&(VF-1) ) (elem_size = element type size; an element is the scalar element whose type is the inner type of the vectype) */ static tree vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters) { struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo); int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree var, stmt; tree iters, iters_name; edge pe; basic_block new_bb; tree dr_stmt = DR_STMT (dr); stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt); tree vectype = STMT_VINFO_VECTYPE (stmt_info); int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT; tree vf_minus_1 = build_int_cst (unsigned_type_node, vf - 1); tree niters_type = TREE_TYPE (loop_niters); pe = loop_preheader_edge (loop); if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0) { int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo); int element_size = vectype_align/vf; int elem_misalign = byte_misalign / element_size; if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "known alignment = %d.", byte_misalign); iters = build_int_cst (niters_type, (vf - elem_misalign)&(vf-1)); } else { tree new_stmts = NULL_TREE; tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt, &new_stmts, NULL_TREE); tree ptr_type = TREE_TYPE (start_addr); tree size = TYPE_SIZE (ptr_type); tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1); tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1); tree elem_size_log = build_int_cst (unsigned_type_node, exact_log2 (vectype_align/vf)); tree vf_tree = build_int_cst (unsigned_type_node, vf); tree byte_misalign; tree elem_misalign; new_bb = bsi_insert_on_edge_immediate (pe, new_stmts); gcc_assert (!new_bb); /* Create: byte_misalign = addr & (vectype_size - 1) */ byte_misalign = build2 (BIT_AND_EXPR, type, start_addr, vectype_size_minus_1); /* Create: elem_misalign = byte_misalign / element_size */ elem_misalign = build2 (RSHIFT_EXPR, unsigned_type_node, byte_misalign, elem_size_log); /* Create: (niters_type) (VF - elem_misalign)&(VF - 1) */ iters = build2 (MINUS_EXPR, unsigned_type_node, vf_tree, elem_misalign); iters = build2 (BIT_AND_EXPR, unsigned_type_node, iters, vf_minus_1); iters = fold_convert (niters_type, iters); } /* Create: prolog_loop_niters = min (iters, loop_niters) */ /* If the loop bound is known at compile time we already verified that it is greater than vf; since the misalignment ('iters') is at most vf, there's no need to generate the MIN_EXPR in this case. */ if (TREE_CODE (loop_niters) != INTEGER_CST) iters = build2 (MIN_EXPR, niters_type, iters, loop_niters); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "niters for prolog loop: "); print_generic_expr (vect_dump, iters, TDF_SLIM); } var = create_tmp_var (niters_type, "prolog_loop_niters"); add_referenced_tmp_var (var); iters_name = force_gimple_operand (iters, &stmt, false, var); /* Insert stmt on loop preheader edge. */ if (stmt) { basic_block new_bb = bsi_insert_on_edge_immediate (pe, stmt); gcc_assert (!new_bb); } return iters_name; } /* Function vect_update_init_of_dr NITERS iterations were peeled from LOOP. DR represents a data reference in LOOP. This function updates the information recorded in DR to account for the fact that the first NITERS iterations had already been executed. Specifically, it updates the OFFSET field of stmt_info. */ static void vect_update_init_of_dr (struct data_reference *dr, tree niters) { stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr)); tree offset = STMT_VINFO_VECT_INIT_OFFSET (stmt_info); niters = fold (build2 (MULT_EXPR, TREE_TYPE (niters), niters, STMT_VINFO_VECT_STEP (stmt_info))); offset = fold (build2 (PLUS_EXPR, TREE_TYPE (offset), offset, niters)); STMT_VINFO_VECT_INIT_OFFSET (stmt_info) = offset; } /* Function vect_update_inits_of_drs NITERS iterations were peeled from the loop represented by LOOP_VINFO. This function updates the information recorded for the data references in the loop to account for the fact that the first NITERS iterations had already been executed. Specifically, it updates the initial_condition of the access_function of all the data_references in the loop. */ static void vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters) { unsigned int i; varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo); varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo); if (vect_dump && (dump_flags & TDF_DETAILS)) fprintf (vect_dump, "=== vect_update_inits_of_dr ==="); for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++) { struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i); vect_update_init_of_dr (dr, niters); } for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++) { struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i); vect_update_init_of_dr (dr, niters); } } /* Function vect_do_peeling_for_alignment Peel the first 'niters' iterations of the loop represented by LOOP_VINFO. 'niters' is set to the misalignment of one of the data references in the loop, thereby forcing it to refer to an aligned location at the beginning of the execution of this loop. The data reference for which we are peeling is recorded in LOOP_VINFO_UNALIGNED_DR. */ static void vect_do_peeling_for_alignment (loop_vec_info loop_vinfo, struct loops *loops) { struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); tree niters_of_prolog_loop, ni_name; tree n_iters; struct loop *new_loop; if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "=== vect_do_peeling_for_alignment ==="); ni_name = vect_build_loop_niters (loop_vinfo); niters_of_prolog_loop = vect_gen_niters_for_prolog_loop (loop_vinfo, ni_name); /* Peel the prolog loop and iterate it niters_of_prolog_loop. */ new_loop = slpeel_tree_peel_loop_to_edge (loop, loops, loop_preheader_edge (loop), niters_of_prolog_loop, ni_name, true); #ifdef ENABLE_CHECKING gcc_assert (new_loop); slpeel_verify_cfg_after_peeling (new_loop, loop); #endif /* Update number of times loop executes. */ n_iters = LOOP_VINFO_NITERS (loop_vinfo); LOOP_VINFO_NITERS (loop_vinfo) = fold (build2 (MINUS_EXPR, TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop)); /* Update the init conditions of the access functions of all data refs. */ vect_update_inits_of_drs (loop_vinfo, niters_of_prolog_loop); /* After peeling we have to reset scalar evolution analyzer. */ scev_reset (); return; } /* Function vect_transform_loop. The analysis phase has determined that the loop is vectorizable. Vectorize the loop - created vectorized stmts to replace the scalar stmts in the loop, and update the loop exit condition. */ void vect_transform_loop (loop_vec_info loop_vinfo, struct loops *loops ATTRIBUTE_UNUSED) { struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo); int nbbs = loop->num_nodes; block_stmt_iterator si; int i; tree ratio = NULL; int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "=== vec_transform_loop ==="); /* Peel the loop if there are data refs with unknown alignment. Only one data ref with unknown store is allowed. */ if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo)) vect_do_peeling_for_alignment (loop_vinfo, loops); /* If the loop has a symbolic number of iterations 'n' (i.e. it's not a compile time constant), or it is a constant that doesn't divide by the vectorization factor, then an epilog loop needs to be created. We therefore duplicate the loop: the original loop will be vectorized, and will compute the first (n/VF) iterations. The second copy of the loop will remain scalar and will compute the remaining (n%VF) iterations. (VF is the vectorization factor). */ if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) || (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) && LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0)) vect_do_peeling_for_loop_bound (loop_vinfo, &ratio, loops); else ratio = build_int_cst (TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)), LOOP_VINFO_INT_NITERS (loop_vinfo) / vectorization_factor); /* 1) Make sure the loop header has exactly two entries 2) Make sure we have a preheader basic block. */ gcc_assert (EDGE_COUNT (loop->header->preds) == 2); loop_split_edge_with (loop_preheader_edge (loop), NULL); /* FORNOW: the vectorizer supports only loops which body consist of one basic block (header + empty latch). When the vectorizer will support more involved loop forms, the order by which the BBs are traversed need to be reconsidered. */ for (i = 0; i < nbbs; i++) { basic_block bb = bbs[i]; for (si = bsi_start (bb); !bsi_end_p (si);) { tree stmt = bsi_stmt (si); stmt_vec_info stmt_info; bool is_store; if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) { fprintf (vect_dump, "------>vectorizing statement: "); print_generic_expr (vect_dump, stmt, TDF_SLIM); } stmt_info = vinfo_for_stmt (stmt); gcc_assert (stmt_info); if (!STMT_VINFO_RELEVANT_P (stmt_info)) { bsi_next (&si); continue; } #ifdef ENABLE_CHECKING /* FORNOW: Verify that all stmts operate on the same number of units and no inner unrolling is necessary. */ gcc_assert (TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info)) == vectorization_factor); #endif /* -------- vectorize statement ------------ */ if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC)) fprintf (vect_dump, "transform statement."); is_store = vect_transform_stmt (stmt, &si); if (is_store) { /* Free the attached stmt_vec_info and remove the stmt. */ stmt_ann_t ann = stmt_ann (stmt); free (stmt_info); set_stmt_info (ann, NULL); bsi_remove (&si); continue; } bsi_next (&si); } /* stmts in BB */ } /* BBs in loop */ slpeel_make_loop_iterate_ntimes (loop, ratio); if (vect_print_dump_info (REPORT_VECTORIZED_LOOPS, LOOP_LOC (loop_vinfo))) fprintf (vect_dump, "LOOP VECTORIZED."); }