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/* Matrix layout transformations. Copyright (C) 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. Contributed by Razya Ladelsky <razya@il.ibm.com> Originally written by Revital Eres and Mustafa Hagog. 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/>. */ /* Matrix flattening optimization tries to replace a N-dimensional matrix with its equivalent M-dimensional matrix, where M < N. This first implementation focuses on global matrices defined dynamically. When N==1, we actually flatten the whole matrix. For instance consider a two-dimensional array a [dim1] [dim2]. The code for allocating space for it usually looks like: a = (int **) malloc(dim1 * sizeof(int *)); for (i=0; i<dim1; i++) a[i] = (int *) malloc (dim2 * sizeof(int)); If the array "a" is found suitable for this optimization, its allocation is replaced by: a = (int *) malloc (dim1 * dim2 *sizeof(int)); and all the references to a[i][j] are replaced by a[i * dim2 + j]. The two main phases of the optimization are the analysis and transformation. The driver of the optimization is matrix_reorg (). Analysis phase: =============== We'll number the dimensions outside-in, meaning the most external is 0, then 1, and so on. The analysis part of the optimization determines K, the escape level of a N-dimensional matrix (K <= N), that allows flattening of the external dimensions 0,1,..., K-1. Escape level 0 means that the whole matrix escapes and no flattening is possible. The analysis part is implemented in analyze_matrix_allocation_site() and analyze_matrix_accesses(). Transformation phase: ===================== In this phase we define the new flattened matrices that replace the original matrices in the code. Implemented in transform_allocation_sites(), transform_access_sites(). Matrix Transposing ================== The idea of Matrix Transposing is organizing the matrix in a different layout such that the dimensions are reordered. This could produce better cache behavior in some cases. For example, lets look at the matrix accesses in the following loop: for (i=0; i<N; i++) for (j=0; j<M; j++) access to a[i][j] This loop can produce good cache behavior because the elements of the inner dimension are accessed sequentially. However, if the accesses of the matrix were of the following form: for (i=0; i<N; i++) for (j=0; j<M; j++) access to a[j][i] In this loop we iterate the columns and not the rows. Therefore, replacing the rows and columns would have had an organization with better (cache) locality. Replacing the dimensions of the matrix is called matrix transposing. This example, of course, could be enhanced to multiple dimensions matrices as well. Since a program could include all kind of accesses, there is a decision mechanism, implemented in analyze_transpose(), which implements a heuristic that tries to determine whether to transpose the matrix or not, according to the form of the more dominant accesses. This decision is transferred to the flattening mechanism, and whether the matrix was transposed or not, the matrix is flattened (if possible). This decision making is based on profiling information and loop information. If profiling information is available, decision making mechanism will be operated, otherwise the matrix will only be flattened (if possible). Both optimizations are described in the paper "Matrix flattening and transposing in GCC" which was presented in GCC summit 2006. http://www.gccsummit.org/2006/2006-GCC-Summit-Proceedings.pdf. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "rtl.h" #include "tree-inline.h" #include "tree-flow.h" #include "tree-flow-inline.h" #include "langhooks.h" #include "hashtab.h" #include "flags.h" #include "ggc.h" #include "debug.h" #include "target.h" #include "cgraph.h" #include "diagnostic-core.h" #include "timevar.h" #include "params.h" #include "fibheap.h" #include "intl.h" #include "function.h" #include "basic-block.h" #include "cfgloop.h" #include "tree-iterator.h" #include "tree-pass.h" #include "opts.h" #include "tree-data-ref.h" #include "tree-chrec.h" #include "tree-scalar-evolution.h" #include "tree-ssa-sccvn.h" /* We need to collect a lot of data from the original malloc, particularly as the gimplifier has converted: orig_var = (struct_type *) malloc (x * sizeof (struct_type *)); into T3 = <constant> ; ** <constant> is amount to malloc; precomputed ** T4 = malloc (T3); T5 = (struct_type *) T4; orig_var = T5; The following struct fields allow us to collect all the necessary data from the gimplified program. The comments in the struct below are all based on the gimple example above. */ struct malloc_call_data { gimple call_stmt; /* Tree for "T4 = malloc (T3);" */ tree size_var; /* Var decl for T3. */ tree malloc_size; /* Tree for "<constant>", the rhs assigned to T3. */ }; static tree can_calculate_expr_before_stmt (tree, sbitmap); static tree can_calculate_stmt_before_stmt (gimple, sbitmap); /* The front end of the compiler, when parsing statements of the form: var = (type_cast) malloc (sizeof (type)); always converts this single statement into the following statements (GIMPLE form): T.1 = sizeof (type); T.2 = malloc (T.1); T.3 = (type_cast) T.2; var = T.3; Since we need to create new malloc statements and modify the original statements somewhat, we need to find all four of the above statements. Currently record_call_1 (called for building cgraph edges) finds and records the statements containing the actual call to malloc, but we need to find the rest of the variables/statements on our own. That is what the following function does. */ static void collect_data_for_malloc_call (gimple stmt, struct malloc_call_data *m_data) { tree size_var = NULL; tree malloc_fn_decl; tree arg1; gcc_assert (is_gimple_call (stmt)); malloc_fn_decl = gimple_call_fndecl (stmt); if (malloc_fn_decl == NULL || DECL_FUNCTION_CODE (malloc_fn_decl) != BUILT_IN_MALLOC) return; arg1 = gimple_call_arg (stmt, 0); size_var = arg1; m_data->call_stmt = stmt; m_data->size_var = size_var; if (TREE_CODE (size_var) != VAR_DECL) m_data->malloc_size = size_var; else m_data->malloc_size = NULL_TREE; } /* Information about matrix access site. For example: if an access site of matrix arr is arr[i][j] the ACCESS_SITE_INFO structure will have the address of arr as its stmt. The INDEX_INFO will hold information about the initial address and index of each dimension. */ struct access_site_info { /* The statement (MEM_REF or POINTER_PLUS_EXPR). */ gimple stmt; /* In case of POINTER_PLUS_EXPR, what is the offset. */ tree offset; /* The index which created the offset. */ tree index; /* The indirection level of this statement. */ int level; /* TRUE for allocation site FALSE for access site. */ bool is_alloc; /* The function containing the access site. */ tree function_decl; /* This access is iterated in the inner most loop */ bool iterated_by_inner_most_loop_p; }; typedef struct access_site_info *access_site_info_p; DEF_VEC_P (access_site_info_p); DEF_VEC_ALLOC_P (access_site_info_p, heap); /* Calls to free when flattening a matrix. */ struct free_info { gimple stmt; tree func; }; /* Information about matrix to flatten. */ struct matrix_info { /* Decl tree of this matrix. */ tree decl; /* Number of dimensions; number of "*" in the type declaration. */ int num_dims; /* Minimum indirection level that escapes, 0 means that the whole matrix escapes, k means that dimensions 0 to ACTUAL_DIM - k escapes. */ int min_indirect_level_escape; gimple min_indirect_level_escape_stmt; /* Hold the allocation site for each level (dimension). We can use NUM_DIMS as the upper bound and allocate the array once with this number of elements and no need to use realloc and MAX_MALLOCED_LEVEL. */ gimple *malloc_for_level; int max_malloced_level; /* Is the matrix transposed. */ bool is_transposed_p; /* The location of the allocation sites (they must be in one function). */ tree allocation_function_decl; /* The calls to free for each level of indirection. */ struct free_info *free_stmts; /* An array which holds for each dimension its size. where dimension 0 is the outer most (one that contains all the others). */ tree *dimension_size; /* An array which holds for each dimension it's original size (before transposing and flattening take place). */ tree *dimension_size_orig; /* An array which holds for each dimension the size of the type of of elements accessed in that level (in bytes). */ HOST_WIDE_INT *dimension_type_size; int dimension_type_size_len; /* An array collecting the count of accesses for each dimension. */ gcov_type *dim_hot_level; /* An array of the accesses to be flattened. elements are of type "struct access_site_info *". */ VEC (access_site_info_p, heap) * access_l; /* A map of how the dimensions will be organized at the end of the analyses. */ int *dim_map; }; /* In each phi node we want to record the indirection level we have when we get to the phi node. Usually we will have phi nodes with more than two arguments, then we must assure that all of them get to the phi node with the same indirection level, otherwise it's not safe to do the flattening. So we record the information regarding the indirection level each time we get to the phi node in this hash table. */ struct matrix_access_phi_node { gimple phi; int indirection_level; }; /* We use this structure to find if the SSA variable is accessed inside the tree and record the tree containing it. */ struct ssa_acc_in_tree { /* The variable whose accesses in the tree we are looking for. */ tree ssa_var; /* The tree and code inside it the ssa_var is accessed, currently it could be an MEM_REF or CALL_EXPR. */ enum tree_code t_code; tree t_tree; /* The place in the containing tree. */ tree *tp; tree second_op; bool var_found; }; static void analyze_matrix_accesses (struct matrix_info *, tree, int, bool, sbitmap, bool); static int transform_allocation_sites (void **, void *); static int transform_access_sites (void **, void *); static int analyze_transpose (void **, void *); static int dump_matrix_reorg_analysis (void **, void *); static bool check_transpose_p; /* Hash function used for the phi nodes. */ static hashval_t mat_acc_phi_hash (const void *p) { const struct matrix_access_phi_node *const ma_phi = (const struct matrix_access_phi_node *) p; return htab_hash_pointer (ma_phi->phi); } /* Equality means phi node pointers are the same. */ static int mat_acc_phi_eq (const void *p1, const void *p2) { const struct matrix_access_phi_node *const phi1 = (const struct matrix_access_phi_node *) p1; const struct matrix_access_phi_node *const phi2 = (const struct matrix_access_phi_node *) p2; if (phi1->phi == phi2->phi) return 1; return 0; } /* Hold the PHI nodes we visit during the traversal for escaping analysis. */ static htab_t htab_mat_acc_phi_nodes = NULL; /* This hash-table holds the information about the matrices we are going to handle. */ static htab_t matrices_to_reorg = NULL; /* Return a hash for MTT, which is really a "matrix_info *". */ static hashval_t mtt_info_hash (const void *mtt) { return htab_hash_pointer (((const struct matrix_info *) mtt)->decl); } /* Return true if MTT1 and MTT2 (which are really both of type "matrix_info *") refer to the same decl. */ static int mtt_info_eq (const void *mtt1, const void *mtt2) { const struct matrix_info *const i1 = (const struct matrix_info *) mtt1; const struct matrix_info *const i2 = (const struct matrix_info *) mtt2; if (i1->decl == i2->decl) return true; return false; } /* Return false if STMT may contain a vector expression. In this situation, all matrices should not be flattened. */ static bool may_flatten_matrices_1 (gimple stmt) { switch (gimple_code (stmt)) { case GIMPLE_ASSIGN: case GIMPLE_CALL: if (!gimple_has_lhs (stmt)) return true; if (TREE_CODE (TREE_TYPE (gimple_get_lhs (stmt))) == VECTOR_TYPE) { if (dump_file) fprintf (dump_file, "Found vector type, don't flatten matrix\n"); return false; } break; case GIMPLE_ASM: /* Asm code could contain vector operations. */ return false; break; default: break; } return true; } /* Return false if there are hand-written vectors in the program. We disable the flattening in such a case. */ static bool may_flatten_matrices (struct cgraph_node *node) { tree decl; struct function *func; basic_block bb; gimple_stmt_iterator gsi; decl = node->decl; if (node->analyzed) { func = DECL_STRUCT_FUNCTION (decl); FOR_EACH_BB_FN (bb, func) for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) if (!may_flatten_matrices_1 (gsi_stmt (gsi))) return false; } return true; } /* Given a VAR_DECL, check its type to determine whether it is a definition of a dynamic allocated matrix and therefore is a suitable candidate for the matrix flattening optimization. Return NULL if VAR_DECL is not such decl. Otherwise, allocate a MATRIX_INFO structure, fill it with the relevant information and return a pointer to it. TODO: handle also statically defined arrays. */ static struct matrix_info * analyze_matrix_decl (tree var_decl) { struct matrix_info *m_node, tmpmi, *mi; tree var_type; int dim_num = 0; gcc_assert (matrices_to_reorg); if (TREE_CODE (var_decl) == PARM_DECL) var_type = DECL_ARG_TYPE (var_decl); else if (TREE_CODE (var_decl) == VAR_DECL) var_type = TREE_TYPE (var_decl); else return NULL; if (!POINTER_TYPE_P (var_type)) return NULL; while (POINTER_TYPE_P (var_type)) { var_type = TREE_TYPE (var_type); dim_num++; } if (dim_num <= 1) return NULL; if (!COMPLETE_TYPE_P (var_type) || TREE_CODE (TYPE_SIZE_UNIT (var_type)) != INTEGER_CST) return NULL; /* Check to see if this pointer is already in there. */ tmpmi.decl = var_decl; mi = (struct matrix_info *) htab_find (matrices_to_reorg, &tmpmi); if (mi) return NULL; /* Record the matrix. */ m_node = (struct matrix_info *) xcalloc (1, sizeof (struct matrix_info)); m_node->decl = var_decl; m_node->num_dims = dim_num; m_node->free_stmts = (struct free_info *) xcalloc (dim_num, sizeof (struct free_info)); /* Init min_indirect_level_escape to -1 to indicate that no escape analysis has been done yet. */ m_node->min_indirect_level_escape = -1; m_node->is_transposed_p = false; return m_node; } /* Free matrix E. */ static void mat_free (void *e) { struct matrix_info *mat = (struct matrix_info *) e; if (!mat) return; free (mat->free_stmts); free (mat->dim_hot_level); free (mat->malloc_for_level); } /* Find all potential matrices. TODO: currently we handle only multidimensional dynamically allocated arrays. */ static void find_matrices_decl (void) { struct matrix_info *tmp; PTR *slot; struct varpool_node *vnode; gcc_assert (matrices_to_reorg); /* For every global variable in the program: Check to see if it's of a candidate type and record it. */ for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed) { tree var_decl = vnode->decl; if (!var_decl || TREE_CODE (var_decl) != VAR_DECL) continue; if (matrices_to_reorg) if ((tmp = analyze_matrix_decl (var_decl))) { if (!TREE_ADDRESSABLE (var_decl)) { slot = htab_find_slot (matrices_to_reorg, tmp, INSERT); *slot = tmp; } } } return; } /* Mark that the matrix MI escapes at level L. */ static void mark_min_matrix_escape_level (struct matrix_info *mi, int l, gimple s) { if (mi->min_indirect_level_escape == -1 || (mi->min_indirect_level_escape > l)) { mi->min_indirect_level_escape = l; mi->min_indirect_level_escape_stmt = s; } } /* Find if the SSA variable is accessed inside the tree and record the tree containing it. The only relevant uses are the case of SSA_NAME, or SSA inside MEM_REF, PLUS_EXPR, POINTER_PLUS_EXPR, MULT_EXPR. */ static void ssa_accessed_in_tree (tree t, struct ssa_acc_in_tree *a) { a->t_code = TREE_CODE (t); switch (a->t_code) { case SSA_NAME: if (t == a->ssa_var) a->var_found = true; break; case MEM_REF: if (SSA_VAR_P (TREE_OPERAND (t, 0)) && TREE_OPERAND (t, 0) == a->ssa_var) a->var_found = true; break; default: break; } } /* Find if the SSA variable is accessed on the right hand side of gimple call STMT. */ static void ssa_accessed_in_call_rhs (gimple stmt, struct ssa_acc_in_tree *a) { tree decl; tree arg; size_t i; a->t_code = CALL_EXPR; for (i = 0; i < gimple_call_num_args (stmt); i++) { arg = gimple_call_arg (stmt, i); if (arg == a->ssa_var) { a->var_found = true; decl = gimple_call_fndecl (stmt); a->t_tree = decl; break; } } } /* Find if the SSA variable is accessed on the right hand side of gimple assign STMT. */ static void ssa_accessed_in_assign_rhs (gimple stmt, struct ssa_acc_in_tree *a) { a->t_code = gimple_assign_rhs_code (stmt); switch (a->t_code) { tree op1, op2; case SSA_NAME: case MEM_REF: CASE_CONVERT: case VIEW_CONVERT_EXPR: ssa_accessed_in_tree (gimple_assign_rhs1 (stmt), a); break; case POINTER_PLUS_EXPR: case PLUS_EXPR: case MULT_EXPR: op1 = gimple_assign_rhs1 (stmt); op2 = gimple_assign_rhs2 (stmt); if (op1 == a->ssa_var) { a->var_found = true; a->second_op = op2; } else if (op2 == a->ssa_var) { a->var_found = true; a->second_op = op1; } break; default: break; } } /* Record the access/allocation site information for matrix MI so we can handle it later in transformation. */ static void record_access_alloc_site_info (struct matrix_info *mi, gimple stmt, tree offset, tree index, int level, bool is_alloc) { struct access_site_info *acc_info; if (!mi->access_l) mi->access_l = VEC_alloc (access_site_info_p, heap, 100); acc_info = (struct access_site_info *) xcalloc (1, sizeof (struct access_site_info)); acc_info->stmt = stmt; acc_info->offset = offset; acc_info->index = index; acc_info->function_decl = current_function_decl; acc_info->level = level; acc_info->is_alloc = is_alloc; VEC_safe_push (access_site_info_p, heap, mi->access_l, acc_info); } /* Record the malloc as the allocation site of the given LEVEL. But first we Make sure that all the size parameters passed to malloc in all the allocation sites could be pre-calculated before the call to the malloc of level 0 (the main malloc call). */ static void add_allocation_site (struct matrix_info *mi, gimple stmt, int level) { struct malloc_call_data mcd; /* Make sure that the allocation sites are in the same function. */ if (!mi->allocation_function_decl) mi->allocation_function_decl = current_function_decl; else if (mi->allocation_function_decl != current_function_decl) { int min_malloc_level; gcc_assert (mi->malloc_for_level); /* Find the minimum malloc level that already has been seen; we known its allocation function must be MI->allocation_function_decl since it's different than CURRENT_FUNCTION_DECL then the escaping level should be MIN (LEVEL, MIN_MALLOC_LEVEL) - 1 , and the allocation function must be set accordingly. */ for (min_malloc_level = 0; min_malloc_level < mi->max_malloced_level && mi->malloc_for_level[min_malloc_level]; min_malloc_level++) ; if (level < min_malloc_level) { mi->allocation_function_decl = current_function_decl; mark_min_matrix_escape_level (mi, min_malloc_level, stmt); } else { mark_min_matrix_escape_level (mi, level, stmt); /* cannot be that (level == min_malloc_level) we would have returned earlier. */ return; } } /* Find the correct malloc information. */ collect_data_for_malloc_call (stmt, &mcd); /* We accept only calls to malloc function; we do not accept calls like calloc and realloc. */ if (!mi->malloc_for_level) { mi->malloc_for_level = XCNEWVEC (gimple, level + 1); mi->max_malloced_level = level + 1; } else if (mi->max_malloced_level <= level) { mi->malloc_for_level = XRESIZEVEC (gimple, mi->malloc_for_level, level + 1); /* Zero the newly allocated items. */ memset (&(mi->malloc_for_level[mi->max_malloced_level + 1]), 0, (level - mi->max_malloced_level) * sizeof (tree)); mi->max_malloced_level = level + 1; } mi->malloc_for_level[level] = stmt; } /* Given an assignment statement STMT that we know that its left-hand-side is the matrix MI variable, we traverse the immediate uses backwards until we get to a malloc site. We make sure that there is one and only one malloc site that sets this variable. When we are performing the flattening we generate a new variable that will hold the size for each dimension; each malloc that allocates a dimension has the size parameter; we use that parameter to initialize the dimension size variable so we can use it later in the address calculations. LEVEL is the dimension we're inspecting. Return if STMT is related to an allocation site. */ static void analyze_matrix_allocation_site (struct matrix_info *mi, gimple stmt, int level, sbitmap visited) { if (gimple_assign_copy_p (stmt) || gimple_assign_cast_p (stmt)) { tree rhs = gimple_assign_rhs1 (stmt); if (TREE_CODE (rhs) == SSA_NAME) { gimple def = SSA_NAME_DEF_STMT (rhs); analyze_matrix_allocation_site (mi, def, level, visited); return; } /* If we are back to the original matrix variable then we are sure that this is analyzed as an access site. */ else if (rhs == mi->decl) return; } /* A result of call to malloc. */ else if (is_gimple_call (stmt)) { int call_flags = gimple_call_flags (stmt); if (!(call_flags & ECF_MALLOC)) { mark_min_matrix_escape_level (mi, level, stmt); return; } else { tree malloc_fn_decl; malloc_fn_decl = gimple_call_fndecl (stmt); if (malloc_fn_decl == NULL_TREE) { mark_min_matrix_escape_level (mi, level, stmt); return; } if (DECL_FUNCTION_CODE (malloc_fn_decl) != BUILT_IN_MALLOC) { if (dump_file) fprintf (dump_file, "Matrix %s is an argument to function %s\n", get_name (mi->decl), get_name (malloc_fn_decl)); mark_min_matrix_escape_level (mi, level, stmt); return; } } /* This is a call to malloc of level 'level'. mi->max_malloced_level-1 == level means that we've seen a malloc statement of level 'level' before. If the statement is not the same one that we've seen before, then there's another malloc statement for the same level, which means that we need to mark it escaping. */ if (mi->malloc_for_level && mi->max_malloced_level-1 == level && mi->malloc_for_level[level] != stmt) { mark_min_matrix_escape_level (mi, level, stmt); return; } else add_allocation_site (mi, stmt, level); return; } /* Looks like we don't know what is happening in this statement so be in the safe side and mark it as escaping. */ mark_min_matrix_escape_level (mi, level, stmt); } /* The transposing decision making. In order to calculate the profitability of transposing, we collect two types of information regarding the accesses: 1. profiling information used to express the hotness of an access, that is how often the matrix is accessed by this access site (count of the access site). 2. which dimension in the access site is iterated by the inner most loop containing this access. The matrix will have a calculated value of weighted hotness for each dimension. Intuitively the hotness level of a dimension is a function of how many times it was the most frequently accessed dimension in the highly executed access sites of this matrix. As computed by following equation: m n __ __ \ \ dim_hot_level[i] += /_ /_ j i acc[j]->dim[i]->iter_by_inner_loop * count(j) Where n is the number of dims and m is the number of the matrix access sites. acc[j]->dim[i]->iter_by_inner_loop is 1 if acc[j] iterates over dim[i] in innermost loop, and is 0 otherwise. The organization of the new matrix should be according to the hotness of each dimension. The hotness of the dimension implies the locality of the elements.*/ static int analyze_transpose (void **slot, void *data ATTRIBUTE_UNUSED) { struct matrix_info *mi = (struct matrix_info *) *slot; int min_escape_l = mi->min_indirect_level_escape; struct loop *loop; affine_iv iv; struct access_site_info *acc_info; int i; if (min_escape_l < 2 || !mi->access_l) { if (mi->access_l) { FOR_EACH_VEC_ELT (access_site_info_p, mi->access_l, i, acc_info) free (acc_info); VEC_free (access_site_info_p, heap, mi->access_l); } return 1; } if (!mi->dim_hot_level) mi->dim_hot_level = (gcov_type *) xcalloc (min_escape_l, sizeof (gcov_type)); for (i = 0; VEC_iterate (access_site_info_p, mi->access_l, i, acc_info); i++) { if (gimple_assign_rhs_code (acc_info->stmt) == POINTER_PLUS_EXPR && acc_info->level < min_escape_l) { loop = loop_containing_stmt (acc_info->stmt); if (!loop || loop->inner) { free (acc_info); continue; } if (simple_iv (loop, loop, acc_info->offset, &iv, true)) { if (iv.step != NULL) { HOST_WIDE_INT istep; istep = int_cst_value (iv.step); if (istep != 0) { acc_info->iterated_by_inner_most_loop_p = 1; mi->dim_hot_level[acc_info->level] += gimple_bb (acc_info->stmt)->count; } } } } free (acc_info); } VEC_free (access_site_info_p, heap, mi->access_l); return 1; } /* Find the index which defines the OFFSET from base. We walk from use to def until we find how the offset was defined. */ static tree get_index_from_offset (tree offset, gimple def_stmt) { tree op1, op2, index; if (gimple_code (def_stmt) == GIMPLE_PHI) return NULL; if ((gimple_assign_copy_p (def_stmt) || gimple_assign_cast_p (def_stmt)) && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME) return get_index_from_offset (offset, SSA_NAME_DEF_STMT (gimple_assign_rhs1 (def_stmt))); else if (is_gimple_assign (def_stmt) && gimple_assign_rhs_code (def_stmt) == MULT_EXPR) { op1 = gimple_assign_rhs1 (def_stmt); op2 = gimple_assign_rhs2 (def_stmt); if (TREE_CODE (op1) != INTEGER_CST && TREE_CODE (op2) != INTEGER_CST) return NULL; index = (TREE_CODE (op1) == INTEGER_CST) ? op2 : op1; return index; } else return NULL_TREE; } /* update MI->dimension_type_size[CURRENT_INDIRECT_LEVEL] with the size of the type related to the SSA_VAR, or the type related to the lhs of STMT, in the case that it is an MEM_REF. */ static void update_type_size (struct matrix_info *mi, gimple stmt, tree ssa_var, int current_indirect_level) { tree lhs; HOST_WIDE_INT type_size; /* Update type according to the type of the MEM_REF expr. */ if (is_gimple_assign (stmt) && TREE_CODE (gimple_assign_lhs (stmt)) == MEM_REF) { lhs = gimple_assign_lhs (stmt); gcc_assert (POINTER_TYPE_P (TREE_TYPE (SSA_NAME_VAR (TREE_OPERAND (lhs, 0))))); type_size = int_size_in_bytes (TREE_TYPE (TREE_TYPE (SSA_NAME_VAR (TREE_OPERAND (lhs, 0))))); } else type_size = int_size_in_bytes (TREE_TYPE (ssa_var)); /* Record the size of elements accessed (as a whole) in the current indirection level (dimension). If the size of elements is not known at compile time, mark it as escaping. */ if (type_size <= 0) mark_min_matrix_escape_level (mi, current_indirect_level, stmt); else { int l = current_indirect_level; if (!mi->dimension_type_size) { mi->dimension_type_size = (HOST_WIDE_INT *) xcalloc (l + 1, sizeof (HOST_WIDE_INT)); mi->dimension_type_size_len = l + 1; } else if (mi->dimension_type_size_len < l + 1) { mi->dimension_type_size = (HOST_WIDE_INT *) xrealloc (mi->dimension_type_size, (l + 1) * sizeof (HOST_WIDE_INT)); memset (&mi->dimension_type_size[mi->dimension_type_size_len], 0, (l + 1 - mi->dimension_type_size_len) * sizeof (HOST_WIDE_INT)); mi->dimension_type_size_len = l + 1; } /* Make sure all the accesses in the same level have the same size of the type. */ if (!mi->dimension_type_size[l]) mi->dimension_type_size[l] = type_size; else if (mi->dimension_type_size[l] != type_size) mark_min_matrix_escape_level (mi, l, stmt); } } /* USE_STMT represents a GIMPLE_CALL, where one of the arguments is the ssa var that we want to check because it came from some use of matrix MI. CURRENT_INDIRECT_LEVEL is the indirection level we reached so far. */ static int analyze_accesses_for_call_stmt (struct matrix_info *mi, tree ssa_var, gimple use_stmt, int current_indirect_level) { tree fndecl = gimple_call_fndecl (use_stmt); if (gimple_call_lhs (use_stmt)) { tree lhs = gimple_call_lhs (use_stmt); struct ssa_acc_in_tree lhs_acc, rhs_acc; memset (&lhs_acc, 0, sizeof (lhs_acc)); memset (&rhs_acc, 0, sizeof (rhs_acc)); lhs_acc.ssa_var = ssa_var; lhs_acc.t_code = ERROR_MARK; ssa_accessed_in_tree (lhs, &lhs_acc); rhs_acc.ssa_var = ssa_var; rhs_acc.t_code = ERROR_MARK; ssa_accessed_in_call_rhs (use_stmt, &rhs_acc); /* The SSA must be either in the left side or in the right side, to understand what is happening. In case the SSA_NAME is found in both sides we should be escaping at this level because in this case we cannot calculate the address correctly. */ if ((lhs_acc.var_found && rhs_acc.var_found && lhs_acc.t_code == MEM_REF) || (!rhs_acc.var_found && !lhs_acc.var_found)) { mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); return current_indirect_level; } gcc_assert (!rhs_acc.var_found || !lhs_acc.var_found); /* If we are storing to the matrix at some level, then mark it as escaping at that level. */ if (lhs_acc.var_found) { int l = current_indirect_level + 1; gcc_assert (lhs_acc.t_code == MEM_REF); mark_min_matrix_escape_level (mi, l, use_stmt); return current_indirect_level; } } if (fndecl) { if (DECL_FUNCTION_CODE (fndecl) != BUILT_IN_FREE) { if (dump_file) fprintf (dump_file, "Matrix %s: Function call %s, level %d escapes.\n", get_name (mi->decl), get_name (fndecl), current_indirect_level); mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); } else if (mi->free_stmts[current_indirect_level].stmt != NULL && mi->free_stmts[current_indirect_level].stmt != use_stmt) mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); else { /*Record the free statements so we can delete them later. */ int l = current_indirect_level; mi->free_stmts[l].stmt = use_stmt; mi->free_stmts[l].func = current_function_decl; } } return current_indirect_level; } /* USE_STMT represents a phi node of the ssa var that we want to check because it came from some use of matrix MI. We check all the escaping levels that get to the PHI node and make sure they are all the same escaping; if not (which is rare) we let the escaping level be the minimum level that gets into that PHI because starting from that level we cannot expect the behavior of the indirections. CURRENT_INDIRECT_LEVEL is the indirection level we reached so far. */ static void analyze_accesses_for_phi_node (struct matrix_info *mi, gimple use_stmt, int current_indirect_level, sbitmap visited, bool record_accesses) { struct matrix_access_phi_node tmp_maphi, *maphi, **pmaphi; tmp_maphi.phi = use_stmt; if ((maphi = (struct matrix_access_phi_node *) htab_find (htab_mat_acc_phi_nodes, &tmp_maphi))) { if (maphi->indirection_level == current_indirect_level) return; else { int level = MIN (maphi->indirection_level, current_indirect_level); size_t j; gimple stmt = NULL; maphi->indirection_level = level; for (j = 0; j < gimple_phi_num_args (use_stmt); j++) { tree def = PHI_ARG_DEF (use_stmt, j); if (gimple_code (SSA_NAME_DEF_STMT (def)) != GIMPLE_PHI) stmt = SSA_NAME_DEF_STMT (def); } mark_min_matrix_escape_level (mi, level, stmt); } return; } maphi = (struct matrix_access_phi_node *) xcalloc (1, sizeof (struct matrix_access_phi_node)); maphi->phi = use_stmt; maphi->indirection_level = current_indirect_level; /* Insert to hash table. */ pmaphi = (struct matrix_access_phi_node **) htab_find_slot (htab_mat_acc_phi_nodes, maphi, INSERT); gcc_assert (pmaphi); *pmaphi = maphi; if (!TEST_BIT (visited, SSA_NAME_VERSION (PHI_RESULT (use_stmt)))) { SET_BIT (visited, SSA_NAME_VERSION (PHI_RESULT (use_stmt))); analyze_matrix_accesses (mi, PHI_RESULT (use_stmt), current_indirect_level, false, visited, record_accesses); RESET_BIT (visited, SSA_NAME_VERSION (PHI_RESULT (use_stmt))); } } /* USE_STMT represents an assign statement (the rhs or lhs include the ssa var that we want to check because it came from some use of matrix MI. CURRENT_INDIRECT_LEVEL is the indirection level we reached so far. */ static int analyze_accesses_for_assign_stmt (struct matrix_info *mi, tree ssa_var, gimple use_stmt, int current_indirect_level, bool last_op, sbitmap visited, bool record_accesses) { tree lhs = gimple_get_lhs (use_stmt); struct ssa_acc_in_tree lhs_acc, rhs_acc; memset (&lhs_acc, 0, sizeof (lhs_acc)); memset (&rhs_acc, 0, sizeof (rhs_acc)); lhs_acc.ssa_var = ssa_var; lhs_acc.t_code = ERROR_MARK; ssa_accessed_in_tree (lhs, &lhs_acc); rhs_acc.ssa_var = ssa_var; rhs_acc.t_code = ERROR_MARK; ssa_accessed_in_assign_rhs (use_stmt, &rhs_acc); /* The SSA must be either in the left side or in the right side, to understand what is happening. In case the SSA_NAME is found in both sides we should be escaping at this level because in this case we cannot calculate the address correctly. */ if ((lhs_acc.var_found && rhs_acc.var_found && lhs_acc.t_code == MEM_REF) || (!rhs_acc.var_found && !lhs_acc.var_found)) { mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); return current_indirect_level; } gcc_assert (!rhs_acc.var_found || !lhs_acc.var_found); /* If we are storing to the matrix at some level, then mark it as escaping at that level. */ if (lhs_acc.var_found) { int l = current_indirect_level + 1; gcc_assert (lhs_acc.t_code == MEM_REF); if (!(gimple_assign_copy_p (use_stmt) || gimple_assign_cast_p (use_stmt)) || (TREE_CODE (gimple_assign_rhs1 (use_stmt)) != SSA_NAME)) mark_min_matrix_escape_level (mi, l, use_stmt); else { gimple def_stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (use_stmt)); analyze_matrix_allocation_site (mi, def_stmt, l, visited); if (record_accesses) record_access_alloc_site_info (mi, use_stmt, NULL_TREE, NULL_TREE, l, true); update_type_size (mi, use_stmt, NULL, l); } return current_indirect_level; } /* Now, check the right-hand-side, to see how the SSA variable is used. */ if (rhs_acc.var_found) { if (rhs_acc.t_code != MEM_REF && rhs_acc.t_code != POINTER_PLUS_EXPR && rhs_acc.t_code != SSA_NAME) { mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); return current_indirect_level; } /* If the access in the RHS has an indirection increase the indirection level. */ if (rhs_acc.t_code == MEM_REF) { if (record_accesses) record_access_alloc_site_info (mi, use_stmt, NULL_TREE, NULL_TREE, current_indirect_level, true); current_indirect_level += 1; } else if (rhs_acc.t_code == POINTER_PLUS_EXPR) { gcc_assert (rhs_acc.second_op); if (last_op) /* Currently we support only one PLUS expression on the SSA_NAME that holds the base address of the current indirection level; to support more general case there is a need to hold a stack of expressions and regenerate the calculation later. */ mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); else { tree index; tree op1, op2; op1 = gimple_assign_rhs1 (use_stmt); op2 = gimple_assign_rhs2 (use_stmt); op2 = (op1 == ssa_var) ? op2 : op1; if (TREE_CODE (op2) == INTEGER_CST) index = build_int_cst (TREE_TYPE (op1), TREE_INT_CST_LOW (op2) / int_size_in_bytes (TREE_TYPE (op1))); else { index = get_index_from_offset (op2, SSA_NAME_DEF_STMT (op2)); if (index == NULL_TREE) { mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); return current_indirect_level; } } if (record_accesses) record_access_alloc_site_info (mi, use_stmt, op2, index, current_indirect_level, false); } } /* If we are storing this level of indirection mark it as escaping. */ if (lhs_acc.t_code == MEM_REF || TREE_CODE (lhs) != SSA_NAME) { int l = current_indirect_level; /* One exception is when we are storing to the matrix variable itself; this is the case of malloc, we must make sure that it's the one and only one call to malloc so we call analyze_matrix_allocation_site to check this out. */ if (TREE_CODE (lhs) != VAR_DECL || lhs != mi->decl) mark_min_matrix_escape_level (mi, current_indirect_level, use_stmt); else { /* Also update the escaping level. */ analyze_matrix_allocation_site (mi, use_stmt, l, visited); if (record_accesses) record_access_alloc_site_info (mi, use_stmt, NULL_TREE, NULL_TREE, l, true); } } else { /* We are placing it in an SSA, follow that SSA. */ analyze_matrix_accesses (mi, lhs, current_indirect_level, rhs_acc.t_code == POINTER_PLUS_EXPR, visited, record_accesses); } } return current_indirect_level; } /* Given a SSA_VAR (coming from a use statement of the matrix MI), follow its uses and level of indirection and find out the minimum indirection level it escapes in (the highest dimension) and the maximum level it is accessed in (this will be the actual dimension of the matrix). The information is accumulated in MI. We look at the immediate uses, if one escapes we finish; if not, we make a recursive call for each one of the immediate uses of the resulting SSA name. */ static void analyze_matrix_accesses (struct matrix_info *mi, tree ssa_var, int current_indirect_level, bool last_op, sbitmap visited, bool record_accesses) { imm_use_iterator imm_iter; use_operand_p use_p; update_type_size (mi, SSA_NAME_DEF_STMT (ssa_var), ssa_var, current_indirect_level); /* We don't go beyond the escaping level when we are performing the flattening. NOTE: we keep the last indirection level that doesn't escape. */ if (mi->min_indirect_level_escape > -1 && mi->min_indirect_level_escape <= current_indirect_level) return; /* Now go over the uses of the SSA_NAME and check how it is used in each one of them. We are mainly looking for the pattern MEM_REF, then a POINTER_PLUS_EXPR, then MEM_REF etc. while in between there could be any number of copies and casts. */ gcc_assert (TREE_CODE (ssa_var) == SSA_NAME); FOR_EACH_IMM_USE_FAST (use_p, imm_iter, ssa_var) { gimple use_stmt = USE_STMT (use_p); if (gimple_code (use_stmt) == GIMPLE_PHI) /* We check all the escaping levels that get to the PHI node and make sure they are all the same escaping; if not (which is rare) we let the escaping level be the minimum level that gets into that PHI because starting from that level we cannot expect the behavior of the indirections. */ analyze_accesses_for_phi_node (mi, use_stmt, current_indirect_level, visited, record_accesses); else if (is_gimple_call (use_stmt)) analyze_accesses_for_call_stmt (mi, ssa_var, use_stmt, current_indirect_level); else if (is_gimple_assign (use_stmt)) current_indirect_level = analyze_accesses_for_assign_stmt (mi, ssa_var, use_stmt, current_indirect_level, last_op, visited, record_accesses); } } typedef struct { tree fn; gimple stmt; } check_var_data; /* A walk_tree function to go over the VAR_DECL, PARM_DECL nodes of the malloc size expression and check that those aren't changed over the function. */ static tree check_var_notmodified_p (tree * tp, int *walk_subtrees, void *data) { basic_block bb; tree t = *tp; check_var_data *callback_data = (check_var_data*) data; tree fn = callback_data->fn; gimple_stmt_iterator gsi; gimple stmt; if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL) return NULL_TREE; FOR_EACH_BB_FN (bb, DECL_STRUCT_FUNCTION (fn)) { for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { stmt = gsi_stmt (gsi); if (!is_gimple_assign (stmt) && !is_gimple_call (stmt)) continue; if (gimple_get_lhs (stmt) == t) { callback_data->stmt = stmt; return t; } } } *walk_subtrees = 1; return NULL_TREE; } /* Go backwards in the use-def chains and find out the expression represented by the possible SSA name in STMT, until it is composed of only VAR_DECL, PARM_DECL and INT_CST. In case of phi nodes we make sure that all the arguments represent the same subexpression, otherwise we fail. */ static tree can_calculate_stmt_before_stmt (gimple stmt, sbitmap visited) { tree op1, op2, res; enum tree_code code; switch (gimple_code (stmt)) { case GIMPLE_ASSIGN: code = gimple_assign_rhs_code (stmt); op1 = gimple_assign_rhs1 (stmt); switch (code) { case POINTER_PLUS_EXPR: case PLUS_EXPR: case MINUS_EXPR: case MULT_EXPR: op2 = gimple_assign_rhs2 (stmt); op1 = can_calculate_expr_before_stmt (op1, visited); if (!op1) return NULL_TREE; op2 = can_calculate_expr_before_stmt (op2, visited); if (op2) return fold_build2 (code, gimple_expr_type (stmt), op1, op2); return NULL_TREE; CASE_CONVERT: res = can_calculate_expr_before_stmt (op1, visited); if (res != NULL_TREE) return build1 (code, gimple_expr_type (stmt), res); else return NULL_TREE; default: if (gimple_assign_single_p (stmt)) return can_calculate_expr_before_stmt (op1, visited); else return NULL_TREE; } case GIMPLE_PHI: { size_t j; res = NULL_TREE; /* Make sure all the arguments represent the same value. */ for (j = 0; j < gimple_phi_num_args (stmt); j++) { tree new_res; tree def = PHI_ARG_DEF (stmt, j); new_res = can_calculate_expr_before_stmt (def, visited); if (res == NULL_TREE) res = new_res; else if (!new_res || !expressions_equal_p (res, new_res)) return NULL_TREE; } return res; } default: return NULL_TREE; } } /* Go backwards in the use-def chains and find out the expression represented by the possible SSA name in EXPR, until it is composed of only VAR_DECL, PARM_DECL and INT_CST. In case of phi nodes we make sure that all the arguments represent the same subexpression, otherwise we fail. */ static tree can_calculate_expr_before_stmt (tree expr, sbitmap visited) { gimple def_stmt; tree res; switch (TREE_CODE (expr)) { case SSA_NAME: /* Case of loop, we don't know to represent this expression. */ if (TEST_BIT (visited, SSA_NAME_VERSION (expr))) return NULL_TREE; SET_BIT (visited, SSA_NAME_VERSION (expr)); def_stmt = SSA_NAME_DEF_STMT (expr); res = can_calculate_stmt_before_stmt (def_stmt, visited); RESET_BIT (visited, SSA_NAME_VERSION (expr)); return res; case VAR_DECL: case PARM_DECL: case INTEGER_CST: return expr; default: return NULL_TREE; } } /* There should be only one allocation function for the dimensions that don't escape. Here we check the allocation sites in this function. We must make sure that all the dimensions are allocated using malloc and that the malloc size parameter expression could be pre-calculated before the call to the malloc of dimension 0. Given a candidate matrix for flattening -- MI -- check if it's appropriate for flattening -- we analyze the allocation sites that we recorded in the previous analysis. The result of the analysis is a level of indirection (matrix dimension) in which the flattening is safe. We check the following conditions: 1. There is only one allocation site for each dimension. 2. The allocation sites of all the dimensions are in the same function. (The above two are being taken care of during the analysis when we check the allocation site). 3. All the dimensions that we flatten are allocated at once; thus the total size must be known before the allocation of the dimension 0 (top level) -- we must make sure we represent the size of the allocation as an expression of global parameters or constants and that those doesn't change over the function. */ static int check_allocation_function (void **slot, void *data ATTRIBUTE_UNUSED) { int level; struct matrix_info *mi = (struct matrix_info *) *slot; sbitmap visited; if (!mi->malloc_for_level) return 1; visited = sbitmap_alloc (num_ssa_names); /* Do nothing if the current function is not the allocation function of MI. */ if (mi->allocation_function_decl != current_function_decl /* We aren't in the main allocation function yet. */ || !mi->malloc_for_level[0]) return 1; for (level = 1; level < mi->max_malloced_level; level++) if (!mi->malloc_for_level[level]) break; mark_min_matrix_escape_level (mi, level, NULL); /* Check if the expression of the size passed to malloc could be pre-calculated before the malloc of level 0. */ for (level = 1; level < mi->min_indirect_level_escape; level++) { gimple call_stmt; tree size; struct malloc_call_data mcd = {NULL, NULL_TREE, NULL_TREE}; call_stmt = mi->malloc_for_level[level]; /* Find the correct malloc information. */ collect_data_for_malloc_call (call_stmt, &mcd); /* No need to check anticipation for constants. */ if (TREE_CODE (mcd.size_var) == INTEGER_CST) { if (!mi->dimension_size) { mi->dimension_size = (tree *) xcalloc (mi->min_indirect_level_escape, sizeof (tree)); mi->dimension_size_orig = (tree *) xcalloc (mi->min_indirect_level_escape, sizeof (tree)); } mi->dimension_size[level] = mcd.size_var; mi->dimension_size_orig[level] = mcd.size_var; continue; } /* ??? Here we should also add the way to calculate the size expression not only know that it is anticipated. */ sbitmap_zero (visited); size = can_calculate_expr_before_stmt (mcd.size_var, visited); if (size == NULL_TREE) { mark_min_matrix_escape_level (mi, level, call_stmt); if (dump_file) fprintf (dump_file, "Matrix %s: Cannot calculate the size of allocation, escaping at level %d\n", get_name (mi->decl), level); break; } if (!mi->dimension_size) { mi->dimension_size = (tree *) xcalloc (mi->min_indirect_level_escape, sizeof (tree)); mi->dimension_size_orig = (tree *) xcalloc (mi->min_indirect_level_escape, sizeof (tree)); } mi->dimension_size[level] = size; mi->dimension_size_orig[level] = size; } /* We don't need those anymore. */ for (level = mi->min_indirect_level_escape; level < mi->max_malloced_level; level++) mi->malloc_for_level[level] = NULL; return 1; } /* Track all access and allocation sites. */ static void find_sites_in_func (bool record) { sbitmap visited_stmts_1; gimple_stmt_iterator gsi; gimple stmt; basic_block bb; struct matrix_info tmpmi, *mi; visited_stmts_1 = sbitmap_alloc (num_ssa_names); FOR_EACH_BB (bb) { for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { tree lhs; stmt = gsi_stmt (gsi); lhs = gimple_get_lhs (stmt); if (lhs != NULL_TREE && TREE_CODE (lhs) == VAR_DECL) { tmpmi.decl = lhs; if ((mi = (struct matrix_info *) htab_find (matrices_to_reorg, &tmpmi))) { sbitmap_zero (visited_stmts_1); analyze_matrix_allocation_site (mi, stmt, 0, visited_stmts_1); } } if (is_gimple_assign (stmt) && gimple_assign_single_p (stmt) && TREE_CODE (lhs) == SSA_NAME && TREE_CODE (gimple_assign_rhs1 (stmt)) == VAR_DECL) { tmpmi.decl = gimple_assign_rhs1 (stmt); if ((mi = (struct matrix_info *) htab_find (matrices_to_reorg, &tmpmi))) { sbitmap_zero (visited_stmts_1); analyze_matrix_accesses (mi, lhs, 0, false, visited_stmts_1, record); } } } } sbitmap_free (visited_stmts_1); } /* Traverse the use-def chains to see if there are matrices that are passed through pointers and we cannot know how they are accessed. For each SSA-name defined by a global variable of our interest, we traverse the use-def chains of the SSA and follow the indirections, and record in what level of indirection the use of the variable escapes. A use of a pointer escapes when it is passed to a function, stored into memory or assigned (except in malloc and free calls). */ static void record_all_accesses_in_func (void) { unsigned i; sbitmap visited_stmts_1; visited_stmts_1 = sbitmap_alloc (num_ssa_names); for (i = 0; i < num_ssa_names; i++) { struct matrix_info tmpmi, *mi; tree ssa_var = ssa_name (i); tree rhs, lhs; if (!ssa_var || !is_gimple_assign (SSA_NAME_DEF_STMT (ssa_var)) || !gimple_assign_single_p (SSA_NAME_DEF_STMT (ssa_var))) continue; rhs = gimple_assign_rhs1 (SSA_NAME_DEF_STMT (ssa_var)); lhs = gimple_assign_lhs (SSA_NAME_DEF_STMT (ssa_var)); if (TREE_CODE (rhs) != VAR_DECL && TREE_CODE (lhs) != VAR_DECL) continue; /* If the RHS is a matrix that we want to analyze, follow the def-use chain for this SSA_VAR and check for escapes or apply the flattening. */ tmpmi.decl = rhs; if ((mi = (struct matrix_info *) htab_find (matrices_to_reorg, &tmpmi))) { /* This variable will track the visited PHI nodes, so we can limit its size to the maximum number of SSA names. */ sbitmap_zero (visited_stmts_1); analyze_matrix_accesses (mi, ssa_var, 0, false, visited_stmts_1, true); } } sbitmap_free (visited_stmts_1); } /* Used when we want to convert the expression: RESULT = something * ORIG to RESULT = something * NEW_VAL. If ORIG and NEW_VAL are power of 2, shift operations can be done, else division and multiplication. */ static tree compute_offset (HOST_WIDE_INT orig, HOST_WIDE_INT new_val, tree result) { int x, y; tree result1, ratio, log, orig_tree, new_tree; x = exact_log2 (orig); y = exact_log2 (new_val); if (x != -1 && y != -1) { if (x == y) return result; else if (x > y) { log = build_int_cst (TREE_TYPE (result), x - y); result1 = fold_build2 (LSHIFT_EXPR, TREE_TYPE (result), result, log); return result1; } log = build_int_cst (TREE_TYPE (result), y - x); result1 = fold_build2 (RSHIFT_EXPR, TREE_TYPE (result), result, log); return result1; } orig_tree = build_int_cst (TREE_TYPE (result), orig); new_tree = build_int_cst (TREE_TYPE (result), new_val); ratio = fold_build2 (TRUNC_DIV_EXPR, TREE_TYPE (result), result, orig_tree); result1 = fold_build2 (MULT_EXPR, TREE_TYPE (result), ratio, new_tree); return result1; } /* We know that we are allowed to perform matrix flattening (according to the escape analysis), so we traverse the use-def chains of the SSA vars defined by the global variables pointing to the matrices of our interest. in each use of the SSA we calculate the offset from the base address according to the following equation: a[I1][I2]...[Ik] , where D1..Dk is the length of each dimension and the escaping level is m <= k, and a' is the new allocated matrix, will be translated to : b[I(m+1)]...[Ik] where b = a' + I1*D2...*Dm + I2*D3...Dm + ... + Im */ static int transform_access_sites (void **slot, void *data ATTRIBUTE_UNUSED) { gimple_stmt_iterator gsi; struct matrix_info *mi = (struct matrix_info *) *slot; int min_escape_l = mi->min_indirect_level_escape; struct access_site_info *acc_info; enum tree_code code; int i; if (min_escape_l < 2 || !mi->access_l) return 1; for (i = 0; VEC_iterate (access_site_info_p, mi->access_l, i, acc_info); i++) { /* This is possible because we collect the access sites before we determine the final minimum indirection level. */ if (acc_info->level >= min_escape_l) { free (acc_info); continue; } if (acc_info->is_alloc) { if (acc_info->level >= 0 && gimple_bb (acc_info->stmt)) { ssa_op_iter iter; tree def; gimple stmt = acc_info->stmt; tree lhs; FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) mark_sym_for_renaming (SSA_NAME_VAR (def)); gsi = gsi_for_stmt (stmt); gcc_assert (is_gimple_assign (acc_info->stmt)); lhs = gimple_assign_lhs (acc_info->stmt); if (TREE_CODE (lhs) == SSA_NAME && acc_info->level < min_escape_l - 1) { imm_use_iterator imm_iter; use_operand_p use_p; gimple use_stmt; FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, lhs) FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) { tree rhs, tmp; gimple new_stmt; gcc_assert (gimple_assign_rhs_code (acc_info->stmt) == MEM_REF); /* Emit convert statement to convert to type of use. */ tmp = create_tmp_var (TREE_TYPE (lhs), "new"); add_referenced_var (tmp); rhs = gimple_assign_rhs1 (acc_info->stmt); rhs = fold_convert (TREE_TYPE (tmp), TREE_OPERAND (rhs, 0)); new_stmt = gimple_build_assign (tmp, rhs); tmp = make_ssa_name (tmp, new_stmt); gimple_assign_set_lhs (new_stmt, tmp); gsi = gsi_for_stmt (acc_info->stmt); gsi_insert_after (&gsi, new_stmt, GSI_SAME_STMT); SET_USE (use_p, tmp); } } if (acc_info->level < min_escape_l - 1) gsi_remove (&gsi, true); } free (acc_info); continue; } code = gimple_assign_rhs_code (acc_info->stmt); if (code == MEM_REF && acc_info->level < min_escape_l - 1) { /* Replace the MEM_REF with NOP (cast) usually we are casting from "pointer to type" to "type". */ tree t = build1 (NOP_EXPR, TREE_TYPE (gimple_assign_rhs1 (acc_info->stmt)), TREE_OPERAND (gimple_assign_rhs1 (acc_info->stmt), 0)); gimple_assign_set_rhs_code (acc_info->stmt, NOP_EXPR); gimple_assign_set_rhs1 (acc_info->stmt, t); } else if (code == POINTER_PLUS_EXPR && acc_info->level < (min_escape_l)) { imm_use_iterator imm_iter; use_operand_p use_p; tree offset; int k = acc_info->level; tree num_elements, total_elements; tree tmp1; tree d_size = mi->dimension_size[k]; /* We already make sure in the analysis that the first operand is the base and the second is the offset. */ offset = acc_info->offset; if (mi->dim_map[k] == min_escape_l - 1) { if (!check_transpose_p || mi->is_transposed_p == false) tmp1 = offset; else { tree new_offset; new_offset = compute_offset (mi->dimension_type_size[min_escape_l], mi->dimension_type_size[k + 1], offset); total_elements = new_offset; if (new_offset != offset) { gsi = gsi_for_stmt (acc_info->stmt); tmp1 = force_gimple_operand_gsi (&gsi, total_elements, true, NULL, true, GSI_SAME_STMT); } else tmp1 = offset; } } else { d_size = mi->dimension_size[mi->dim_map[k] + 1]; num_elements = fold_build2 (MULT_EXPR, sizetype, fold_convert (sizetype, acc_info->index), fold_convert (sizetype, d_size)); add_referenced_var (d_size); gsi = gsi_for_stmt (acc_info->stmt); tmp1 = force_gimple_operand_gsi (&gsi, num_elements, true, NULL, true, GSI_SAME_STMT); } /* Replace the offset if needed. */ if (tmp1 != offset) { if (TREE_CODE (offset) == SSA_NAME) { gimple use_stmt; FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, offset) FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) if (use_stmt == acc_info->stmt) SET_USE (use_p, tmp1); } else { gcc_assert (TREE_CODE (offset) == INTEGER_CST); gimple_assign_set_rhs2 (acc_info->stmt, tmp1); update_stmt (acc_info->stmt); } } } /* ??? meanwhile this happens because we record the same access site more than once; we should be using a hash table to avoid this and insert the STMT of the access site only once. else gcc_unreachable (); */ free (acc_info); } VEC_free (access_site_info_p, heap, mi->access_l); update_ssa (TODO_update_ssa); #ifdef ENABLE_CHECKING verify_ssa (true); #endif return 1; } /* Sort A array of counts. Arrange DIM_MAP to reflect the new order. */ static void sort_dim_hot_level (gcov_type * a, int *dim_map, int n) { int i, j, tmp1; gcov_type tmp; for (i = 0; i < n - 1; i++) { for (j = 0; j < n - 1 - i; j++) { if (a[j + 1] < a[j]) { tmp = a[j]; /* swap a[j] and a[j+1] */ a[j] = a[j + 1]; a[j + 1] = tmp; tmp1 = dim_map[j]; dim_map[j] = dim_map[j + 1]; dim_map[j + 1] = tmp1; } } } } /* Replace multiple mallocs (one for each dimension) to one malloc with the size of DIM1*DIM2*...*DIMN*size_of_element Make sure that we hold the size in the malloc site inside a new global variable; this way we ensure that the size doesn't change and it is accessible from all the other functions that uses the matrix. Also, the original calls to free are deleted, and replaced by a new call to free the flattened matrix. */ static int transform_allocation_sites (void **slot, void *data ATTRIBUTE_UNUSED) { int i; struct matrix_info *mi; tree type, oldfn, prev_dim_size; gimple call_stmt_0, use_stmt; struct cgraph_node *c_node; struct cgraph_edge *e; gimple_stmt_iterator gsi; struct malloc_call_data mcd = {NULL, NULL_TREE, NULL_TREE}; HOST_WIDE_INT element_size; imm_use_iterator imm_iter; use_operand_p use_p; tree old_size_0, tmp; int min_escape_l; int id; mi = (struct matrix_info *) *slot; min_escape_l = mi->min_indirect_level_escape; if (!mi->malloc_for_level) mi->min_indirect_level_escape = 0; if (mi->min_indirect_level_escape < 2) return 1; mi->dim_map = (int *) xcalloc (mi->min_indirect_level_escape, sizeof (int)); for (i = 0; i < mi->min_indirect_level_escape; i++) mi->dim_map[i] = i; if (check_transpose_p) { int i; if (dump_file) { fprintf (dump_file, "Matrix %s:\n", get_name (mi->decl)); for (i = 0; i < min_escape_l; i++) { fprintf (dump_file, "dim %d before sort ", i); if (mi->dim_hot_level) fprintf (dump_file, "count is " HOST_WIDEST_INT_PRINT_DEC " \n", mi->dim_hot_level[i]); } } sort_dim_hot_level (mi->dim_hot_level, mi->dim_map, mi->min_indirect_level_escape); if (dump_file) for (i = 0; i < min_escape_l; i++) { fprintf (dump_file, "dim %d after sort\n", i); if (mi->dim_hot_level) fprintf (dump_file, "count is " HOST_WIDE_INT_PRINT_DEC " \n", (HOST_WIDE_INT) mi->dim_hot_level[i]); } for (i = 0; i < mi->min_indirect_level_escape; i++) { if (dump_file) fprintf (dump_file, "dim_map[%d] after sort %d\n", i, mi->dim_map[i]); if (mi->dim_map[i] != i) { if (dump_file) fprintf (dump_file, "Transposed dimensions: dim %d is now dim %d\n", mi->dim_map[i], i); mi->is_transposed_p = true; } } } else { for (i = 0; i < mi->min_indirect_level_escape; i++) mi->dim_map[i] = i; } /* Call statement of allocation site of level 0. */ call_stmt_0 = mi->malloc_for_level[0]; /* Finds the correct malloc information. */ collect_data_for_malloc_call (call_stmt_0, &mcd); mi->dimension_size[0] = mcd.size_var; mi->dimension_size_orig[0] = mcd.size_var; /* Make sure that the variables in the size expression for all the dimensions (above level 0) aren't modified in the allocation function. */ for (i = 1; i < mi->min_indirect_level_escape; i++) { tree t; check_var_data data; /* mi->dimension_size must contain the expression of the size calculated in check_allocation_function. */ gcc_assert (mi->dimension_size[i]); data.fn = mi->allocation_function_decl; data.stmt = NULL; t = walk_tree_without_duplicates (&(mi->dimension_size[i]), check_var_notmodified_p, &data); if (t != NULL_TREE) { mark_min_matrix_escape_level (mi, i, data.stmt); break; } } if (mi->min_indirect_level_escape < 2) return 1; /* Since we should make sure that the size expression is available before the call to malloc of level 0. */ gsi = gsi_for_stmt (call_stmt_0); /* Find out the size of each dimension by looking at the malloc sites and create a global variable to hold it. We add the assignment to the global before the malloc of level 0. */ /* To be able to produce gimple temporaries. */ oldfn = current_function_decl; current_function_decl = mi->allocation_function_decl; push_cfun (DECL_STRUCT_FUNCTION (mi->allocation_function_decl)); /* Set the dimension sizes as follows: DIM_SIZE[i] = DIM_SIZE[n] * ... * DIM_SIZE[i] where n is the maximum non escaping level. */ element_size = mi->dimension_type_size[mi->min_indirect_level_escape]; prev_dim_size = NULL_TREE; for (i = mi->min_indirect_level_escape - 1; i >= 0; i--) { tree dim_size, dim_var; gimple stmt; tree d_type_size; /* Now put the size expression in a global variable and initialize it to the size expression before the malloc of level 0. */ dim_var = add_new_static_var (TREE_TYPE (mi->dimension_size_orig[mi->dim_map[i]])); type = TREE_TYPE (mi->dimension_size_orig[mi->dim_map[i]]); /* DIM_SIZE = MALLOC_SIZE_PARAM / TYPE_SIZE. */ /* Find which dim ID becomes dim I. */ for (id = 0; id < mi->min_indirect_level_escape; id++) if (mi->dim_map[id] == i) break; d_type_size = build_int_cst (type, mi->dimension_type_size[id + 1]); if (!prev_dim_size) prev_dim_size = build_int_cst (type, element_size); if (!check_transpose_p && i == mi->min_indirect_level_escape - 1) { dim_size = mi->dimension_size_orig[id]; } else { dim_size = fold_build2 (TRUNC_DIV_EXPR, type, mi->dimension_size_orig[id], d_type_size); dim_size = fold_build2 (MULT_EXPR, type, dim_size, prev_dim_size); } dim_size = force_gimple_operand_gsi (&gsi, dim_size, true, NULL, true, GSI_SAME_STMT); /* GLOBAL_HOLDING_THE_SIZE = DIM_SIZE. */ stmt = gimple_build_assign (dim_var, dim_size); mark_symbols_for_renaming (stmt); gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); prev_dim_size = mi->dimension_size[i] = dim_var; } update_ssa (TODO_update_ssa); /* Replace the malloc size argument in the malloc of level 0 to be the size of all the dimensions. */ c_node = cgraph_get_node (mi->allocation_function_decl); gcc_checking_assert (c_node); old_size_0 = gimple_call_arg (call_stmt_0, 0); tmp = force_gimple_operand_gsi (&gsi, mi->dimension_size[0], true, NULL, true, GSI_SAME_STMT); if (TREE_CODE (old_size_0) == SSA_NAME) { FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, old_size_0) FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) if (use_stmt == call_stmt_0) SET_USE (use_p, tmp); } /* When deleting the calls to malloc we need also to remove the edge from the call graph to keep it consistent. Notice that cgraph_edge may create a new node in the call graph if there is no node for the given declaration; this shouldn't be the case but currently there is no way to check this outside of "cgraph.c". */ for (i = 1; i < mi->min_indirect_level_escape; i++) { gimple_stmt_iterator gsi; gimple call_stmt = mi->malloc_for_level[i]; gcc_assert (is_gimple_call (call_stmt)); e = cgraph_edge (c_node, call_stmt); gcc_assert (e); cgraph_remove_edge (e); gsi = gsi_for_stmt (call_stmt); /* Remove the call stmt. */ gsi_remove (&gsi, true); /* Remove the assignment of the allocated area. */ FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, gimple_call_lhs (call_stmt)) { gsi = gsi_for_stmt (use_stmt); gsi_remove (&gsi, true); } } update_ssa (TODO_update_ssa); #ifdef ENABLE_CHECKING verify_ssa (true); #endif /* Delete the calls to free. */ for (i = 1; i < mi->min_indirect_level_escape; i++) { gimple_stmt_iterator gsi; /* ??? wonder why this case is possible but we failed on it once. */ if (!mi->free_stmts[i].stmt) continue; c_node = cgraph_get_node (mi->free_stmts[i].func); gcc_checking_assert (c_node); gcc_assert (is_gimple_call (mi->free_stmts[i].stmt)); e = cgraph_edge (c_node, mi->free_stmts[i].stmt); gcc_assert (e); cgraph_remove_edge (e); current_function_decl = mi->free_stmts[i].func; set_cfun (DECL_STRUCT_FUNCTION (mi->free_stmts[i].func)); gsi = gsi_for_stmt (mi->free_stmts[i].stmt); gsi_remove (&gsi, true); } /* Return to the previous situation. */ current_function_decl = oldfn; pop_cfun (); return 1; } /* Print out the results of the escape analysis. */ static int dump_matrix_reorg_analysis (void **slot, void *data ATTRIBUTE_UNUSED) { struct matrix_info *mi = (struct matrix_info *) *slot; if (!dump_file) return 1; fprintf (dump_file, "Matrix \"%s\"; Escaping Level: %d, Num Dims: %d,", get_name (mi->decl), mi->min_indirect_level_escape, mi->num_dims); fprintf (dump_file, " Malloc Dims: %d, ", mi->max_malloced_level); fprintf (dump_file, "\n"); if (mi->min_indirect_level_escape >= 2) fprintf (dump_file, "Flattened %d dimensions \n", mi->min_indirect_level_escape); return 1; } /* Perform matrix flattening. */ static unsigned int matrix_reorg (void) { struct cgraph_node *node; if (profile_info) check_transpose_p = true; else check_transpose_p = false; /* If there are hand written vectors, we skip this optimization. */ for (node = cgraph_nodes; node; node = node->next) if (!may_flatten_matrices (node)) return 0; matrices_to_reorg = htab_create (37, mtt_info_hash, mtt_info_eq, mat_free); /* Find and record all potential matrices in the program. */ find_matrices_decl (); /* Analyze the accesses of the matrices (escaping analysis). */ for (node = cgraph_nodes; node; node = node->next) if (node->analyzed) { tree temp_fn; temp_fn = current_function_decl; current_function_decl = node->decl; push_cfun (DECL_STRUCT_FUNCTION (node->decl)); bitmap_obstack_initialize (NULL); gimple_register_cfg_hooks (); if (!gimple_in_ssa_p (cfun)) { free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); pop_cfun (); current_function_decl = temp_fn; bitmap_obstack_release (NULL); return 0; } #ifdef ENABLE_CHECKING verify_flow_info (); #endif if (!matrices_to_reorg) { free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); pop_cfun (); current_function_decl = temp_fn; bitmap_obstack_release (NULL); return 0; } /* Create htap for phi nodes. */ htab_mat_acc_phi_nodes = htab_create (37, mat_acc_phi_hash, mat_acc_phi_eq, free); if (!check_transpose_p) find_sites_in_func (false); else { find_sites_in_func (true); loop_optimizer_init (LOOPS_NORMAL); if (current_loops) scev_initialize (); htab_traverse (matrices_to_reorg, analyze_transpose, NULL); if (current_loops) { scev_finalize (); loop_optimizer_finalize (); current_loops = NULL; } } /* If the current function is the allocation function for any of the matrices we check its allocation and the escaping level. */ htab_traverse (matrices_to_reorg, check_allocation_function, NULL); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); pop_cfun (); current_function_decl = temp_fn; bitmap_obstack_release (NULL); } htab_traverse (matrices_to_reorg, transform_allocation_sites, NULL); /* Now transform the accesses. */ for (node = cgraph_nodes; node; node = node->next) if (node->analyzed) { /* Remember that allocation sites have been handled. */ tree temp_fn; temp_fn = current_function_decl; current_function_decl = node->decl; push_cfun (DECL_STRUCT_FUNCTION (node->decl)); bitmap_obstack_initialize (NULL); gimple_register_cfg_hooks (); record_all_accesses_in_func (); htab_traverse (matrices_to_reorg, transform_access_sites, NULL); cgraph_rebuild_references (); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); pop_cfun (); current_function_decl = temp_fn; bitmap_obstack_release (NULL); } htab_traverse (matrices_to_reorg, dump_matrix_reorg_analysis, NULL); current_function_decl = NULL; set_cfun (NULL); matrices_to_reorg = NULL; return 0; } /* The condition for matrix flattening to be performed. */ static bool gate_matrix_reorg (void) { return flag_ipa_matrix_reorg && flag_whole_program; } struct simple_ipa_opt_pass pass_ipa_matrix_reorg = { { SIMPLE_IPA_PASS, "matrix-reorg", /* name */ gate_matrix_reorg, /* gate */ matrix_reorg, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_NONE, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_dump_cgraph /* todo_flags_finish */ } };
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