| /* Loop distribution. |
| Copyright (C) 2006-2018 Free Software Foundation, Inc. |
| Contributed by Georges-Andre Silber <Georges-Andre.Silber@ensmp.fr> |
| and Sebastian Pop <sebastian.pop@amd.com>. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by the |
| Free Software Foundation; either version 3, or (at your option) any |
| later version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This pass performs loop distribution: for example, the loop |
| |
| |DO I = 2, N |
| | A(I) = B(I) + C |
| | D(I) = A(I-1)*E |
| |ENDDO |
| |
| is transformed to |
| |
| |DOALL I = 2, N |
| | A(I) = B(I) + C |
| |ENDDO |
| | |
| |DOALL I = 2, N |
| | D(I) = A(I-1)*E |
| |ENDDO |
| |
| Loop distribution is the dual of loop fusion. It separates statements |
| of a loop (or loop nest) into multiple loops (or loop nests) with the |
| same loop header. The major goal is to separate statements which may |
| be vectorized from those that can't. This pass implements distribution |
| in the following steps: |
| |
| 1) Seed partitions with specific type statements. For now we support |
| two types seed statements: statement defining variable used outside |
| of loop; statement storing to memory. |
| 2) Build reduced dependence graph (RDG) for loop to be distributed. |
| The vertices (RDG:V) model all statements in the loop and the edges |
| (RDG:E) model flow and control dependencies between statements. |
| 3) Apart from RDG, compute data dependencies between memory references. |
| 4) Starting from seed statement, build up partition by adding depended |
| statements according to RDG's dependence information. Partition is |
| classified as parallel type if it can be executed paralleled; or as |
| sequential type if it can't. Parallel type partition is further |
| classified as different builtin kinds if it can be implemented as |
| builtin function calls. |
| 5) Build partition dependence graph (PG) based on data dependencies. |
| The vertices (PG:V) model all partitions and the edges (PG:E) model |
| all data dependencies between every partitions pair. In general, |
| data dependence is either compilation time known or unknown. In C |
| family languages, there exists quite amount compilation time unknown |
| dependencies because of possible alias relation of data references. |
| We categorize PG's edge to two types: "true" edge that represents |
| compilation time known data dependencies; "alias" edge for all other |
| data dependencies. |
| 6) Traverse subgraph of PG as if all "alias" edges don't exist. Merge |
| partitions in each strong connected component (SCC) correspondingly. |
| Build new PG for merged partitions. |
| 7) Traverse PG again and this time with both "true" and "alias" edges |
| included. We try to break SCCs by removing some edges. Because |
| SCCs by "true" edges are all fused in step 6), we can break SCCs |
| by removing some "alias" edges. It's NP-hard to choose optimal |
| edge set, fortunately simple approximation is good enough for us |
| given the small problem scale. |
| 8) Collect all data dependencies of the removed "alias" edges. Create |
| runtime alias checks for collected data dependencies. |
| 9) Version loop under the condition of runtime alias checks. Given |
| loop distribution generally introduces additional overhead, it is |
| only useful if vectorization is achieved in distributed loop. We |
| version loop with internal function call IFN_LOOP_DIST_ALIAS. If |
| no distributed loop can be vectorized, we simply remove distributed |
| loops and recover to the original one. |
| |
| TODO: |
| 1) We only distribute innermost two-level loop nest now. We should |
| extend it for arbitrary loop nests in the future. |
| 2) We only fuse partitions in SCC now. A better fusion algorithm is |
| desired to minimize loop overhead, maximize parallelism and maximize |
| data reuse. */ |
| |
| #include "config.h" |
| #define INCLUDE_ALGORITHM /* stable_sort */ |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "cfghooks.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "gimple-pretty-print.h" |
| #include "fold-const.h" |
| #include "cfganal.h" |
| #include "gimple-iterator.h" |
| #include "gimplify-me.h" |
| #include "stor-layout.h" |
| #include "tree-cfg.h" |
| #include "tree-ssa-loop-manip.h" |
| #include "tree-ssa-loop-ivopts.h" |
| #include "tree-ssa-loop.h" |
| #include "tree-into-ssa.h" |
| #include "tree-ssa.h" |
| #include "cfgloop.h" |
| #include "tree-scalar-evolution.h" |
| #include "params.h" |
| #include "tree-vectorizer.h" |
| |
| |
| #define MAX_DATAREFS_NUM \ |
| ((unsigned) PARAM_VALUE (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS)) |
| |
| /* Threshold controlling number of distributed partitions. Given it may |
| be unnecessary if a memory stream cost model is invented in the future, |
| we define it as a temporary macro, rather than a parameter. */ |
| #define NUM_PARTITION_THRESHOLD (4) |
| |
| /* Hashtable helpers. */ |
| |
| struct ddr_hasher : nofree_ptr_hash <struct data_dependence_relation> |
| { |
| static inline hashval_t hash (const data_dependence_relation *); |
| static inline bool equal (const data_dependence_relation *, |
| const data_dependence_relation *); |
| }; |
| |
| /* Hash function for data dependence. */ |
| |
| inline hashval_t |
| ddr_hasher::hash (const data_dependence_relation *ddr) |
| { |
| inchash::hash h; |
| h.add_ptr (DDR_A (ddr)); |
| h.add_ptr (DDR_B (ddr)); |
| return h.end (); |
| } |
| |
| /* Hash table equality function for data dependence. */ |
| |
| inline bool |
| ddr_hasher::equal (const data_dependence_relation *ddr1, |
| const data_dependence_relation *ddr2) |
| { |
| return (DDR_A (ddr1) == DDR_A (ddr2) && DDR_B (ddr1) == DDR_B (ddr2)); |
| } |
| |
| /* The loop (nest) to be distributed. */ |
| static vec<loop_p> loop_nest; |
| |
| /* Vector of data references in the loop to be distributed. */ |
| static vec<data_reference_p> datarefs_vec; |
| |
| /* Store index of data reference in aux field. */ |
| #define DR_INDEX(dr) ((uintptr_t) (dr)->aux) |
| |
| /* Hash table for data dependence relation in the loop to be distributed. */ |
| static hash_table<ddr_hasher> *ddrs_table; |
| |
| /* A Reduced Dependence Graph (RDG) vertex representing a statement. */ |
| struct rdg_vertex |
| { |
| /* The statement represented by this vertex. */ |
| gimple *stmt; |
| |
| /* Vector of data-references in this statement. */ |
| vec<data_reference_p> datarefs; |
| |
| /* True when the statement contains a write to memory. */ |
| bool has_mem_write; |
| |
| /* True when the statement contains a read from memory. */ |
| bool has_mem_reads; |
| }; |
| |
| #define RDGV_STMT(V) ((struct rdg_vertex *) ((V)->data))->stmt |
| #define RDGV_DATAREFS(V) ((struct rdg_vertex *) ((V)->data))->datarefs |
| #define RDGV_HAS_MEM_WRITE(V) ((struct rdg_vertex *) ((V)->data))->has_mem_write |
| #define RDGV_HAS_MEM_READS(V) ((struct rdg_vertex *) ((V)->data))->has_mem_reads |
| #define RDG_STMT(RDG, I) RDGV_STMT (&(RDG->vertices[I])) |
| #define RDG_DATAREFS(RDG, I) RDGV_DATAREFS (&(RDG->vertices[I])) |
| #define RDG_MEM_WRITE_STMT(RDG, I) RDGV_HAS_MEM_WRITE (&(RDG->vertices[I])) |
| #define RDG_MEM_READS_STMT(RDG, I) RDGV_HAS_MEM_READS (&(RDG->vertices[I])) |
| |
| /* Data dependence type. */ |
| |
| enum rdg_dep_type |
| { |
| /* Read After Write (RAW). */ |
| flow_dd = 'f', |
| |
| /* Control dependence (execute conditional on). */ |
| control_dd = 'c' |
| }; |
| |
| /* Dependence information attached to an edge of the RDG. */ |
| |
| struct rdg_edge |
| { |
| /* Type of the dependence. */ |
| enum rdg_dep_type type; |
| }; |
| |
| #define RDGE_TYPE(E) ((struct rdg_edge *) ((E)->data))->type |
| |
| /* Dump vertex I in RDG to FILE. */ |
| |
| static void |
| dump_rdg_vertex (FILE *file, struct graph *rdg, int i) |
| { |
| struct vertex *v = &(rdg->vertices[i]); |
| struct graph_edge *e; |
| |
| fprintf (file, "(vertex %d: (%s%s) (in:", i, |
| RDG_MEM_WRITE_STMT (rdg, i) ? "w" : "", |
| RDG_MEM_READS_STMT (rdg, i) ? "r" : ""); |
| |
| if (v->pred) |
| for (e = v->pred; e; e = e->pred_next) |
| fprintf (file, " %d", e->src); |
| |
| fprintf (file, ") (out:"); |
| |
| if (v->succ) |
| for (e = v->succ; e; e = e->succ_next) |
| fprintf (file, " %d", e->dest); |
| |
| fprintf (file, ")\n"); |
| print_gimple_stmt (file, RDGV_STMT (v), 0, TDF_VOPS|TDF_MEMSYMS); |
| fprintf (file, ")\n"); |
| } |
| |
| /* Call dump_rdg_vertex on stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_rdg_vertex (struct graph *rdg, int i) |
| { |
| dump_rdg_vertex (stderr, rdg, i); |
| } |
| |
| /* Dump the reduced dependence graph RDG to FILE. */ |
| |
| static void |
| dump_rdg (FILE *file, struct graph *rdg) |
| { |
| fprintf (file, "(rdg\n"); |
| for (int i = 0; i < rdg->n_vertices; i++) |
| dump_rdg_vertex (file, rdg, i); |
| fprintf (file, ")\n"); |
| } |
| |
| /* Call dump_rdg on stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_rdg (struct graph *rdg) |
| { |
| dump_rdg (stderr, rdg); |
| } |
| |
| static void |
| dot_rdg_1 (FILE *file, struct graph *rdg) |
| { |
| int i; |
| pretty_printer buffer; |
| pp_needs_newline (&buffer) = false; |
| buffer.buffer->stream = file; |
| |
| fprintf (file, "digraph RDG {\n"); |
| |
| for (i = 0; i < rdg->n_vertices; i++) |
| { |
| struct vertex *v = &(rdg->vertices[i]); |
| struct graph_edge *e; |
| |
| fprintf (file, "%d [label=\"[%d] ", i, i); |
| pp_gimple_stmt_1 (&buffer, RDGV_STMT (v), 0, TDF_SLIM); |
| pp_flush (&buffer); |
| fprintf (file, "\"]\n"); |
| |
| /* Highlight reads from memory. */ |
| if (RDG_MEM_READS_STMT (rdg, i)) |
| fprintf (file, "%d [style=filled, fillcolor=green]\n", i); |
| |
| /* Highlight stores to memory. */ |
| if (RDG_MEM_WRITE_STMT (rdg, i)) |
| fprintf (file, "%d [style=filled, fillcolor=red]\n", i); |
| |
| if (v->succ) |
| for (e = v->succ; e; e = e->succ_next) |
| switch (RDGE_TYPE (e)) |
| { |
| case flow_dd: |
| /* These are the most common dependences: don't print these. */ |
| fprintf (file, "%d -> %d \n", i, e->dest); |
| break; |
| |
| case control_dd: |
| fprintf (file, "%d -> %d [label=control] \n", i, e->dest); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| fprintf (file, "}\n\n"); |
| } |
| |
| /* Display the Reduced Dependence Graph using dotty. */ |
| |
| DEBUG_FUNCTION void |
| dot_rdg (struct graph *rdg) |
| { |
| /* When debugging, you may want to enable the following code. */ |
| #ifdef HAVE_POPEN |
| FILE *file = popen ("dot -Tx11", "w"); |
| if (!file) |
| return; |
| dot_rdg_1 (file, rdg); |
| fflush (file); |
| close (fileno (file)); |
| pclose (file); |
| #else |
| dot_rdg_1 (stderr, rdg); |
| #endif |
| } |
| |
| /* Returns the index of STMT in RDG. */ |
| |
| static int |
| rdg_vertex_for_stmt (struct graph *rdg ATTRIBUTE_UNUSED, gimple *stmt) |
| { |
| int index = gimple_uid (stmt); |
| gcc_checking_assert (index == -1 || RDG_STMT (rdg, index) == stmt); |
| return index; |
| } |
| |
| /* Creates dependence edges in RDG for all the uses of DEF. IDEF is |
| the index of DEF in RDG. */ |
| |
| static void |
| create_rdg_edges_for_scalar (struct graph *rdg, tree def, int idef) |
| { |
| use_operand_p imm_use_p; |
| imm_use_iterator iterator; |
| |
| FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, def) |
| { |
| struct graph_edge *e; |
| int use = rdg_vertex_for_stmt (rdg, USE_STMT (imm_use_p)); |
| |
| if (use < 0) |
| continue; |
| |
| e = add_edge (rdg, idef, use); |
| e->data = XNEW (struct rdg_edge); |
| RDGE_TYPE (e) = flow_dd; |
| } |
| } |
| |
| /* Creates an edge for the control dependences of BB to the vertex V. */ |
| |
| static void |
| create_edge_for_control_dependence (struct graph *rdg, basic_block bb, |
| int v, control_dependences *cd) |
| { |
| bitmap_iterator bi; |
| unsigned edge_n; |
| EXECUTE_IF_SET_IN_BITMAP (cd->get_edges_dependent_on (bb->index), |
| 0, edge_n, bi) |
| { |
| basic_block cond_bb = cd->get_edge_src (edge_n); |
| gimple *stmt = last_stmt (cond_bb); |
| if (stmt && is_ctrl_stmt (stmt)) |
| { |
| struct graph_edge *e; |
| int c = rdg_vertex_for_stmt (rdg, stmt); |
| if (c < 0) |
| continue; |
| |
| e = add_edge (rdg, c, v); |
| e->data = XNEW (struct rdg_edge); |
| RDGE_TYPE (e) = control_dd; |
| } |
| } |
| } |
| |
| /* Creates the edges of the reduced dependence graph RDG. */ |
| |
| static void |
| create_rdg_flow_edges (struct graph *rdg) |
| { |
| int i; |
| def_operand_p def_p; |
| ssa_op_iter iter; |
| |
| for (i = 0; i < rdg->n_vertices; i++) |
| FOR_EACH_PHI_OR_STMT_DEF (def_p, RDG_STMT (rdg, i), |
| iter, SSA_OP_DEF) |
| create_rdg_edges_for_scalar (rdg, DEF_FROM_PTR (def_p), i); |
| } |
| |
| /* Creates the edges of the reduced dependence graph RDG. */ |
| |
| static void |
| create_rdg_cd_edges (struct graph *rdg, control_dependences *cd, loop_p loop) |
| { |
| int i; |
| |
| for (i = 0; i < rdg->n_vertices; i++) |
| { |
| gimple *stmt = RDG_STMT (rdg, i); |
| if (gimple_code (stmt) == GIMPLE_PHI) |
| { |
| edge_iterator ei; |
| edge e; |
| FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->preds) |
| if (flow_bb_inside_loop_p (loop, e->src)) |
| create_edge_for_control_dependence (rdg, e->src, i, cd); |
| } |
| else |
| create_edge_for_control_dependence (rdg, gimple_bb (stmt), i, cd); |
| } |
| } |
| |
| /* Build the vertices of the reduced dependence graph RDG. Return false |
| if that failed. */ |
| |
| static bool |
| create_rdg_vertices (struct graph *rdg, vec<gimple *> stmts, loop_p loop) |
| { |
| int i; |
| gimple *stmt; |
| |
| FOR_EACH_VEC_ELT (stmts, i, stmt) |
| { |
| struct vertex *v = &(rdg->vertices[i]); |
| |
| /* Record statement to vertex mapping. */ |
| gimple_set_uid (stmt, i); |
| |
| v->data = XNEW (struct rdg_vertex); |
| RDGV_STMT (v) = stmt; |
| RDGV_DATAREFS (v).create (0); |
| RDGV_HAS_MEM_WRITE (v) = false; |
| RDGV_HAS_MEM_READS (v) = false; |
| if (gimple_code (stmt) == GIMPLE_PHI) |
| continue; |
| |
| unsigned drp = datarefs_vec.length (); |
| if (!find_data_references_in_stmt (loop, stmt, &datarefs_vec)) |
| return false; |
| for (unsigned j = drp; j < datarefs_vec.length (); ++j) |
| { |
| data_reference_p dr = datarefs_vec[j]; |
| if (DR_IS_READ (dr)) |
| RDGV_HAS_MEM_READS (v) = true; |
| else |
| RDGV_HAS_MEM_WRITE (v) = true; |
| RDGV_DATAREFS (v).safe_push (dr); |
| } |
| } |
| return true; |
| } |
| |
| /* Array mapping basic block's index to its topological order. */ |
| static int *bb_top_order_index; |
| /* And size of the array. */ |
| static int bb_top_order_index_size; |
| |
| /* If X has a smaller topological sort number than Y, returns -1; |
| if greater, returns 1. */ |
| |
| static int |
| bb_top_order_cmp (const void *x, const void *y) |
| { |
| basic_block bb1 = *(const basic_block *) x; |
| basic_block bb2 = *(const basic_block *) y; |
| |
| gcc_assert (bb1->index < bb_top_order_index_size |
| && bb2->index < bb_top_order_index_size); |
| gcc_assert (bb1 == bb2 |
| || bb_top_order_index[bb1->index] |
| != bb_top_order_index[bb2->index]); |
| |
| return (bb_top_order_index[bb1->index] - bb_top_order_index[bb2->index]); |
| } |
| |
| /* Initialize STMTS with all the statements of LOOP. We use topological |
| order to discover all statements. The order is important because |
| generate_loops_for_partition is using the same traversal for identifying |
| statements in loop copies. */ |
| |
| static void |
| stmts_from_loop (struct loop *loop, vec<gimple *> *stmts) |
| { |
| unsigned int i; |
| basic_block *bbs = get_loop_body_in_custom_order (loop, bb_top_order_cmp); |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| basic_block bb = bbs[i]; |
| |
| for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi); |
| gsi_next (&bsi)) |
| if (!virtual_operand_p (gimple_phi_result (bsi.phi ()))) |
| stmts->safe_push (bsi.phi ()); |
| |
| for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); |
| gsi_next (&bsi)) |
| { |
| gimple *stmt = gsi_stmt (bsi); |
| if (gimple_code (stmt) != GIMPLE_LABEL && !is_gimple_debug (stmt)) |
| stmts->safe_push (stmt); |
| } |
| } |
| |
| free (bbs); |
| } |
| |
| /* Free the reduced dependence graph RDG. */ |
| |
| static void |
| free_rdg (struct graph *rdg) |
| { |
| int i; |
| |
| for (i = 0; i < rdg->n_vertices; i++) |
| { |
| struct vertex *v = &(rdg->vertices[i]); |
| struct graph_edge *e; |
| |
| for (e = v->succ; e; e = e->succ_next) |
| free (e->data); |
| |
| if (v->data) |
| { |
| gimple_set_uid (RDGV_STMT (v), -1); |
| (RDGV_DATAREFS (v)).release (); |
| free (v->data); |
| } |
| } |
| |
| free_graph (rdg); |
| } |
| |
| /* Build the Reduced Dependence Graph (RDG) with one vertex per statement of |
| LOOP, and one edge per flow dependence or control dependence from control |
| dependence CD. During visiting each statement, data references are also |
| collected and recorded in global data DATAREFS_VEC. */ |
| |
| static struct graph * |
| build_rdg (struct loop *loop, control_dependences *cd) |
| { |
| struct graph *rdg; |
| |
| /* Create the RDG vertices from the stmts of the loop nest. */ |
| auto_vec<gimple *, 10> stmts; |
| stmts_from_loop (loop, &stmts); |
| rdg = new_graph (stmts.length ()); |
| if (!create_rdg_vertices (rdg, stmts, loop)) |
| { |
| free_rdg (rdg); |
| return NULL; |
| } |
| stmts.release (); |
| |
| create_rdg_flow_edges (rdg); |
| if (cd) |
| create_rdg_cd_edges (rdg, cd, loop); |
| |
| return rdg; |
| } |
| |
| |
| /* Kind of distributed loop. */ |
| enum partition_kind { |
| PKIND_NORMAL, |
| /* Partial memset stands for a paritition can be distributed into a loop |
| of memset calls, rather than a single memset call. It's handled just |
| like a normal parition, i.e, distributed as separate loop, no memset |
| call is generated. |
| |
| Note: This is a hacking fix trying to distribute ZERO-ing stmt in a |
| loop nest as deep as possible. As a result, parloop achieves better |
| parallelization by parallelizing deeper loop nest. This hack should |
| be unnecessary and removed once distributed memset can be understood |
| and analyzed in data reference analysis. See PR82604 for more. */ |
| PKIND_PARTIAL_MEMSET, |
| PKIND_MEMSET, PKIND_MEMCPY, PKIND_MEMMOVE |
| }; |
| |
| /* Type of distributed loop. */ |
| enum partition_type { |
| /* The distributed loop can be executed parallelly. */ |
| PTYPE_PARALLEL = 0, |
| /* The distributed loop has to be executed sequentially. */ |
| PTYPE_SEQUENTIAL |
| }; |
| |
| /* Builtin info for loop distribution. */ |
| struct builtin_info |
| { |
| /* data-references a kind != PKIND_NORMAL partition is about. */ |
| data_reference_p dst_dr; |
| data_reference_p src_dr; |
| /* Base address and size of memory objects operated by the builtin. Note |
| both dest and source memory objects must have the same size. */ |
| tree dst_base; |
| tree src_base; |
| tree size; |
| /* Base and offset part of dst_base after stripping constant offset. This |
| is only used in memset builtin distribution for now. */ |
| tree dst_base_base; |
| unsigned HOST_WIDE_INT dst_base_offset; |
| }; |
| |
| /* Partition for loop distribution. */ |
| struct partition |
| { |
| /* Statements of the partition. */ |
| bitmap stmts; |
| /* True if the partition defines variable which is used outside of loop. */ |
| bool reduction_p; |
| enum partition_kind kind; |
| enum partition_type type; |
| /* Data references in the partition. */ |
| bitmap datarefs; |
| /* Information of builtin parition. */ |
| struct builtin_info *builtin; |
| }; |
| |
| |
| /* Allocate and initialize a partition from BITMAP. */ |
| |
| static partition * |
| partition_alloc (void) |
| { |
| partition *partition = XCNEW (struct partition); |
| partition->stmts = BITMAP_ALLOC (NULL); |
| partition->reduction_p = false; |
| partition->kind = PKIND_NORMAL; |
| partition->datarefs = BITMAP_ALLOC (NULL); |
| return partition; |
| } |
| |
| /* Free PARTITION. */ |
| |
| static void |
| partition_free (partition *partition) |
| { |
| BITMAP_FREE (partition->stmts); |
| BITMAP_FREE (partition->datarefs); |
| if (partition->builtin) |
| free (partition->builtin); |
| |
| free (partition); |
| } |
| |
| /* Returns true if the partition can be generated as a builtin. */ |
| |
| static bool |
| partition_builtin_p (partition *partition) |
| { |
| return partition->kind > PKIND_PARTIAL_MEMSET; |
| } |
| |
| /* Returns true if the partition contains a reduction. */ |
| |
| static bool |
| partition_reduction_p (partition *partition) |
| { |
| return partition->reduction_p; |
| } |
| |
| /* Partitions are fused because of different reasons. */ |
| enum fuse_type |
| { |
| FUSE_NON_BUILTIN = 0, |
| FUSE_REDUCTION = 1, |
| FUSE_SHARE_REF = 2, |
| FUSE_SAME_SCC = 3, |
| FUSE_FINALIZE = 4 |
| }; |
| |
| /* Description on different fusing reason. */ |
| static const char *fuse_message[] = { |
| "they are non-builtins", |
| "they have reductions", |
| "they have shared memory refs", |
| "they are in the same dependence scc", |
| "there is no point to distribute loop"}; |
| |
| static void |
| update_type_for_merge (struct graph *, partition *, partition *); |
| |
| /* Merge PARTITION into the partition DEST. RDG is the reduced dependence |
| graph and we update type for result partition if it is non-NULL. */ |
| |
| static void |
| partition_merge_into (struct graph *rdg, partition *dest, |
| partition *partition, enum fuse_type ft) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Fuse partitions because %s:\n", fuse_message[ft]); |
| fprintf (dump_file, " Part 1: "); |
| dump_bitmap (dump_file, dest->stmts); |
| fprintf (dump_file, " Part 2: "); |
| dump_bitmap (dump_file, partition->stmts); |
| } |
| |
| dest->kind = PKIND_NORMAL; |
| if (dest->type == PTYPE_PARALLEL) |
| dest->type = partition->type; |
| |
| bitmap_ior_into (dest->stmts, partition->stmts); |
| if (partition_reduction_p (partition)) |
| dest->reduction_p = true; |
| |
| /* Further check if any data dependence prevents us from executing the |
| new partition parallelly. */ |
| if (dest->type == PTYPE_PARALLEL && rdg != NULL) |
| update_type_for_merge (rdg, dest, partition); |
| |
| bitmap_ior_into (dest->datarefs, partition->datarefs); |
| } |
| |
| |
| /* Returns true when DEF is an SSA_NAME defined in LOOP and used after |
| the LOOP. */ |
| |
| static bool |
| ssa_name_has_uses_outside_loop_p (tree def, loop_p loop) |
| { |
| imm_use_iterator imm_iter; |
| use_operand_p use_p; |
| |
| FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def) |
| { |
| if (is_gimple_debug (USE_STMT (use_p))) |
| continue; |
| |
| basic_block use_bb = gimple_bb (USE_STMT (use_p)); |
| if (!flow_bb_inside_loop_p (loop, use_bb)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Returns true when STMT defines a scalar variable used after the |
| loop LOOP. */ |
| |
| static bool |
| stmt_has_scalar_dependences_outside_loop (loop_p loop, gimple *stmt) |
| { |
| def_operand_p def_p; |
| ssa_op_iter op_iter; |
| |
| if (gimple_code (stmt) == GIMPLE_PHI) |
| return ssa_name_has_uses_outside_loop_p (gimple_phi_result (stmt), loop); |
| |
| FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, op_iter, SSA_OP_DEF) |
| if (ssa_name_has_uses_outside_loop_p (DEF_FROM_PTR (def_p), loop)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Return a copy of LOOP placed before LOOP. */ |
| |
| static struct loop * |
| copy_loop_before (struct loop *loop) |
| { |
| struct loop *res; |
| edge preheader = loop_preheader_edge (loop); |
| |
| initialize_original_copy_tables (); |
| res = slpeel_tree_duplicate_loop_to_edge_cfg (loop, NULL, preheader); |
| gcc_assert (res != NULL); |
| free_original_copy_tables (); |
| delete_update_ssa (); |
| |
| return res; |
| } |
| |
| /* Creates an empty basic block after LOOP. */ |
| |
| static void |
| create_bb_after_loop (struct loop *loop) |
| { |
| edge exit = single_exit (loop); |
| |
| if (!exit) |
| return; |
| |
| split_edge (exit); |
| } |
| |
| /* Generate code for PARTITION from the code in LOOP. The loop is |
| copied when COPY_P is true. All the statements not flagged in the |
| PARTITION bitmap are removed from the loop or from its copy. The |
| statements are indexed in sequence inside a basic block, and the |
| basic blocks of a loop are taken in dom order. */ |
| |
| static void |
| generate_loops_for_partition (struct loop *loop, partition *partition, |
| bool copy_p) |
| { |
| unsigned i; |
| basic_block *bbs; |
| |
| if (copy_p) |
| { |
| int orig_loop_num = loop->orig_loop_num; |
| loop = copy_loop_before (loop); |
| gcc_assert (loop != NULL); |
| loop->orig_loop_num = orig_loop_num; |
| create_preheader (loop, CP_SIMPLE_PREHEADERS); |
| create_bb_after_loop (loop); |
| } |
| else |
| { |
| /* Origin number is set to the new versioned loop's num. */ |
| gcc_assert (loop->orig_loop_num != loop->num); |
| } |
| |
| /* Remove stmts not in the PARTITION bitmap. */ |
| bbs = get_loop_body_in_dom_order (loop); |
| |
| if (MAY_HAVE_DEBUG_BIND_STMTS) |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| basic_block bb = bbs[i]; |
| |
| for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi); |
| gsi_next (&bsi)) |
| { |
| gphi *phi = bsi.phi (); |
| if (!virtual_operand_p (gimple_phi_result (phi)) |
| && !bitmap_bit_p (partition->stmts, gimple_uid (phi))) |
| reset_debug_uses (phi); |
| } |
| |
| for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) |
| { |
| gimple *stmt = gsi_stmt (bsi); |
| if (gimple_code (stmt) != GIMPLE_LABEL |
| && !is_gimple_debug (stmt) |
| && !bitmap_bit_p (partition->stmts, gimple_uid (stmt))) |
| reset_debug_uses (stmt); |
| } |
| } |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| basic_block bb = bbs[i]; |
| edge inner_exit = NULL; |
| |
| if (loop != bb->loop_father) |
| inner_exit = single_exit (bb->loop_father); |
| |
| for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi);) |
| { |
| gphi *phi = bsi.phi (); |
| if (!virtual_operand_p (gimple_phi_result (phi)) |
| && !bitmap_bit_p (partition->stmts, gimple_uid (phi))) |
| remove_phi_node (&bsi, true); |
| else |
| gsi_next (&bsi); |
| } |
| |
| for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi);) |
| { |
| gimple *stmt = gsi_stmt (bsi); |
| if (gimple_code (stmt) != GIMPLE_LABEL |
| && !is_gimple_debug (stmt) |
| && !bitmap_bit_p (partition->stmts, gimple_uid (stmt))) |
| { |
| /* In distribution of loop nest, if bb is inner loop's exit_bb, |
| we choose its exit edge/path in order to avoid generating |
| infinite loop. For all other cases, we choose an arbitrary |
| path through the empty CFG part that this unnecessary |
| control stmt controls. */ |
| if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) |
| { |
| if (inner_exit && inner_exit->flags & EDGE_TRUE_VALUE) |
| gimple_cond_make_true (cond_stmt); |
| else |
| gimple_cond_make_false (cond_stmt); |
| update_stmt (stmt); |
| } |
| else if (gimple_code (stmt) == GIMPLE_SWITCH) |
| { |
| gswitch *switch_stmt = as_a <gswitch *> (stmt); |
| gimple_switch_set_index |
| (switch_stmt, CASE_LOW (gimple_switch_label (switch_stmt, 1))); |
| update_stmt (stmt); |
| } |
| else |
| { |
| unlink_stmt_vdef (stmt); |
| gsi_remove (&bsi, true); |
| release_defs (stmt); |
| continue; |
| } |
| } |
| gsi_next (&bsi); |
| } |
| } |
| |
| free (bbs); |
| } |
| |
| /* If VAL memory representation contains the same value in all bytes, |
| return that value, otherwise return -1. |
| E.g. for 0x24242424 return 0x24, for IEEE double |
| 747708026454360457216.0 return 0x44, etc. */ |
| |
| static int |
| const_with_all_bytes_same (tree val) |
| { |
| unsigned char buf[64]; |
| int i, len; |
| |
| if (integer_zerop (val) |
| || (TREE_CODE (val) == CONSTRUCTOR |
| && !TREE_CLOBBER_P (val) |
| && CONSTRUCTOR_NELTS (val) == 0)) |
| return 0; |
| |
| if (real_zerop (val)) |
| { |
| /* Only return 0 for +0.0, not for -0.0, which doesn't have |
| an all bytes same memory representation. Don't transform |
| -0.0 stores into +0.0 even for !HONOR_SIGNED_ZEROS. */ |
| switch (TREE_CODE (val)) |
| { |
| case REAL_CST: |
| if (!real_isneg (TREE_REAL_CST_PTR (val))) |
| return 0; |
| break; |
| case COMPLEX_CST: |
| if (!const_with_all_bytes_same (TREE_REALPART (val)) |
| && !const_with_all_bytes_same (TREE_IMAGPART (val))) |
| return 0; |
| break; |
| case VECTOR_CST: |
| { |
| unsigned int count = vector_cst_encoded_nelts (val); |
| unsigned int j; |
| for (j = 0; j < count; ++j) |
| if (const_with_all_bytes_same (VECTOR_CST_ENCODED_ELT (val, j))) |
| break; |
| if (j == count) |
| return 0; |
| break; |
| } |
| default: |
| break; |
| } |
| } |
| |
| if (CHAR_BIT != 8 || BITS_PER_UNIT != 8) |
| return -1; |
| |
| len = native_encode_expr (val, buf, sizeof (buf)); |
| if (len == 0) |
| return -1; |
| for (i = 1; i < len; i++) |
| if (buf[i] != buf[0]) |
| return -1; |
| return buf[0]; |
| } |
| |
| /* Generate a call to memset for PARTITION in LOOP. */ |
| |
| static void |
| generate_memset_builtin (struct loop *loop, partition *partition) |
| { |
| gimple_stmt_iterator gsi; |
| tree mem, fn, nb_bytes; |
| tree val; |
| struct builtin_info *builtin = partition->builtin; |
| gimple *fn_call; |
| |
| /* The new statements will be placed before LOOP. */ |
| gsi = gsi_last_bb (loop_preheader_edge (loop)->src); |
| |
| nb_bytes = builtin->size; |
| nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE, |
| false, GSI_CONTINUE_LINKING); |
| mem = builtin->dst_base; |
| mem = force_gimple_operand_gsi (&gsi, mem, true, NULL_TREE, |
| false, GSI_CONTINUE_LINKING); |
| |
| /* This exactly matches the pattern recognition in classify_partition. */ |
| val = gimple_assign_rhs1 (DR_STMT (builtin->dst_dr)); |
| /* Handle constants like 0x15151515 and similarly |
| floating point constants etc. where all bytes are the same. */ |
| int bytev = const_with_all_bytes_same (val); |
| if (bytev != -1) |
| val = build_int_cst (integer_type_node, bytev); |
| else if (TREE_CODE (val) == INTEGER_CST) |
| val = fold_convert (integer_type_node, val); |
| else if (!useless_type_conversion_p (integer_type_node, TREE_TYPE (val))) |
| { |
| tree tem = make_ssa_name (integer_type_node); |
| gimple *cstmt = gimple_build_assign (tem, NOP_EXPR, val); |
| gsi_insert_after (&gsi, cstmt, GSI_CONTINUE_LINKING); |
| val = tem; |
| } |
| |
| fn = build_fold_addr_expr (builtin_decl_implicit (BUILT_IN_MEMSET)); |
| fn_call = gimple_build_call (fn, 3, mem, val, nb_bytes); |
| gsi_insert_after (&gsi, fn_call, GSI_CONTINUE_LINKING); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "generated memset"); |
| if (bytev == 0) |
| fprintf (dump_file, " zero\n"); |
| else |
| fprintf (dump_file, "\n"); |
| } |
| } |
| |
| /* Generate a call to memcpy for PARTITION in LOOP. */ |
| |
| static void |
| generate_memcpy_builtin (struct loop *loop, partition *partition) |
| { |
| gimple_stmt_iterator gsi; |
| gimple *fn_call; |
| tree dest, src, fn, nb_bytes; |
| enum built_in_function kind; |
| struct builtin_info *builtin = partition->builtin; |
| |
| /* The new statements will be placed before LOOP. */ |
| gsi = gsi_last_bb (loop_preheader_edge (loop)->src); |
| |
| nb_bytes = builtin->size; |
| nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE, |
| false, GSI_CONTINUE_LINKING); |
| dest = builtin->dst_base; |
| src = builtin->src_base; |
| if (partition->kind == PKIND_MEMCPY |
| || ! ptr_derefs_may_alias_p (dest, src)) |
| kind = BUILT_IN_MEMCPY; |
| else |
| kind = BUILT_IN_MEMMOVE; |
| |
| dest = force_gimple_operand_gsi (&gsi, dest, true, NULL_TREE, |
| false, GSI_CONTINUE_LINKING); |
| src = force_gimple_operand_gsi (&gsi, src, true, NULL_TREE, |
| false, GSI_CONTINUE_LINKING); |
| fn = build_fold_addr_expr (builtin_decl_implicit (kind)); |
| fn_call = gimple_build_call (fn, 3, dest, src, nb_bytes); |
| gsi_insert_after (&gsi, fn_call, GSI_CONTINUE_LINKING); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| if (kind == BUILT_IN_MEMCPY) |
| fprintf (dump_file, "generated memcpy\n"); |
| else |
| fprintf (dump_file, "generated memmove\n"); |
| } |
| } |
| |
| /* Remove and destroy the loop LOOP. */ |
| |
| static void |
| destroy_loop (struct loop *loop) |
| { |
| unsigned nbbs = loop->num_nodes; |
| edge exit = single_exit (loop); |
| basic_block src = loop_preheader_edge (loop)->src, dest = exit->dest; |
| basic_block *bbs; |
| unsigned i; |
| |
| bbs = get_loop_body_in_dom_order (loop); |
| |
| redirect_edge_pred (exit, src); |
| exit->flags &= ~(EDGE_TRUE_VALUE|EDGE_FALSE_VALUE); |
| exit->flags |= EDGE_FALLTHRU; |
| cancel_loop_tree (loop); |
| rescan_loop_exit (exit, false, true); |
| |
| i = nbbs; |
| do |
| { |
| /* We have made sure to not leave any dangling uses of SSA |
| names defined in the loop. With the exception of virtuals. |
| Make sure we replace all uses of virtual defs that will remain |
| outside of the loop with the bare symbol as delete_basic_block |
| will release them. */ |
| --i; |
| for (gphi_iterator gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); |
| gsi_next (&gsi)) |
| { |
| gphi *phi = gsi.phi (); |
| if (virtual_operand_p (gimple_phi_result (phi))) |
| mark_virtual_phi_result_for_renaming (phi); |
| } |
| for (gimple_stmt_iterator gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); |
| gsi_next (&gsi)) |
| { |
| gimple *stmt = gsi_stmt (gsi); |
| tree vdef = gimple_vdef (stmt); |
| if (vdef && TREE_CODE (vdef) == SSA_NAME) |
| mark_virtual_operand_for_renaming (vdef); |
| } |
| delete_basic_block (bbs[i]); |
| } |
| while (i != 0); |
| |
| free (bbs); |
| |
| set_immediate_dominator (CDI_DOMINATORS, dest, |
| recompute_dominator (CDI_DOMINATORS, dest)); |
| } |
| |
| /* Generates code for PARTITION. Return whether LOOP needs to be destroyed. */ |
| |
| static bool |
| generate_code_for_partition (struct loop *loop, |
| partition *partition, bool copy_p) |
| { |
| switch (partition->kind) |
| { |
| case PKIND_NORMAL: |
| case PKIND_PARTIAL_MEMSET: |
| /* Reductions all have to be in the last partition. */ |
| gcc_assert (!partition_reduction_p (partition) |
| || !copy_p); |
| generate_loops_for_partition (loop, partition, copy_p); |
| return false; |
| |
| case PKIND_MEMSET: |
| generate_memset_builtin (loop, partition); |
| break; |
| |
| case PKIND_MEMCPY: |
| case PKIND_MEMMOVE: |
| generate_memcpy_builtin (loop, partition); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| /* Common tail for partitions we turn into a call. If this was the last |
| partition for which we generate code, we have to destroy the loop. */ |
| if (!copy_p) |
| return true; |
| return false; |
| } |
| |
| /* Return data dependence relation for data references A and B. The two |
| data references must be in lexicographic order wrto reduced dependence |
| graph RDG. We firstly try to find ddr from global ddr hash table. If |
| it doesn't exist, compute the ddr and cache it. */ |
| |
| static data_dependence_relation * |
| get_data_dependence (struct graph *rdg, data_reference_p a, data_reference_p b) |
| { |
| struct data_dependence_relation ent, **slot; |
| struct data_dependence_relation *ddr; |
| |
| gcc_assert (DR_IS_WRITE (a) || DR_IS_WRITE (b)); |
| gcc_assert (rdg_vertex_for_stmt (rdg, DR_STMT (a)) |
| <= rdg_vertex_for_stmt (rdg, DR_STMT (b))); |
| ent.a = a; |
| ent.b = b; |
| slot = ddrs_table->find_slot (&ent, INSERT); |
| if (*slot == NULL) |
| { |
| ddr = initialize_data_dependence_relation (a, b, loop_nest); |
| compute_affine_dependence (ddr, loop_nest[0]); |
| *slot = ddr; |
| } |
| |
| return *slot; |
| } |
| |
| /* In reduced dependence graph RDG for loop distribution, return true if |
| dependence between references DR1 and DR2 leads to a dependence cycle |
| and such dependence cycle can't be resolved by runtime alias check. */ |
| |
| static bool |
| data_dep_in_cycle_p (struct graph *rdg, |
| data_reference_p dr1, data_reference_p dr2) |
| { |
| struct data_dependence_relation *ddr; |
| |
| /* Re-shuffle data-refs to be in topological order. */ |
| if (rdg_vertex_for_stmt (rdg, DR_STMT (dr1)) |
| > rdg_vertex_for_stmt (rdg, DR_STMT (dr2))) |
| std::swap (dr1, dr2); |
| |
| ddr = get_data_dependence (rdg, dr1, dr2); |
| |
| /* In case of no data dependence. */ |
| if (DDR_ARE_DEPENDENT (ddr) == chrec_known) |
| return false; |
| /* For unknown data dependence or known data dependence which can't be |
| expressed in classic distance vector, we check if it can be resolved |
| by runtime alias check. If yes, we still consider data dependence |
| as won't introduce data dependence cycle. */ |
| else if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know |
| || DDR_NUM_DIST_VECTS (ddr) == 0) |
| return !runtime_alias_check_p (ddr, NULL, true); |
| else if (DDR_NUM_DIST_VECTS (ddr) > 1) |
| return true; |
| else if (DDR_REVERSED_P (ddr) |
| || lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), 1)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Given reduced dependence graph RDG, PARTITION1 and PARTITION2, update |
| PARTITION1's type after merging PARTITION2 into PARTITION1. */ |
| |
| static void |
| update_type_for_merge (struct graph *rdg, |
| partition *partition1, partition *partition2) |
| { |
| unsigned i, j; |
| bitmap_iterator bi, bj; |
| data_reference_p dr1, dr2; |
| |
| EXECUTE_IF_SET_IN_BITMAP (partition1->datarefs, 0, i, bi) |
| { |
| unsigned start = (partition1 == partition2) ? i + 1 : 0; |
| |
| dr1 = datarefs_vec[i]; |
| EXECUTE_IF_SET_IN_BITMAP (partition2->datarefs, start, j, bj) |
| { |
| dr2 = datarefs_vec[j]; |
| if (DR_IS_READ (dr1) && DR_IS_READ (dr2)) |
| continue; |
| |
| /* Partition can only be executed sequentially if there is any |
| data dependence cycle. */ |
| if (data_dep_in_cycle_p (rdg, dr1, dr2)) |
| { |
| partition1->type = PTYPE_SEQUENTIAL; |
| return; |
| } |
| } |
| } |
| } |
| |
| /* Returns a partition with all the statements needed for computing |
| the vertex V of the RDG, also including the loop exit conditions. */ |
| |
| static partition * |
| build_rdg_partition_for_vertex (struct graph *rdg, int v) |
| { |
| partition *partition = partition_alloc (); |
| auto_vec<int, 3> nodes; |
| unsigned i, j; |
| int x; |
| data_reference_p dr; |
| |
| graphds_dfs (rdg, &v, 1, &nodes, false, NULL); |
| |
| FOR_EACH_VEC_ELT (nodes, i, x) |
| { |
| bitmap_set_bit (partition->stmts, x); |
| |
| for (j = 0; RDG_DATAREFS (rdg, x).iterate (j, &dr); ++j) |
| { |
| unsigned idx = (unsigned) DR_INDEX (dr); |
| gcc_assert (idx < datarefs_vec.length ()); |
| |
| /* Partition can only be executed sequentially if there is any |
| unknown data reference. */ |
| if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) |
| || !DR_INIT (dr) || !DR_STEP (dr)) |
| partition->type = PTYPE_SEQUENTIAL; |
| |
| bitmap_set_bit (partition->datarefs, idx); |
| } |
| } |
| |
| if (partition->type == PTYPE_SEQUENTIAL) |
| return partition; |
| |
| /* Further check if any data dependence prevents us from executing the |
| partition parallelly. */ |
| update_type_for_merge (rdg, partition, partition); |
| |
| return partition; |
| } |
| |
| /* Given PARTITION of LOOP and RDG, record single load/store data references |
| for builtin partition in SRC_DR/DST_DR, return false if there is no such |
| data references. */ |
| |
| static bool |
| find_single_drs (struct loop *loop, struct graph *rdg, partition *partition, |
| data_reference_p *dst_dr, data_reference_p *src_dr) |
| { |
| unsigned i; |
| data_reference_p single_ld = NULL, single_st = NULL; |
| bitmap_iterator bi; |
| |
| EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi) |
| { |
| gimple *stmt = RDG_STMT (rdg, i); |
| data_reference_p dr; |
| |
| if (gimple_code (stmt) == GIMPLE_PHI) |
| continue; |
| |
| /* Any scalar stmts are ok. */ |
| if (!gimple_vuse (stmt)) |
| continue; |
| |
| /* Otherwise just regular loads/stores. */ |
| if (!gimple_assign_single_p (stmt)) |
| return false; |
| |
| /* But exactly one store and/or load. */ |
| for (unsigned j = 0; RDG_DATAREFS (rdg, i).iterate (j, &dr); ++j) |
| { |
| tree type = TREE_TYPE (DR_REF (dr)); |
| |
| /* The memset, memcpy and memmove library calls are only |
| able to deal with generic address space. */ |
| if (!ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (type))) |
| return false; |
| |
| if (DR_IS_READ (dr)) |
| { |
| if (single_ld != NULL) |
| return false; |
| single_ld = dr; |
| } |
| else |
| { |
| if (single_st != NULL) |
| return false; |
| single_st = dr; |
| } |
| } |
| } |
| |
| if (!single_st) |
| return false; |
| |
| /* Bail out if this is a bitfield memory reference. */ |
| if (TREE_CODE (DR_REF (single_st)) == COMPONENT_REF |
| && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (single_st), 1))) |
| return false; |
| |
| /* Data reference must be executed exactly once per iteration of each |
| loop in the loop nest. We only need to check dominance information |
| against the outermost one in a perfect loop nest because a bb can't |
| dominate outermost loop's latch without dominating inner loop's. */ |
| basic_block bb_st = gimple_bb (DR_STMT (single_st)); |
| if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb_st)) |
| return false; |
| |
| if (single_ld) |
| { |
| gimple *store = DR_STMT (single_st), *load = DR_STMT (single_ld); |
| /* Direct aggregate copy or via an SSA name temporary. */ |
| if (load != store |
| && gimple_assign_lhs (load) != gimple_assign_rhs1 (store)) |
| return false; |
| |
| /* Bail out if this is a bitfield memory reference. */ |
| if (TREE_CODE (DR_REF (single_ld)) == COMPONENT_REF |
| && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (single_ld), 1))) |
| return false; |
| |
| /* Load and store must be in the same loop nest. */ |
| basic_block bb_ld = gimple_bb (DR_STMT (single_ld)); |
| if (bb_st->loop_father != bb_ld->loop_father) |
| return false; |
| |
| /* Data reference must be executed exactly once per iteration. |
| Same as single_st, we only need to check against the outermost |
| loop. */ |
| if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb_ld)) |
| return false; |
| |
| edge e = single_exit (bb_st->loop_father); |
| bool dom_ld = dominated_by_p (CDI_DOMINATORS, e->src, bb_ld); |
| bool dom_st = dominated_by_p (CDI_DOMINATORS, e->src, bb_st); |
| if (dom_ld != dom_st) |
| return false; |
| } |
| |
| *src_dr = single_ld; |
| *dst_dr = single_st; |
| return true; |
| } |
| |
| /* Given data reference DR in LOOP_NEST, this function checks the enclosing |
| loops from inner to outer to see if loop's step equals to access size at |
| each level of loop. Return 2 if we can prove this at all level loops; |
| record access base and size in BASE and SIZE; save loop's step at each |
| level of loop in STEPS if it is not null. For example: |
| |
| int arr[100][100][100]; |
| for (i = 0; i < 100; i++) ;steps[2] = 40000 |
| for (j = 100; j > 0; j--) ;steps[1] = -400 |
| for (k = 0; k < 100; k++) ;steps[0] = 4 |
| arr[i][j - 1][k] = 0; ;base = &arr, size = 4000000 |
| |
| Return 1 if we can prove the equality at the innermost loop, but not all |
| level loops. In this case, no information is recorded. |
| |
| Return 0 if no equality can be proven at any level loops. */ |
| |
| static int |
| compute_access_range (loop_p loop_nest, data_reference_p dr, tree *base, |
| tree *size, vec<tree> *steps = NULL) |
| { |
| location_t loc = gimple_location (DR_STMT (dr)); |
| basic_block bb = gimple_bb (DR_STMT (dr)); |
| struct loop *loop = bb->loop_father; |
| tree ref = DR_REF (dr); |
| tree access_base = build_fold_addr_expr (ref); |
| tree access_size = TYPE_SIZE_UNIT (TREE_TYPE (ref)); |
| int res = 0; |
| |
| do { |
| tree scev_fn = analyze_scalar_evolution (loop, access_base); |
| if (TREE_CODE (scev_fn) != POLYNOMIAL_CHREC) |
| return res; |
| |
| access_base = CHREC_LEFT (scev_fn); |
| if (tree_contains_chrecs (access_base, NULL)) |
| return res; |
| |
| tree scev_step = CHREC_RIGHT (scev_fn); |
| /* Only support constant steps. */ |
| if (TREE_CODE (scev_step) != INTEGER_CST) |
| return res; |
| |
| enum ev_direction access_dir = scev_direction (scev_fn); |
| if (access_dir == EV_DIR_UNKNOWN) |
| return res; |
| |
| if (steps != NULL) |
| steps->safe_push (scev_step); |
| |
| scev_step = fold_convert_loc (loc, sizetype, scev_step); |
| /* Compute absolute value of scev step. */ |
| if (access_dir == EV_DIR_DECREASES) |
| scev_step = fold_build1_loc (loc, NEGATE_EXPR, sizetype, scev_step); |
| |
| /* At each level of loop, scev step must equal to access size. In other |
| words, DR must access consecutive memory between loop iterations. */ |
| if (!operand_equal_p (scev_step, access_size, 0)) |
| return res; |
| |
| /* Access stride can be computed for data reference at least for the |
| innermost loop. */ |
| res = 1; |
| |
| /* Compute DR's execution times in loop. */ |
| tree niters = number_of_latch_executions (loop); |
| niters = fold_convert_loc (loc, sizetype, niters); |
| if (dominated_by_p (CDI_DOMINATORS, single_exit (loop)->src, bb)) |
| niters = size_binop_loc (loc, PLUS_EXPR, niters, size_one_node); |
| |
| /* Compute DR's overall access size in loop. */ |
| access_size = fold_build2_loc (loc, MULT_EXPR, sizetype, |
| niters, scev_step); |
| /* Adjust base address in case of negative step. */ |
| if (access_dir == EV_DIR_DECREASES) |
| { |
| tree adj = fold_build2_loc (loc, MINUS_EXPR, sizetype, |
| scev_step, access_size); |
| access_base = fold_build_pointer_plus_loc (loc, access_base, adj); |
| } |
| } while (loop != loop_nest && (loop = loop_outer (loop)) != NULL); |
| |
| *base = access_base; |
| *size = access_size; |
| /* Access stride can be computed for data reference at each level loop. */ |
| return 2; |
| } |
| |
| /* Allocate and return builtin struct. Record information like DST_DR, |
| SRC_DR, DST_BASE, SRC_BASE and SIZE in the allocated struct. */ |
| |
| static struct builtin_info * |
| alloc_builtin (data_reference_p dst_dr, data_reference_p src_dr, |
| tree dst_base, tree src_base, tree size) |
| { |
| struct builtin_info *builtin = XNEW (struct builtin_info); |
| builtin->dst_dr = dst_dr; |
| builtin->src_dr = src_dr; |
| builtin->dst_base = dst_base; |
| builtin->src_base = src_base; |
| builtin->size = size; |
| return builtin; |
| } |
| |
| /* Given data reference DR in loop nest LOOP, classify if it forms builtin |
| memset call. */ |
| |
| static void |
| classify_builtin_st (loop_p loop, partition *partition, data_reference_p dr) |
| { |
| gimple *stmt = DR_STMT (dr); |
| tree base, size, rhs = gimple_assign_rhs1 (stmt); |
| |
| if (const_with_all_bytes_same (rhs) == -1 |
| && (!INTEGRAL_TYPE_P (TREE_TYPE (rhs)) |
| || (TYPE_MODE (TREE_TYPE (rhs)) |
| != TYPE_MODE (unsigned_char_type_node)))) |
| return; |
| |
| if (TREE_CODE (rhs) == SSA_NAME |
| && !SSA_NAME_IS_DEFAULT_DEF (rhs) |
| && flow_bb_inside_loop_p (loop, gimple_bb (SSA_NAME_DEF_STMT (rhs)))) |
| return; |
| |
| int res = compute_access_range (loop, dr, &base, &size); |
| if (res == 0) |
| return; |
| if (res == 1) |
| { |
| partition->kind = PKIND_PARTIAL_MEMSET; |
| return; |
| } |
| |
| poly_uint64 base_offset; |
| unsigned HOST_WIDE_INT const_base_offset; |
| tree base_base = strip_offset (base, &base_offset); |
| if (!base_offset.is_constant (&const_base_offset)) |
| return; |
| |
| struct builtin_info *builtin; |
| builtin = alloc_builtin (dr, NULL, base, NULL_TREE, size); |
| builtin->dst_base_base = base_base; |
| builtin->dst_base_offset = const_base_offset; |
| partition->builtin = builtin; |
| partition->kind = PKIND_MEMSET; |
| } |
| |
| /* Given data references DST_DR and SRC_DR in loop nest LOOP and RDG, classify |
| if it forms builtin memcpy or memmove call. */ |
| |
| static void |
| classify_builtin_ldst (loop_p loop, struct graph *rdg, partition *partition, |
| data_reference_p dst_dr, data_reference_p src_dr) |
| { |
| tree base, size, src_base, src_size; |
| auto_vec<tree> dst_steps, src_steps; |
| |
| /* Compute access range of both load and store. */ |
| int res = compute_access_range (loop, dst_dr, &base, &size, &dst_steps); |
| if (res != 2) |
| return; |
| res = compute_access_range (loop, src_dr, &src_base, &src_size, &src_steps); |
| if (res != 2) |
| return; |
| |
| /* They much have the same access size. */ |
| if (!operand_equal_p (size, src_size, 0)) |
| return; |
| |
| /* Load and store in loop nest must access memory in the same way, i.e, |
| their must have the same steps in each loop of the nest. */ |
| if (dst_steps.length () != src_steps.length ()) |
| return; |
| for (unsigned i = 0; i < dst_steps.length (); ++i) |
| if (!operand_equal_p (dst_steps[i], src_steps[i], 0)) |
| return; |
| |
| /* Now check that if there is a dependence. */ |
| ddr_p ddr = get_data_dependence (rdg, src_dr, dst_dr); |
| |
| /* Classify as memcpy if no dependence between load and store. */ |
| if (DDR_ARE_DEPENDENT (ddr) == chrec_known) |
| { |
| partition->builtin = alloc_builtin (dst_dr, src_dr, base, src_base, size); |
| partition->kind = PKIND_MEMCPY; |
| return; |
| } |
| |
| /* Can't do memmove in case of unknown dependence or dependence without |
| classical distance vector. */ |
| if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know |
| || DDR_NUM_DIST_VECTS (ddr) == 0) |
| return; |
| |
| unsigned i; |
| lambda_vector dist_v; |
| int num_lev = (DDR_LOOP_NEST (ddr)).length (); |
| FOR_EACH_VEC_ELT (DDR_DIST_VECTS (ddr), i, dist_v) |
| { |
| unsigned dep_lev = dependence_level (dist_v, num_lev); |
| /* Can't do memmove if load depends on store. */ |
| if (dep_lev > 0 && dist_v[dep_lev - 1] > 0 && !DDR_REVERSED_P (ddr)) |
| return; |
| } |
| |
| partition->builtin = alloc_builtin (dst_dr, src_dr, base, src_base, size); |
| partition->kind = PKIND_MEMMOVE; |
| return; |
| } |
| |
| /* Classifies the builtin kind we can generate for PARTITION of RDG and LOOP. |
| For the moment we detect memset, memcpy and memmove patterns. Bitmap |
| STMT_IN_ALL_PARTITIONS contains statements belonging to all partitions. */ |
| |
| static void |
| classify_partition (loop_p loop, struct graph *rdg, partition *partition, |
| bitmap stmt_in_all_partitions) |
| { |
| bitmap_iterator bi; |
| unsigned i; |
| data_reference_p single_ld = NULL, single_st = NULL; |
| bool volatiles_p = false, has_reduction = false; |
| |
| EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi) |
| { |
| gimple *stmt = RDG_STMT (rdg, i); |
| |
| if (gimple_has_volatile_ops (stmt)) |
| volatiles_p = true; |
| |
| /* If the stmt is not included by all partitions and there is uses |
| outside of the loop, then mark the partition as reduction. */ |
| if (stmt_has_scalar_dependences_outside_loop (loop, stmt)) |
| { |
| /* Due to limitation in the transform phase we have to fuse all |
| reduction partitions. As a result, this could cancel valid |
| loop distribution especially for loop that induction variable |
| is used outside of loop. To workaround this issue, we skip |
| marking partition as reudction if the reduction stmt belongs |
| to all partitions. In such case, reduction will be computed |
| correctly no matter how partitions are fused/distributed. */ |
| if (!bitmap_bit_p (stmt_in_all_partitions, i)) |
| { |
| partition->reduction_p = true; |
| return; |
| } |
| has_reduction = true; |
| } |
| } |
| |
| /* Perform general partition disqualification for builtins. */ |
| if (volatiles_p |
| /* Simple workaround to prevent classifying the partition as builtin |
| if it contains any use outside of loop. */ |
| || has_reduction |
| || !flag_tree_loop_distribute_patterns) |
| return; |
| |
| /* Find single load/store data references for builtin partition. */ |
| if (!find_single_drs (loop, rdg, partition, &single_st, &single_ld)) |
| return; |
| |
| /* Classify the builtin kind. */ |
| if (single_ld == NULL) |
| classify_builtin_st (loop, partition, single_st); |
| else |
| classify_builtin_ldst (loop, rdg, partition, single_st, single_ld); |
| } |
| |
| /* Returns true when PARTITION1 and PARTITION2 access the same memory |
| object in RDG. */ |
| |
| static bool |
| share_memory_accesses (struct graph *rdg, |
| partition *partition1, partition *partition2) |
| { |
| unsigned i, j; |
| bitmap_iterator bi, bj; |
| data_reference_p dr1, dr2; |
| |
| /* First check whether in the intersection of the two partitions are |
| any loads or stores. Common loads are the situation that happens |
| most often. */ |
| EXECUTE_IF_AND_IN_BITMAP (partition1->stmts, partition2->stmts, 0, i, bi) |
| if (RDG_MEM_WRITE_STMT (rdg, i) |
| || RDG_MEM_READS_STMT (rdg, i)) |
| return true; |
| |
| /* Then check whether the two partitions access the same memory object. */ |
| EXECUTE_IF_SET_IN_BITMAP (partition1->datarefs, 0, i, bi) |
| { |
| dr1 = datarefs_vec[i]; |
| |
| if (!DR_BASE_ADDRESS (dr1) |
| || !DR_OFFSET (dr1) || !DR_INIT (dr1) || !DR_STEP (dr1)) |
| continue; |
| |
| EXECUTE_IF_SET_IN_BITMAP (partition2->datarefs, 0, j, bj) |
| { |
| dr2 = datarefs_vec[j]; |
| |
| if (!DR_BASE_ADDRESS (dr2) |
| || !DR_OFFSET (dr2) || !DR_INIT (dr2) || !DR_STEP (dr2)) |
| continue; |
| |
| if (operand_equal_p (DR_BASE_ADDRESS (dr1), DR_BASE_ADDRESS (dr2), 0) |
| && operand_equal_p (DR_OFFSET (dr1), DR_OFFSET (dr2), 0) |
| && operand_equal_p (DR_INIT (dr1), DR_INIT (dr2), 0) |
| && operand_equal_p (DR_STEP (dr1), DR_STEP (dr2), 0)) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* For each seed statement in STARTING_STMTS, this function builds |
| partition for it by adding depended statements according to RDG. |
| All partitions are recorded in PARTITIONS. */ |
| |
| static void |
| rdg_build_partitions (struct graph *rdg, |
| vec<gimple *> starting_stmts, |
| vec<partition *> *partitions) |
| { |
| auto_bitmap processed; |
| int i; |
| gimple *stmt; |
| |
| FOR_EACH_VEC_ELT (starting_stmts, i, stmt) |
| { |
| int v = rdg_vertex_for_stmt (rdg, stmt); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, |
| "ldist asked to generate code for vertex %d\n", v); |
| |
| /* If the vertex is already contained in another partition so |
| is the partition rooted at it. */ |
| if (bitmap_bit_p (processed, v)) |
| continue; |
| |
| partition *partition = build_rdg_partition_for_vertex (rdg, v); |
| bitmap_ior_into (processed, partition->stmts); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "ldist creates useful %s partition:\n", |
| partition->type == PTYPE_PARALLEL ? "parallel" : "sequent"); |
| bitmap_print (dump_file, partition->stmts, " ", "\n"); |
| } |
| |
| partitions->safe_push (partition); |
| } |
| |
| /* All vertices should have been assigned to at least one partition now, |
| other than vertices belonging to dead code. */ |
| } |
| |
| /* Dump to FILE the PARTITIONS. */ |
| |
| static void |
| dump_rdg_partitions (FILE *file, vec<partition *> partitions) |
| { |
| int i; |
| partition *partition; |
| |
| FOR_EACH_VEC_ELT (partitions, i, partition) |
| debug_bitmap_file (file, partition->stmts); |
| } |
| |
| /* Debug PARTITIONS. */ |
| extern void debug_rdg_partitions (vec<partition *> ); |
| |
| DEBUG_FUNCTION void |
| debug_rdg_partitions (vec<partition *> partitions) |
| { |
| dump_rdg_partitions (stderr, partitions); |
| } |
| |
| /* Returns the number of read and write operations in the RDG. */ |
| |
| static int |
| number_of_rw_in_rdg (struct graph *rdg) |
| { |
| int i, res = 0; |
| |
| for (i = 0; i < rdg->n_vertices; i++) |
| { |
| if (RDG_MEM_WRITE_STMT (rdg, i)) |
| ++res; |
| |
| if (RDG_MEM_READS_STMT (rdg, i)) |
| ++res; |
| } |
| |
| return res; |
| } |
| |
| /* Returns the number of read and write operations in a PARTITION of |
| the RDG. */ |
| |
| static int |
| number_of_rw_in_partition (struct graph *rdg, partition *partition) |
| { |
| int res = 0; |
| unsigned i; |
| bitmap_iterator ii; |
| |
| EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, ii) |
| { |
| if (RDG_MEM_WRITE_STMT (rdg, i)) |
| ++res; |
| |
| if (RDG_MEM_READS_STMT (rdg, i)) |
| ++res; |
| } |
| |
| return res; |
| } |
| |
| /* Returns true when one of the PARTITIONS contains all the read or |
| write operations of RDG. */ |
| |
| static bool |
| partition_contains_all_rw (struct graph *rdg, |
| vec<partition *> partitions) |
| { |
| int i; |
| partition *partition; |
| int nrw = number_of_rw_in_rdg (rdg); |
| |
| FOR_EACH_VEC_ELT (partitions, i, partition) |
| if (nrw == number_of_rw_in_partition (rdg, partition)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Compute partition dependence created by the data references in DRS1 |
| and DRS2, modify and return DIR according to that. IF ALIAS_DDR is |
| not NULL, we record dependence introduced by possible alias between |
| two data references in ALIAS_DDRS; otherwise, we simply ignore such |
| dependence as if it doesn't exist at all. */ |
| |
| static int |
| pg_add_dependence_edges (struct graph *rdg, int dir, |
| bitmap drs1, bitmap drs2, vec<ddr_p> *alias_ddrs) |
| { |
| unsigned i, j; |
| bitmap_iterator bi, bj; |
| data_reference_p dr1, dr2, saved_dr1; |
| |
| /* dependence direction - 0 is no dependence, -1 is back, |
| 1 is forth, 2 is both (we can stop then, merging will occur). */ |
| EXECUTE_IF_SET_IN_BITMAP (drs1, 0, i, bi) |
| { |
| dr1 = datarefs_vec[i]; |
| |
| EXECUTE_IF_SET_IN_BITMAP (drs2, 0, j, bj) |
| { |
| int res, this_dir = 1; |
| ddr_p ddr; |
| |
| dr2 = datarefs_vec[j]; |
| |
| /* Skip all <read, read> data dependence. */ |
| if (DR_IS_READ (dr1) && DR_IS_READ (dr2)) |
| continue; |
| |
| saved_dr1 = dr1; |
| /* Re-shuffle data-refs to be in topological order. */ |
| if (rdg_vertex_for_stmt (rdg, DR_STMT (dr1)) |
| > rdg_vertex_for_stmt (rdg, DR_STMT (dr2))) |
| { |
| std::swap (dr1, dr2); |
| this_dir = -this_dir; |
| } |
| ddr = get_data_dependence (rdg, dr1, dr2); |
| if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) |
| { |
| this_dir = 0; |
| res = data_ref_compare_tree (DR_BASE_ADDRESS (dr1), |
| DR_BASE_ADDRESS (dr2)); |
| /* Be conservative. If data references are not well analyzed, |
| or the two data references have the same base address and |
| offset, add dependence and consider it alias to each other. |
| In other words, the dependence can not be resolved by |
| runtime alias check. */ |
| if (!DR_BASE_ADDRESS (dr1) || !DR_BASE_ADDRESS (dr2) |
| || !DR_OFFSET (dr1) || !DR_OFFSET (dr2) |
| || !DR_INIT (dr1) || !DR_INIT (dr2) |
| || !DR_STEP (dr1) || !tree_fits_uhwi_p (DR_STEP (dr1)) |
| || !DR_STEP (dr2) || !tree_fits_uhwi_p (DR_STEP (dr2)) |
| || res == 0) |
| this_dir = 2; |
| /* Data dependence could be resolved by runtime alias check, |
| record it in ALIAS_DDRS. */ |
| else if (alias_ddrs != NULL) |
| alias_ddrs->safe_push (ddr); |
| /* Or simply ignore it. */ |
| } |
| else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) |
| { |
| if (DDR_REVERSED_P (ddr)) |
| this_dir = -this_dir; |
| |
| /* Known dependences can still be unordered througout the |
| iteration space, see gcc.dg/tree-ssa/ldist-16.c. */ |
| if (DDR_NUM_DIST_VECTS (ddr) != 1) |
| this_dir = 2; |
| /* If the overlap is exact preserve stmt order. */ |
| else if (lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), 1)) |
| ; |
| /* Else as the distance vector is lexicographic positive swap |
| the dependence direction. */ |
| else |
| this_dir = -this_dir; |
| } |
| else |
| this_dir = 0; |
| if (this_dir == 2) |
| return 2; |
| else if (dir == 0) |
| dir = this_dir; |
| else if (this_dir != 0 && dir != this_dir) |
| return 2; |
| /* Shuffle "back" dr1. */ |
| dr1 = saved_dr1; |
| } |
| } |
| return dir; |
| } |
| |
| /* Compare postorder number of the partition graph vertices V1 and V2. */ |
| |
| static int |
| pgcmp (const void *v1_, const void *v2_) |
| { |
| const vertex *v1 = (const vertex *)v1_; |
| const vertex *v2 = (const vertex *)v2_; |
| return v2->post - v1->post; |
| } |
| |
| /* Data attached to vertices of partition dependence graph. */ |
| struct pg_vdata |
| { |
| /* ID of the corresponding partition. */ |
| int id; |
| /* The partition. */ |
| struct partition *partition; |
| }; |
| |
| /* Data attached to edges of partition dependence graph. */ |
| struct pg_edata |
| { |
| /* If the dependence edge can be resolved by runtime alias check, |
| this vector contains data dependence relations for runtime alias |
| check. On the other hand, if the dependence edge is introduced |
| because of compilation time known data dependence, this vector |
| contains nothing. */ |
| vec<ddr_p> alias_ddrs; |
| }; |
| |
| /* Callback data for traversing edges in graph. */ |
| struct pg_edge_callback_data |
| { |
| /* Bitmap contains strong connected components should be merged. */ |
| bitmap sccs_to_merge; |
| /* Array constains component information for all vertices. */ |
| int *vertices_component; |
| /* Vector to record all data dependence relations which are needed |
| to break strong connected components by runtime alias checks. */ |
| vec<ddr_p> *alias_ddrs; |
| }; |
| |
| /* Initialize vertice's data for partition dependence graph PG with |
| PARTITIONS. */ |
| |
| static void |
| init_partition_graph_vertices (struct graph *pg, |
| vec<struct partition *> *partitions) |
| { |
| int i; |
| partition *partition; |
| struct pg_vdata *data; |
| |
| for (i = 0; partitions->iterate (i, &partition); ++i) |
| { |
| data = new pg_vdata; |
| pg->vertices[i].data = data; |
| data->id = i; |
| data->partition = partition; |
| } |
| } |
| |
| /* Add edge <I, J> to partition dependence graph PG. Attach vector of data |
| dependence relations to the EDGE if DDRS isn't NULL. */ |
| |
| static void |
| add_partition_graph_edge (struct graph *pg, int i, int j, vec<ddr_p> *ddrs) |
| { |
| struct graph_edge *e = add_edge (pg, i, j); |
| |
| /* If the edge is attached with data dependence relations, it means this |
| dependence edge can be resolved by runtime alias checks. */ |
| if (ddrs != NULL) |
| { |
| struct pg_edata *data = new pg_edata; |
| |
| gcc_assert (ddrs->length () > 0); |
| e->data = data; |
| data->alias_ddrs = vNULL; |
| data->alias_ddrs.safe_splice (*ddrs); |
| } |
| } |
| |
| /* Callback function for graph travesal algorithm. It returns true |
| if edge E should skipped when traversing the graph. */ |
| |
| static bool |
| pg_skip_alias_edge (struct graph_edge *e) |
| { |
| struct pg_edata *data = (struct pg_edata *)e->data; |
| return (data != NULL && data->alias_ddrs.length () > 0); |
| } |
| |
| /* Callback function freeing data attached to edge E of graph. */ |
| |
| static void |
| free_partition_graph_edata_cb (struct graph *, struct graph_edge *e, void *) |
| { |
| if (e->data != NULL) |
| { |
| struct pg_edata *data = (struct pg_edata *)e->data; |
| data->alias_ddrs.release (); |
| delete data; |
| } |
| } |
| |
| /* Free data attached to vertice of partition dependence graph PG. */ |
| |
| static void |
| free_partition_graph_vdata (struct graph *pg) |
| { |
| int i; |
| struct pg_vdata *data; |
| |
| for (i = 0; i < pg->n_vertices; ++i) |
| { |
| data = (struct pg_vdata *)pg->vertices[i].data; |
| delete data; |
| } |
| } |
| |
| /* Build and return partition dependence graph for PARTITIONS. RDG is |
| reduced dependence graph for the loop to be distributed. If IGNORE_ALIAS_P |
| is true, data dependence caused by possible alias between references |
| is ignored, as if it doesn't exist at all; otherwise all depdendences |
| are considered. */ |
| |
| static struct graph * |
| build_partition_graph (struct graph *rdg, |
| vec<struct partition *> *partitions, |
| bool ignore_alias_p) |
| { |
| int i, j; |
| struct partition *partition1, *partition2; |
| graph *pg = new_graph (partitions->length ()); |
| auto_vec<ddr_p> alias_ddrs, *alias_ddrs_p; |
| |
| alias_ddrs_p = ignore_alias_p ? NULL : &alias_ddrs; |
| |
| init_partition_graph_vertices (pg, partitions); |
| |
| for (i = 0; partitions->iterate (i, &partition1); ++i) |
| { |
| for (j = i + 1; partitions->iterate (j, &partition2); ++j) |
| { |
| /* dependence direction - 0 is no dependence, -1 is back, |
| 1 is forth, 2 is both (we can stop then, merging will occur). */ |
| int dir = 0; |
| |
| /* If the first partition has reduction, add back edge; if the |
| second partition has reduction, add forth edge. This makes |
| sure that reduction partition will be sorted as the last one. */ |
| if (partition_reduction_p (partition1)) |
| dir = -1; |
| else if (partition_reduction_p (partition2)) |
| dir = 1; |
| |
| /* Cleanup the temporary vector. */ |
| alias_ddrs.truncate (0); |
| |
| dir = pg_add_dependence_edges (rdg, dir, partition1->datarefs, |
| partition2->datarefs, alias_ddrs_p); |
| |
| /* Add edge to partition graph if there exists dependence. There |
| are two types of edges. One type edge is caused by compilation |
| time known dependence, this type can not be resolved by runtime |
| alias check. The other type can be resolved by runtime alias |
| check. */ |
| if (dir == 1 || dir == 2 |
| || alias_ddrs.length () > 0) |
| { |
| /* Attach data dependence relations to edge that can be resolved |
| by runtime alias check. */ |
| bool alias_edge_p = (dir != 1 && dir != 2); |
| add_partition_graph_edge (pg, i, j, |
| (alias_edge_p) ? &alias_ddrs : NULL); |
| } |
| if (dir == -1 || dir == 2 |
| || alias_ddrs.length () > 0) |
| { |
| /* Attach data dependence relations to edge that can be resolved |
| by runtime alias check. */ |
| bool alias_edge_p = (dir != -1 && dir != 2); |
| add_partition_graph_edge (pg, j, i, |
| (alias_edge_p) ? &alias_ddrs : NULL); |
| } |
| } |
| } |
| return pg; |
| } |
| |
| /* Sort partitions in PG in descending post order and store them in |
| PARTITIONS. */ |
| |
| static void |
| sort_partitions_by_post_order (struct graph *pg, |
| vec<struct partition *> *partitions) |
| { |
| int i; |
| struct pg_vdata *data; |
| |
| /* Now order the remaining nodes in descending postorder. */ |
| qsort (pg->vertices, pg->n_vertices, sizeof (vertex), pgcmp); |
| partitions->truncate (0); |
| for (i = 0; i < pg->n_vertices; ++i) |
| { |
| data = (struct pg_vdata *)pg->vertices[i].data; |
| if (data->partition) |
| partitions->safe_push (data->partition); |
| } |
| } |
| |
| /* Given reduced dependence graph RDG merge strong connected components |
| of PARTITIONS. If IGNORE_ALIAS_P is true, data dependence caused by |
| possible alias between references is ignored, as if it doesn't exist |
| at all; otherwise all depdendences are considered. */ |
| |
| static void |
| merge_dep_scc_partitions (struct graph *rdg, |
| vec<struct partition *> *partitions, |
| bool ignore_alias_p) |
| { |
| struct partition *partition1, *partition2; |
| struct pg_vdata *data; |
| graph *pg = build_partition_graph (rdg, partitions, ignore_alias_p); |
| int i, j, num_sccs = graphds_scc (pg, NULL); |
| |
| /* Strong connected compoenent means dependence cycle, we cannot distribute |
| them. So fuse them together. */ |
| if ((unsigned) num_sccs < partitions->length ()) |
| { |
| for (i = 0; i < num_sccs; ++i) |
| { |
| for (j = 0; partitions->iterate (j, &partition1); ++j) |
| if (pg->vertices[j].component == i) |
| break; |
| for (j = j + 1; partitions->iterate (j, &partition2); ++j) |
| if (pg->vertices[j].component == i) |
| { |
| partition_merge_into (NULL, partition1, |
| partition2, FUSE_SAME_SCC); |
| partition1->type = PTYPE_SEQUENTIAL; |
| (*partitions)[j] = NULL; |
| partition_free (partition2); |
| data = (struct pg_vdata *)pg->vertices[j].data; |
| data->partition = NULL; |
| } |
| } |
| } |
| |
| sort_partitions_by_post_order (pg, partitions); |
| gcc_assert (partitions->length () == (unsigned)num_sccs); |
| free_partition_graph_vdata (pg); |
| free_graph (pg); |
| } |
| |
| /* Callback function for traversing edge E in graph G. DATA is private |
| callback data. */ |
| |
| static void |
| pg_collect_alias_ddrs (struct graph *g, struct graph_edge *e, void *data) |
| { |
| int i, j, component; |
| struct pg_edge_callback_data *cbdata; |
| struct pg_edata *edata = (struct pg_edata *) e->data; |
| |
| /* If the edge doesn't have attached data dependence, it represents |
| compilation time known dependences. This type dependence cannot |
| be resolved by runtime alias check. */ |
| if (edata == NULL || edata->alias_ddrs.length () == 0) |
| return; |
| |
| cbdata = (struct pg_edge_callback_data *) data; |
| i = e->src; |
| j = e->dest; |
| component = cbdata->vertices_component[i]; |
| /* Vertices are topologically sorted according to compilation time |
| known dependences, so we can break strong connected components |
| by removing edges of the opposite direction, i.e, edges pointing |
| from vertice with smaller post number to vertice with bigger post |
| number. */ |
| if (g->vertices[i].post < g->vertices[j].post |
| /* We only need to remove edges connecting vertices in the same |
| strong connected component to break it. */ |
| && component == cbdata->vertices_component[j] |
| /* Check if we want to break the strong connected component or not. */ |
| && !bitmap_bit_p (cbdata->sccs_to_merge, component)) |
| cbdata->alias_ddrs->safe_splice (edata->alias_ddrs); |
| } |
| |
| /* This is the main function breaking strong conected components in |
| PARTITIONS giving reduced depdendence graph RDG. Store data dependence |
| relations for runtime alias check in ALIAS_DDRS. */ |
| |
| static void |
| break_alias_scc_partitions (struct graph *rdg, |
| vec<struct partition *> *partitions, |
| vec<ddr_p> *alias_ddrs) |
| { |
| int i, j, k, num_sccs, num_sccs_no_alias; |
| /* Build partition dependence graph. */ |
| graph *pg = build_partition_graph (rdg, partitions, false); |
| |
| alias_ddrs->truncate (0); |
| /* Find strong connected components in the graph, with all dependence edges |
| considered. */ |
| num_sccs = graphds_scc (pg, NULL); |
| /* All SCCs now can be broken by runtime alias checks because SCCs caused by |
| compilation time known dependences are merged before this function. */ |
| if ((unsigned) num_sccs < partitions->length ()) |
| { |
| struct pg_edge_callback_data cbdata; |
| auto_bitmap sccs_to_merge; |
| auto_vec<enum partition_type> scc_types; |
| struct partition *partition, *first; |
| |
| /* If all partitions in a SCC have the same type, we can simply merge the |
| SCC. This loop finds out such SCCS and record them in bitmap. */ |
| bitmap_set_range (sccs_to_merge, 0, (unsigned) num_sccs); |
| for (i = 0; i < num_sccs; ++i) |
| { |
| for (j = 0; partitions->iterate (j, &first); ++j) |
| if (pg->vertices[j].component == i) |
| break; |
| for (++j; partitions->iterate (j, &partition); ++j) |
| { |
| if (pg->vertices[j].component != i) |
| continue; |
| |
| /* Note we Merge partitions of parallel type on purpose, though |
| the result partition is sequential. The reason is vectorizer |
| can do more accurate runtime alias check in this case. Also |
| it results in more conservative distribution. */ |
| if (first->type != partition->type) |
| { |
| bitmap_clear_bit (sccs_to_merge, i); |
| break; |
| } |
| } |
| } |
| |
| /* Initialize callback data for traversing. */ |
| cbdata.sccs_to_merge = sccs_to_merge; |
| cbdata.alias_ddrs = alias_ddrs; |
| cbdata.vertices_component = XNEWVEC (int, pg->n_vertices); |
| /* Record the component information which will be corrupted by next |
| graph scc finding call. */ |
| for (i = 0; i < pg->n_vertices; ++i) |
| cbdata.vertices_component[i] = pg->vertices[i].component; |
| |
| /* Collect data dependences for runtime alias checks to break SCCs. */ |
| if (bitmap_count_bits (sccs_to_merge) != (unsigned) num_sccs) |
| { |
| /* Run SCC finding algorithm again, with alias dependence edges |
| skipped. This is to topologically sort partitions according to |
| compilation time known dependence. Note the topological order |
| is stored in the form of pg's post order number. */ |
| num_sccs_no_alias = graphds_scc (pg, NULL, pg_skip_alias_edge); |
| gcc_assert (partitions->length () == (unsigned) num_sccs_no_alias); |
| /* With topological order, we can construct two subgraphs L and R. |
| L contains edge <x, y> where x < y in terms of post order, while |
| R contains edge <x, y> where x > y. Edges for compilation time |
| known dependence all fall in R, so we break SCCs by removing all |
| (alias) edges of in subgraph L. */ |
| for_each_edge (pg, pg_collect_alias_ddrs, &cbdata); |
| } |
| |
| /* For SCC that doesn't need to be broken, merge it. */ |
| for (i = 0; i < num_sccs; ++i) |
| { |
| if (!bitmap_bit_p (sccs_to_merge, i)) |
| continue; |
| |
| for (j = 0; partitions->iterate (j, &first); ++j) |
| if (cbdata.vertices_component[j] == i) |
| break; |
| for (k = j + 1; partitions->iterate (k, &partition); ++k) |
| { |
| struct pg_vdata *data; |
| |
| if (cbdata.vertices_component[k] != i) |
| continue; |
| |
| /* Update postorder number so that merged reduction partition is |
| sorted after other partitions. */ |
| if (!partition_reduction_p (first) |
| && partition_reduction_p (partition)) |
| { |
| gcc_assert (pg->vertices[k].post < pg->vertices[j].post); |
| pg->vertices[j].post = pg->vertices[k].post; |
| } |
| partition_merge_into (NULL, first, partition, FUSE_SAME_SCC); |
| (*partitions)[k] = NULL; |
| partition_free (partition); |
| data = (struct pg_vdata *)pg->vertices[k].data; |
| gcc_assert (data->id == k); |
| data->partition = NULL; |
| /* The result partition of merged SCC must be sequential. */ |
| first->type = PTYPE_SEQUENTIAL; |
| } |
| } |
| } |
| |
| sort_partitions_by_post_order (pg, partitions); |
| free_partition_graph_vdata (pg); |
| for_each_edge (pg, free_partition_graph_edata_cb, NULL); |
| free_graph (pg); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Possible alias data dependence to break:\n"); |
| dump_data_dependence_relations (dump_file, *alias_ddrs); |
| } |
| } |
| |
| /* Compute and return an expression whose value is the segment length which |
| will be accessed by DR in NITERS iterations. */ |
| |
| static tree |
| data_ref_segment_size (struct data_reference *dr, tree niters) |
| { |
| niters = size_binop (MINUS_EXPR, |
| fold_convert (sizetype, niters), |
| size_one_node); |
| return size_binop (MULT_EXPR, |
| fold_convert (sizetype, DR_STEP (dr)), |
| fold_convert (sizetype, niters)); |
| } |
| |
| /* Return true if LOOP's latch is dominated by statement for data reference |
| DR. */ |
| |
| static inline bool |
| latch_dominated_by_data_ref (struct loop *loop, data_reference *dr) |
| { |
| return dominated_by_p (CDI_DOMINATORS, single_exit (loop)->src, |
| gimple_bb (DR_STMT (dr))); |
| } |
| |
| /* Compute alias check pairs and store them in COMP_ALIAS_PAIRS for LOOP's |
| data dependence relations ALIAS_DDRS. */ |
| |
| static void |
| compute_alias_check_pairs (struct loop *loop, vec<ddr_p> *alias_ddrs, |
| vec<dr_with_seg_len_pair_t> *comp_alias_pairs) |
| { |
| unsigned int i; |
| unsigned HOST_WIDE_INT factor = 1; |
| tree niters_plus_one, niters = number_of_latch_executions (loop); |
| |
| gcc_assert (niters != NULL_TREE && niters != chrec_dont_know); |
| niters = fold_convert (sizetype, niters); |
| niters_plus_one = size_binop (PLUS_EXPR, niters, size_one_node); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Creating alias check pairs:\n"); |
| |
| /* Iterate all data dependence relations and compute alias check pairs. */ |
| for (i = 0; i < alias_ddrs->length (); i++) |
| { |
| ddr_p ddr = (*alias_ddrs)[i]; |
| struct data_reference *dr_a = DDR_A (ddr); |
| struct data_reference *dr_b = DDR_B (ddr); |
| tree seg_length_a, seg_length_b; |
| int comp_res = data_ref_compare_tree (DR_BASE_ADDRESS (dr_a), |
| DR_BASE_ADDRESS (dr_b)); |
| |
| if (comp_res == 0) |
| comp_res = data_ref_compare_tree (DR_OFFSET (dr_a), DR_OFFSET (dr_b)); |
| gcc_assert (comp_res != 0); |
| |
| if (latch_dominated_by_data_ref (loop, dr_a)) |
| seg_length_a = data_ref_segment_size (dr_a, niters_plus_one); |
| else |
| seg_length_a = data_ref_segment_size (dr_a, niters); |
| |
| if (latch_dominated_by_data_ref (loop, dr_b)) |
| seg_length_b = data_ref_segment_size (dr_b, niters_plus_one); |
| else |
| seg_length_b = data_ref_segment_size (dr_b, niters); |
| |
| unsigned HOST_WIDE_INT access_size_a |
| = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr_a)))); |
| unsigned HOST_WIDE_INT access_size_b |
| = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr_b)))); |
| unsigned int align_a = TYPE_ALIGN_UNIT (TREE_TYPE (DR_REF (dr_a))); |
| unsigned int align_b = TYPE_ALIGN_UNIT (TREE_TYPE (DR_REF (dr_b))); |
| |
| dr_with_seg_len_pair_t dr_with_seg_len_pair |
| (dr_with_seg_len (dr_a, seg_length_a, access_size_a, align_a), |
| dr_with_seg_len (dr_b, seg_length_b, access_size_b, align_b)); |
| |
| /* Canonicalize pairs by sorting the two DR members. */ |
| if (comp_res > 0) |
| std::swap (dr_with_seg_len_pair.first, dr_with_seg_len_pair.second); |
| |
| comp_alias_pairs->safe_push (dr_with_seg_len_pair); |
| } |
| |
| if (tree_fits_uhwi_p (niters)) |
| factor = tree_to_uhwi (niters); |
| |
| /* Prune alias check pairs. */ |
| prune_runtime_alias_test_list (comp_alias_pairs, factor); |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, |
| "Improved number of alias checks from %d to %d\n", |
| alias_ddrs->length (), comp_alias_pairs->length ()); |
| } |
| |
| /* Given data dependence relations in ALIAS_DDRS, generate runtime alias |
| checks and version LOOP under condition of these runtime alias checks. */ |
| |
| static void |
| version_loop_by_alias_check (struct loop *loop, vec<ddr_p> *alias_ddrs) |
| { |
| profile_probability prob; |
| basic_block cond_bb; |
| struct loop *nloop; |
| tree lhs, arg0, cond_expr = NULL_TREE; |
| gimple_seq cond_stmts = NULL; |
| gimple *call_stmt = NULL; |
| auto_vec<dr_with_seg_len_pair_t> comp_alias_pairs; |
| |
| /* Generate code for runtime alias checks if necessary. */ |
| gcc_assert (alias_ddrs->length () > 0); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, |
| "Version loop <%d> with runtime alias check\n", loop->num); |
| |
| compute_alias_check_pairs (loop, alias_ddrs, &comp_alias_pairs); |
| create_runtime_alias_checks (loop, &comp_alias_pairs, &cond_expr); |
| cond_expr = force_gimple_operand_1 (cond_expr, &cond_stmts, |
| is_gimple_val, NULL_TREE); |
| |
| /* Depend on vectorizer to fold IFN_LOOP_DIST_ALIAS. */ |
| if (flag_tree_loop_vectorize) |
| { |
| /* Generate internal function call for loop distribution alias check. */ |
| call_stmt = gimple_build_call_internal (IFN_LOOP_DIST_ALIAS, |
| 2, NULL_TREE, cond_expr); |
| lhs = make_ssa_name (boolean_type_node); |
| gimple_call_set_lhs (call_stmt, lhs); |
| } |
| else |
| lhs = cond_expr; |
| |
| prob = profile_probability::guessed_always ().apply_scale (9, 10); |
| initialize_original_copy_tables (); |
| nloop = loop_version (loop, lhs, &cond_bb, prob, prob.invert (), |
| prob, prob.invert (), true); |
| free_original_copy_tables (); |
| /* Record the original loop number in newly generated loops. In case of |
| distribution, the original loop will be distributed and the new loop |
| is kept. */ |
| loop->orig_loop_num = nloop->num; |
| nloop->orig_loop_num = nloop->num; |
| nloop->dont_vectorize = true; |
| nloop->force_vectorize = false; |
| |
| if (call_stmt) |
| { |
| /* Record new loop's num in IFN_LOOP_DIST_ALIAS because the original |
| loop could be destroyed. */ |
| arg0 = build_int_cst (integer_type_node, loop->orig_loop_num); |
| gimple_call_set_arg (call_stmt, 0, arg0); |
| gimple_seq_add_stmt_without_update (&cond_stmts, call_stmt); |
| } |
| |
| if (cond_stmts) |
| { |
| gimple_stmt_iterator cond_gsi = gsi_last_bb (cond_bb); |
| gsi_insert_seq_before (&cond_gsi, cond_stmts, GSI_SAME_STMT); |
| } |
| update_ssa (TODO_update_ssa); |
| } |
| |
| /* Return true if loop versioning is needed to distrubute PARTITIONS. |
| ALIAS_DDRS are data dependence relations for runtime alias check. */ |
| |
| static inline bool |
| version_for_distribution_p (vec<struct partition *> *partitions, |
| vec<ddr_p> *alias_ddrs) |
| { |
| /* No need to version loop if we have only one partition. */ |
| if (partitions->length () == 1) |
| return false; |
| |
| /* Need to version loop if runtime alias check is necessary. */ |
| return (alias_ddrs->length () > 0); |
| } |
| |
| /* Compare base offset of builtin mem* partitions P1 and P2. */ |
| |
| static bool |
| offset_cmp (struct partition *p1, struct partition *p2) |
| { |
| gcc_assert (p1 != NULL && p1->builtin != NULL); |
| gcc_assert (p2 != NULL && p2->builtin != NULL); |
| return p1->builtin->dst_base_offset < p2->builtin->dst_base_offset; |
| } |
| |
| /* Fuse adjacent memset builtin PARTITIONS if possible. This is a special |
| case optimization transforming below code: |
| |
| __builtin_memset (&obj, 0, 100); |
| _1 = &obj + 100; |
| __builtin_memset (_1, 0, 200); |
| _2 = &obj + 300; |
| __builtin_memset (_2, 0, 100); |
| |
| into: |
| |
| __builtin_memset (&obj, 0, 400); |
| |
| Note we don't have dependence information between different partitions |
| at this point, as a result, we can't handle nonadjacent memset builtin |
| partitions since dependence might be broken. */ |
| |
| static void |
| fuse_memset_builtins (vec<struct partition *> *partitions) |
| { |
| unsigned i, j; |
| struct partition *part1, *part2; |
| tree rhs1, rhs2; |
| |
| for (i = 0; partitions->iterate (i, &part1);) |
| { |
| if (part1->kind != PKIND_MEMSET) |
| { |
| i++; |
| continue; |
| } |
| |
| /* Find sub-array of memset builtins of the same base. Index range |
| of the sub-array is [i, j) with "j > i". */ |
| for (j = i + 1; partitions->iterate (j, &part2); ++j) |
| { |
| if (part2->kind != PKIND_MEMSET |
| || !operand_equal_p (part1->builtin->dst_base_base, |
| part2->builtin->dst_base_base, 0)) |
| break; |
| |
| /* Memset calls setting different values can't be merged. */ |
| rhs1 = gimple_assign_rhs1 (DR_STMT (part1->builtin->dst_dr)); |
| rhs2 = gimple_assign_rhs1 (DR_STMT (part2->builtin->dst_dr)); |
| if (!operand_equal_p (rhs1, rhs2, 0)) |
| break; |
| } |
| |
| /* Stable sort is required in order to avoid breaking dependence. */ |
| std::stable_sort (&(*partitions)[i], |
| &(*partitions)[i] + j - i, offset_cmp); |
| /* Continue with next partition. */ |
| i = j; |
| } |
| |
| /* Merge all consecutive memset builtin partitions. */ |
| for (i = 0; i < partitions->length () - 1;) |
| { |
| part1 = (*partitions)[i]; |
| if (part1->kind != PKIND_MEMSET) |
| { |
| i++; |
| continue; |
| } |
| |
| part2 = (*partitions)[i + 1]; |
| /* Only merge memset partitions of the same base and with constant |
| access sizes. */ |
| if (part2->kind != PKIND_MEMSET |
| || TREE_CODE (part1->builtin->size) != INTEGER_CST |
| || TREE_CODE (part2->builtin->size) != INTEGER_CST |
| || !operand_equal_p (part1->builtin->dst_base_base, |
| part2->builtin->dst_base_base, 0)) |
| { |
| i++; |
| continue; |
| } |
| rhs1 = gimple_assign_rhs1 (DR_STMT (part1->builtin->dst_dr)); |
| rhs2 = gimple_assign_rhs1 (DR_STMT (part2->builtin->dst_dr)); |
| int bytev1 = const_with_all_bytes_same (rhs1); |
| int bytev2 = const_with_all_bytes_same (rhs2); |
| /* Only merge memset partitions of the same value. */ |
| if (bytev1 != bytev2 || bytev1 == -1) |
| { |
| i++; |
| continue; |
| } |
| wide_int end1 = wi::add (part1->builtin->dst_base_offset, |
| wi::to_wide (part1->builtin->size)); |
| /* Only merge adjacent memset partitions. */ |
| if (wi::ne_p (end1, part2->builtin->dst_base_offset)) |
| { |
| i++; |
| continue; |
| } |
| /* Merge partitions[i] and partitions[i+1]. */ |
| part1->builtin->size = fold_build2 (PLUS_EXPR, sizetype, |
| part1->builtin->size, |
| part2->builtin->size); |
| partition_free (part2); |
| partitions->ordered_remove (i + 1); |
| } |
| } |
| |
| /* Fuse PARTITIONS of LOOP if necessary before finalizing distribution. |
| ALIAS_DDRS contains ddrs which need runtime alias check. */ |
| |
| static void |
| finalize_partitions (struct loop *loop, vec<struct partition *> *partitions, |
| vec<ddr_p> *alias_ddrs) |
| { |
| unsigned i; |
| struct partition *partition, *a; |
| |
| if (partitions->length () == 1 |
| || alias_ddrs->length () > 0) |
| return; |
| |
| unsigned num_builtin = 0, num_normal = 0, num_partial_memset = 0; |
| bool same_type_p = true; |
| enum partition_type type = ((*partitions)[0])->type; |
| for (i = 0; partitions->iterate (i, &partition); ++i) |
| { |
| same_type_p &= (type == partition->type); |
| if (partition_builtin_p (partition)) |
| { |
| num_builtin++; |
| continue; |
| } |
| num_normal++; |
| if (partition->kind == PKIND_PARTIAL_MEMSET) |
| num_partial_memset++; |
| } |
| |
| /* Don't distribute current loop into too many loops given we don't have |
| memory stream cost model. Be even more conservative in case of loop |
| nest distribution. */ |
| if ((same_type_p && num_builtin == 0 |
| && (loop->inner == NULL || num_normal != 2 || num_partial_memset != 1)) |
| || (loop->inner != NULL |
| && i >= NUM_PARTITION_THRESHOLD && num_normal > 1) |
| || (loop->inner == NULL |
| && i >= NUM_PARTITION_THRESHOLD && num_normal > num_builtin)) |
| { |
| a = (*partitions)[0]; |
| for (i = 1; partitions->iterate (i, &partition); ++i) |
| { |
| partition_merge_into (NULL, a, partition, FUSE_FINALIZE); |
| partition_free (partition); |
| } |
| partitions->truncate (1); |
| } |
| |
| /* Fuse memset builtins if possible. */ |
| if (partitions->length () > 1) |
| fuse_memset_builtins (partitions); |
| } |
| |
| /* Distributes the code from LOOP in such a way that producer statements |
| are placed before consumer statements. Tries to separate only the |
| statements from STMTS into separate loops. Returns the number of |
| distributed loops. Set NB_CALLS to number of generated builtin calls. |
| Set *DESTROY_P to whether LOOP needs to be destroyed. */ |
| |
| static int |
| distribute_loop (struct loop *loop, vec<gimple *> stmts, |
| control_dependences *cd, int *nb_calls, bool *destroy_p) |
| { |
| ddrs_table = new hash_table<ddr_hasher> (389); |
| struct graph *rdg; |
| partition *partition; |
| bool any_builtin; |
| int i, nbp; |
| |
| *destroy_p = false; |
| *nb_calls = 0; |
| loop_nest.create (0); |
| if (!find_loop_nest (loop, &loop_nest)) |
| { |
| loop_nest.release (); |
| delete ddrs_table; |
| return 0; |
| } |
| |
| datarefs_vec.create (20); |
| rdg = build_rdg (loop, cd); |
| if (!rdg) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, |
| "Loop %d not distributed: failed to build the RDG.\n", |
| loop->num); |
| |
| loop_nest.release (); |
| free_data_refs (datarefs_vec); |
| delete ddrs_table; |
| return 0; |
| } |
| |
| if (datarefs_vec.length () > MAX_DATAREFS_NUM) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, |
| "Loop %d not distributed: too many memory references.\n", |
| loop->num); |
| |
| free_rdg (rdg); |
| loop_nest.release (); |
| free_data_refs (datarefs_vec); |
| delete ddrs_table; |
| return 0; |
| } |
| |
| data_reference_p dref; |
| for (i = 0; datarefs_vec.iterate (i, &dref); ++i) |
| dref->aux = (void *) (uintptr_t) i; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| dump_rdg (dump_file, rdg); |
| |
| auto_vec<struct partition *, 3> partitions; |
| rdg_build_partitions (rdg, stmts, &partitions); |
| |
| auto_vec<ddr_p> alias_ddrs; |
| |
| auto_bitmap stmt_in_all_partitions; |
| bitmap_copy (stmt_in_all_partitions, partitions[0]->stmts); |
| for (i = 1; partitions.iterate (i, &partition); ++i) |
| bitmap_and_into (stmt_in_all_partitions, partitions[i]->stmts); |
| |
| any_builtin = false; |
| FOR_EACH_VEC_ELT (partitions, i, partition) |
| { |
| classify_partition (loop, rdg, partition, stmt_in_all_partitions); |
| any_builtin |= partition_builtin_p (partition); |
| } |
| |
| /* If we are only distributing patterns but did not detect any, |
| simply bail out. */ |
| if (!flag_tree_loop_distribution |
| && !any_builtin) |
| { |
| nbp = 0; |
| goto ldist_done; |
| } |
| |
| /* If we are only distributing patterns fuse all partitions that |
| were not classified as builtins. This also avoids chopping |
| a loop into pieces, separated by builtin calls. That is, we |
| only want no or a single loop body remaining. */ |
| struct partition *into; |
| if (!flag_tree_loop_distribution) |
| { |
| for (i = 0; partitions.iterate (i, &into); ++i) |
| if (!partition_builtin_p (into)) |
| break; |
| for (++i; partitions.iterate (i, &partition); ++i) |
| if (!partition_builtin_p (partition)) |
| { |
| partition_merge_into (NULL, into, partition, FUSE_NON_BUILTIN); |
| partitions.unordered_remove (i); |
| partition_free (partition); |
| i--; |
| } |
| } |
| |
| /* Due to limitations in the transform phase we have to fuse all |
| reduction partitions into the last partition so the existing |
| loop will contain all loop-closed PHI nodes. */ |
| for (i = 0; partitions.iterate (i, &into); ++i) |
| if (partition_reduction_p (into)) |
| break; |
| for (i = i + 1; partitions.iterate (i, &partition); ++i) |
| if (partition_reduction_p (partition)) |
| { |
| partition_merge_into (rdg, into, partition, FUSE_REDUCTION); |
| partitions.unordered_remove (i); |
| partition_free (partition); |
| i--; |
| } |
| |
| /* Apply our simple cost model - fuse partitions with similar |
| memory accesses. */ |
| for (i = 0; partitions.iterate (i, &into); ++i) |
| { |
| bool changed = false; |
| if (partition_builtin_p (into) || into->kind == PKIND_PARTIAL_MEMSET) |
| continue; |
| for (int j = i + 1; |
| partitions.iterate (j, &partition); ++j) |
| { |
| if (share_memory_accesses (rdg, into, partition)) |
| { |
| partition_merge_into (rdg, into, partition, FUSE_SHARE_REF); |
| partitions.unordered_remove (j); |
| partition_free (partition); |
| j--; |
| changed = true; |
| } |
| } |
| /* If we fused 0 1 2 in step 1 to 0,2 1 as 0 and 2 have similar |
| accesses when 1 and 2 have similar accesses but not 0 and 1 |
| then in the next iteration we will fail to consider merging |
| 1 into 0,2. So try again if we did any merging into 0. */ |
| if (changed) |
| i--; |
| } |
| |
| /* Build the partition dependency graph and fuse partitions in strong |
| connected component. */ |
| if (partitions.length () > 1) |
| { |
| /* Don't support loop nest distribution under runtime alias check |
| since it's not likely to enable many vectorization opportunities. */ |
| if (loop->inner) |
| merge_dep_scc_partitions (rdg, &partitions, false); |
| else |
| { |
| merge_dep_scc_partitions (rdg, &partitions, true); |
| if (partitions.length () > 1) |
| break_alias_scc_partitions (rdg, &partitions, &alias_ddrs); |
| } |
| } |
| |
| finalize_partitions (loop, &partitions, &alias_ddrs); |
| |
| nbp = partitions.length (); |
| if (nbp == 0 |
| || (nbp == 1 && !partition_builtin_p (partitions[0])) |
| || (nbp > 1 && partition_contains_all_rw (rdg, partitions))) |
| { |
| nbp = 0; |
| goto ldist_done; |
| } |
| |
| if (version_for_distribution_p (&partitions, &alias_ddrs)) |
| version_loop_by_alias_check (loop, &alias_ddrs); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, |
| "distribute loop <%d> into partitions:\n", loop->num); |
| dump_rdg_partitions (dump_file, partitions); |
| } |
| |
| FOR_EACH_VEC_ELT (partitions, i, partition) |
| { |
| if (partition_builtin_p (partition)) |
| (*nb_calls)++; |
| *destroy_p |= generate_code_for_partition (loop, partition, i < nbp - 1); |
| } |
| |
| ldist_done: |
| loop_nest.release (); |
| free_data_refs (datarefs_vec); |
| for (hash_table<ddr_hasher>::iterator iter = ddrs_table->begin (); |
| iter != ddrs_table->end (); ++iter) |
| { |
| free_dependence_relation (*iter); |
| *iter = NULL; |
| } |
| delete ddrs_table; |
| |
| FOR_EACH_VEC_ELT (partitions, i, partition) |
| partition_free (partition); |
| |
| free_rdg (rdg); |
| return nbp - *nb_calls; |
| } |
| |
| /* Distribute all loops in the current function. */ |
| |
| namespace { |
| |
| const pass_data pass_data_loop_distribution = |
| { |
| GIMPLE_PASS, /* type */ |
| "ldist", /* name */ |
| OPTGROUP_LOOP, /* optinfo_flags */ |
| TV_TREE_LOOP_DISTRIBUTION, /* tv_id */ |
| ( PROP_cfg | PROP_ssa ), /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| 0, /* todo_flags_finish */ |
| }; |
| |
| class pass_loop_distribution : public gimple_opt_pass |
| { |
| public: |
| pass_loop_distribution (gcc::context *ctxt) |
| : gimple_opt_pass (pass_data_loop_distribution, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| virtual bool gate (function *) |
| { |
| return flag_tree_loop_distribution |
| || flag_tree_loop_distribute_patterns; |
| } |
| |
| virtual unsigned int execute (function *); |
| |
| }; // class pass_loop_distribution |
| |
| |
| /* Given LOOP, this function records seed statements for distribution in |
| WORK_LIST. Return false if there is nothing for distribution. */ |
| |
| static bool |
| find_seed_stmts_for_distribution (struct loop *loop, vec<gimple *> *work_list) |
| { |
| basic_block *bbs = get_loop_body_in_dom_order (loop); |
| |
| /* Initialize the worklist with stmts we seed the partitions with. */ |
| for (unsigned i = 0; i < loop->num_nodes; ++i) |
| { |
| for (gphi_iterator gsi = gsi_start_phis (bbs[i]); |
| !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| gphi *phi = gsi.phi (); |
| if (virtual_operand_p (gimple_phi_result (phi))) |
| continue; |
| /* Distribute stmts which have defs that are used outside of |
| the loop. */ |
| if (!stmt_has_scalar_dependences_outside_loop (loop, phi)) |
| continue; |
| work_list->safe_push (phi); |
| } |
| for (gimple_stmt_iterator gsi = gsi_start_bb (bbs[i]); |
| !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| gimple *stmt = gsi_stmt (gsi); |
| |
| /* If there is a stmt with side-effects bail out - we |
| cannot and should not distribute this loop. */ |
| if (gimple_has_side_effects (stmt)) |
| { |
| free (bbs); |
| return false; |
| } |
| |
| /* Distribute stmts which have defs that are used outside of |
| the loop. */ |
| if (stmt_has_scalar_dependences_outside_loop (loop, stmt)) |
| ; |
| /* Otherwise only distribute stores for now. */ |
| else if (!gimple_vdef (stmt)) |
| continue; |
| |
| work_list->safe_push (stmt); |
| } |
| } |
| free (bbs); |
| return work_list->length () > 0; |
| } |
| |
| /* Given innermost LOOP, return the outermost enclosing loop that forms a |
| perfect loop nest. */ |
| |
| static struct loop * |
| prepare_perfect_loop_nest (struct loop *loop) |
| { |
| struct loop *outer = loop_outer (loop); |
| tree niters = number_of_latch_executions (loop); |
| |
| /* TODO: We only support the innermost 3-level loop nest distribution |
| because of compilation time issue for now. This should be relaxed |
| in the future. Note we only allow 3-level loop nest distribution |
| when parallelizing loops. */ |
| while ((loop->inner == NULL |
| || (loop->inner->inner == NULL && flag_tree_parallelize_loops > 1)) |
| && loop_outer (outer) |
| && outer->inner == loop && loop->next == NULL |
| && single_exit (outer) |
| && optimize_loop_for_speed_p (outer) |
| && !chrec_contains_symbols_defined_in_loop (niters, outer->num) |
| && (niters = number_of_latch_executions (outer)) != NULL_TREE |
| && niters != chrec_dont_know) |
| { |
| loop = outer; |
| outer = loop_outer (loop); |
| } |
| |
| return loop; |
| } |
| |
| unsigned int |
| pass_loop_distribution::execute (function *fun) |
| { |
| struct loop *loop; |
| bool changed = false; |
| basic_block bb; |
| control_dependences *cd = NULL; |
| auto_vec<loop_p> loops_to_be_destroyed; |
| |
| if (number_of_loops (fun) <= 1) |
| return 0; |
| |
| /* Compute topological order for basic blocks. Topological order is |
| needed because data dependence is computed for data references in |
| lexicographical order. */ |
| if (bb_top_order_index == NULL) |
| { |
| int rpo_num; |
| int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); |
| |
| bb_top_order_index = XNEWVEC (int, last_basic_block_for_fn (cfun)); |
| bb_top_order_index_size = last_basic_block_for_fn (cfun); |
| rpo_num = pre_and_rev_post_order_compute_fn (cfun, NULL, rpo, true); |
| for (int i = 0; i < rpo_num; i++) |
| bb_top_order_index[rpo[i]] = i; |
| |
| free (rpo); |
| } |
| |
| FOR_ALL_BB_FN (bb, fun) |
| { |
| gimple_stmt_iterator gsi; |
| for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| gimple_set_uid (gsi_stmt (gsi), -1); |
| for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| gimple_set_uid (gsi_stmt (gsi), -1); |
| } |
| |
| /* We can at the moment only distribute non-nested loops, thus restrict |
| walking to innermost loops. */ |
| FOR_EACH_LOOP (loop, LI_ONLY_INNERMOST) |
| { |
| /* Don't distribute multiple exit edges loop, or cold loop. */ |
| if (!single_exit (loop) |
| || !optimize_loop_for_speed_p (loop)) |
| continue; |
| |
| /* Don't distribute loop if niters is unknown. */ |
| tree niters = number_of_latch_executions (loop); |
| if (niters == NULL_TREE || niters == chrec_dont_know) |
| continue; |
| |
| /* Get the perfect loop nest for distribution. */ |
| loop = prepare_perfect_loop_nest (loop); |
| for (; loop; loop = loop->inner) |
| { |
| auto_vec<gimple *> work_list; |
| if (!find_seed_stmts_for_distribution (loop, &work_list)) |
| break; |
| |
| const char *str = loop->inner ? " nest" : ""; |
| location_t loc = find_loop_location (loop); |
| if (!cd) |
| { |
| calculate_dominance_info (CDI_DOMINATORS); |
| calculate_dominance_info (CDI_POST_DOMINATORS); |
| cd = new control_dependences (); |
| free_dominance_info (CDI_POST_DOMINATORS); |
| } |
| |
| bool destroy_p; |
| int nb_generated_loops, nb_generated_calls; |
| nb_generated_loops = distribute_loop (loop, work_list, cd, |
| &nb_generated_calls, |
| &destroy_p); |
| if (destroy_p) |
| loops_to_be_destroyed.safe_push (loop); |
| |
| if (nb_generated_loops + nb_generated_calls > 0) |
| { |
| changed = true; |
| dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, |
| loc, "Loop%s %d distributed: split to %d loops " |
| "and %d library calls.\n", str, loop->num, |
| nb_generated_loops, nb_generated_calls); |
| |
| break; |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Loop%s %d not distributed.\n", str, loop->num); |
| } |
| } |
| |
|