/* Loop distribution.
- Copyright (C) 2006-2013 Free Software Foundation, Inc.
+ Copyright (C) 2006-2020 Free Software Foundation, Inc.
Contributed by Georges-Andre Silber <Georges-Andre.Silber@ensmp.fr>
and Sebastian Pop <sebastian.pop@amd.com>.
| D(I) = A(I-1)*E
|ENDDO
- This pass uses an RDG, Reduced Dependence Graph built on top of the
- data dependence relations. The RDG is then topologically sorted to
- obtain a map of information producers/consumers based on which it
- generates the new loops. */
+ 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"
#include "system.h"
#include "coretypes.h"
+#include "backend.h"
#include "tree.h"
-#include "basic-block.h"
-#include "tree-ssa-alias.h"
-#include "internal-fn.h"
-#include "gimple-expr.h"
-#include "is-a.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 "gimple-ssa.h"
#include "tree-cfg.h"
-#include "tree-phinodes.h"
-#include "ssa-iterators.h"
-#include "stringpool.h"
-#include "tree-ssanames.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-chrec.h"
-#include "tree-data-ref.h"
#include "tree-scalar-evolution.h"
-#include "tree-pass.h"
-#include "gimple-pretty-print.h"
#include "tree-vectorizer.h"
+#include "tree-eh.h"
+#include "gimple-fold.h"
+
+
+#define MAX_DATAREFS_NUM \
+ ((unsigned) 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));
+}
+
+#define DR_INDEX(dr) ((uintptr_t) (dr)->aux)
+
/* A Reduced Dependence Graph (RDG) vertex representing a statement. */
-typedef struct rdg_vertex
+struct rdg_vertex
{
/* The statement represented by this vertex. */
- gimple stmt;
+ gimple *stmt;
/* Vector of data-references in this statement. */
vec<data_reference_p> datarefs;
/* True when the statement contains a read from memory. */
bool has_mem_reads;
-} *rdg_vertex_p;
+};
#define RDGV_STMT(V) ((struct rdg_vertex *) ((V)->data))->stmt
#define RDGV_DATAREFS(V) ((struct rdg_vertex *) ((V)->data))->datarefs
/* Dependence information attached to an edge of the RDG. */
-typedef struct rdg_edge
+struct rdg_edge
{
/* Type of the dependence. */
enum rdg_dep_type type;
-} *rdg_edge_p;
+};
#define RDGE_TYPE(E) ((struct rdg_edge *) ((E)->data))->type
+/* 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;
+ location_t loc;
+ enum partition_kind kind;
+ enum partition_type type;
+ /* Data references in the partition. */
+ bitmap datarefs;
+ /* Information of builtin parition. */
+ struct builtin_info *builtin;
+};
+
+/* 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"};
+
+
/* Dump vertex I in RDG to FILE. */
static void
dot_rdg (struct graph *rdg)
{
/* When debugging, you may want to enable the following code. */
-#if 1
+#ifdef HAVE_POPEN
FILE *file = popen ("dot -Tx11", "w");
if (!file)
return;
/* Returns the index of STMT in RDG. */
static int
-rdg_vertex_for_stmt (struct graph *rdg ATTRIBUTE_UNUSED, gimple stmt)
+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);
EXECUTE_IF_SET_IN_BITMAP (cd->get_edges_dependent_on (bb->index),
0, edge_n, bi)
{
- basic_block cond_bb = cd->get_edge (edge_n)->src;
- gimple stmt = last_stmt (cond_bb);
+ 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;
/* Creates the edges of the reduced dependence graph RDG. */
static void
-create_rdg_cd_edges (struct graph *rdg, control_dependences *cd)
+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);
+ 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
}
}
-/* 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,
- vec<data_reference_p> *datarefs)
+class loop_distribution
+{
+ private:
+ /* The loop (nest) to be distributed. */
+ vec<loop_p> loop_nest;
+
+ /* Vector of data references in the loop to be distributed. */
+ vec<data_reference_p> datarefs_vec;
+
+ /* If there is nonaddressable data reference in above vector. */
+ bool has_nonaddressable_dataref_p;
+
+ /* Store index of data reference in aux field. */
+
+ /* Hash table for data dependence relation in the loop to be distributed. */
+ hash_table<ddr_hasher> *ddrs_table;
+
+ /* Array mapping basic block's index to its topological order. */
+ int *bb_top_order_index;
+ /* And size of the array. */
+ int bb_top_order_index_size;
+
+ /* Build the vertices of the reduced dependence graph RDG. Return false
+ if that failed. */
+ bool create_rdg_vertices (struct graph *rdg, vec<gimple *> stmts, loop_p loop);
+
+ /* 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. */
+ void stmts_from_loop (class loop *loop, vec<gimple *> *stmts);
+
+
+ /* 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. */
+ struct graph * build_rdg (class loop *loop, control_dependences *cd);
+
+/* Merge PARTITION into the partition DEST. RDG is the reduced dependence
+ graph and we update type for result partition if it is non-NULL. */
+ void partition_merge_into (struct graph *rdg,
+ partition *dest, partition *partition,
+ enum fuse_type ft);
+
+
+ /* 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. */
+ data_dependence_relation * get_data_dependence (struct graph *rdg,
+ data_reference_p a,
+ data_reference_p b);
+
+
+ /* 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. */
+ bool data_dep_in_cycle_p (struct graph *rdg, data_reference_p dr1,
+ data_reference_p dr2);
+
+
+ /* Given reduced dependence graph RDG, PARTITION1 and PARTITION2, update
+ PARTITION1's type after merging PARTITION2 into PARTITION1. */
+ void update_type_for_merge (struct graph *rdg,
+ partition *partition1, partition *partition2);
+
+
+ /* Returns a partition with all the statements needed for computing
+ the vertex V of the RDG, also including the loop exit conditions. */
+ partition *build_rdg_partition_for_vertex (struct graph *rdg, int v);
+
+ /* Given data references DST_DR and SRC_DR in loop nest LOOP and RDG, classify
+ if it forms builtin memcpy or memmove call. */
+ void classify_builtin_ldst (loop_p loop, struct graph *rdg, partition *partition,
+ data_reference_p dst_dr, data_reference_p src_dr);
+
+ /* 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.
+ Returns true if there is a reduction in all partitions and we
+ possibly did not mark PARTITION as having one for this reason. */
+
+ bool
+ classify_partition (loop_p loop,
+ struct graph *rdg, partition *partition,
+ bitmap stmt_in_all_partitions);
+
+
+ /* Returns true when PARTITION1 and PARTITION2 access the same memory
+ object in RDG. */
+ bool share_memory_accesses (struct graph *rdg,
+ partition *partition1, partition *partition2);
+
+ /* 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. */
+ void rdg_build_partitions (struct graph *rdg,
+ vec<gimple *> starting_stmts,
+ vec<partition *> *partitions);
+
+ /* 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. */
+ int pg_add_dependence_edges (struct graph *rdg, int dir, bitmap drs1,
+ bitmap drs2, vec<ddr_p> *alias_ddrs);
+
+
+ /* 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. */
+ struct graph *build_partition_graph (struct graph *rdg,
+ vec<struct partition *> *partitions,
+ bool ignore_alias_p);
+
+ /* 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. */
+ void merge_dep_scc_partitions (struct graph *rdg, vec<struct partition *>
+ *partitions, bool ignore_alias_p);
+
+/* 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. */
+ void break_alias_scc_partitions (struct graph *rdg, vec<struct partition *>
+ *partitions, vec<ddr_p> *alias_ddrs);
+
+
+ /* Fuse PARTITIONS of LOOP if necessary before finalizing distribution.
+ ALIAS_DDRS contains ddrs which need runtime alias check. */
+ void finalize_partitions (class loop *loop, vec<struct partition *>
+ *partitions, vec<ddr_p> *alias_ddrs);
+
+ /* 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. */
+ int distribute_loop (class loop *loop, vec<gimple *> stmts,
+ control_dependences *cd, int *nb_calls, bool *destroy_p,
+ bool only_patterns_p);
+
+ /* Compute topological order for basic blocks. Topological order is
+ needed because data dependence is computed for data references in
+ lexicographical order. */
+ void bb_top_order_init (void);
+
+ void bb_top_order_destroy (void);
+
+ public:
+
+ /* Getter for bb_top_order. */
+
+ inline int get_bb_top_order_index_size (void)
+ {
+ return bb_top_order_index_size;
+ }
+
+ inline int get_bb_top_order_index (int i)
+ {
+ return bb_top_order_index[i];
+ }
+
+ unsigned int execute (function *fun);
+};
+
+
+/* If X has a smaller topological sort number than Y, returns -1;
+ if greater, returns 1. */
+static int
+bb_top_order_cmp_r (const void *x, const void *y, void *loop)
+{
+ loop_distribution *_loop =
+ (loop_distribution *) loop;
+
+ basic_block bb1 = *(const basic_block *) x;
+ basic_block bb2 = *(const basic_block *) y;
+
+ int bb_top_order_index_size = _loop->get_bb_top_order_index_size ();
+
+ gcc_assert (bb1->index < bb_top_order_index_size
+ && bb2->index < bb_top_order_index_size);
+ gcc_assert (bb1 == bb2
+ || _loop->get_bb_top_order_index(bb1->index)
+ != _loop->get_bb_top_order_index(bb2->index));
+
+ return (_loop->get_bb_top_order_index(bb1->index) -
+ _loop->get_bb_top_order_index(bb2->index));
+}
+
+bool
+loop_distribution::create_rdg_vertices (struct graph *rdg, vec<gimple *> stmts,
+ loop_p loop)
{
int i;
- gimple stmt;
+ gimple *stmt;
FOR_EACH_VEC_ELT (stmts, i, stmt)
{
if (gimple_code (stmt) == GIMPLE_PHI)
continue;
- unsigned drp = datarefs->length ();
- if (!find_data_references_in_stmt (loop, stmt, datarefs))
+ unsigned drp = datarefs_vec.length ();
+ if (!find_data_references_in_stmt (loop, stmt, &datarefs_vec))
return false;
- for (unsigned j = drp; j < datarefs->length (); ++j)
+ for (unsigned j = drp; j < datarefs_vec.length (); ++j)
{
- data_reference_p dr = (*datarefs)[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);
+ has_nonaddressable_dataref_p |= may_be_nonaddressable_p (dr->ref);
}
}
return true;
}
-/* Initialize STMTS with all the statements of LOOP. The order in
- which we discover statements is important as
- 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)
+void
+loop_distribution::stmts_from_loop (class loop *loop, vec<gimple *> *stmts)
{
unsigned int i;
- basic_block *bbs = get_loop_body_in_dom_order (loop);
+ basic_block *bbs = get_loop_body_in_custom_order (loop, this, bb_top_order_cmp_r);
for (i = 0; i < loop->num_nodes; i++)
{
basic_block bb = bbs[i];
- gimple_stmt_iterator bsi;
- gimple stmt;
- for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
- if (!virtual_operand_p (gimple_phi_result (gsi_stmt (bsi))))
- stmts->safe_push (gsi_stmt (bsi));
+ 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 (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+ for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi);
+ gsi_next (&bsi))
{
- stmt = gsi_stmt (bsi);
+ gimple *stmt = gsi_stmt (bsi);
if (gimple_code (stmt) != GIMPLE_LABEL && !is_gimple_debug (stmt))
stmts->safe_push (stmt);
}
if (v->data)
{
gimple_set_uid (RDGV_STMT (v), -1);
- free_data_refs (RDGV_DATAREFS (v));
+ (RDGV_DATAREFS (v)).release ();
free (v->data);
}
}
free_graph (rdg);
}
-/* Build the Reduced Dependence Graph (RDG) with one vertex per
- statement of the loop nest LOOP_NEST, and one edge per data dependence or
- scalar dependence. */
-
-static struct graph *
-build_rdg (vec<loop_p> loop_nest, control_dependences *cd)
+struct graph *
+loop_distribution::build_rdg (class loop *loop, control_dependences *cd)
{
struct graph *rdg;
- vec<data_reference_p> datarefs;
/* Create the RDG vertices from the stmts of the loop nest. */
- auto_vec<gimple, 10> stmts;
- stmts_from_loop (loop_nest[0], &stmts);
+ auto_vec<gimple *, 10> stmts;
+ stmts_from_loop (loop, &stmts);
rdg = new_graph (stmts.length ());
- datarefs.create (10);
- if (!create_rdg_vertices (rdg, stmts, loop_nest[0], &datarefs))
+ if (!create_rdg_vertices (rdg, stmts, loop))
{
- datarefs.release ();
free_rdg (rdg);
return NULL;
}
create_rdg_flow_edges (rdg);
if (cd)
- create_rdg_cd_edges (rdg, cd);
-
- datarefs.release ();
+ create_rdg_cd_edges (rdg, cd, loop);
return rdg;
}
-
-enum partition_kind {
- PKIND_NORMAL, PKIND_MEMSET, PKIND_MEMCPY
-};
-
-typedef struct partition_s
-{
- bitmap stmts;
- bitmap loops;
- bool reduction_p;
- enum partition_kind kind;
- /* data-references a kind != PKIND_NORMAL partition is about. */
- data_reference_p main_dr;
- data_reference_p secondary_dr;
- tree niter;
- bool plus_one;
-} *partition_t;
-
-
/* Allocate and initialize a partition from BITMAP. */
-static partition_t
-partition_alloc (bitmap stmts, bitmap loops)
+static partition *
+partition_alloc (void)
{
- partition_t partition = XCNEW (struct partition_s);
- partition->stmts = stmts ? stmts : BITMAP_ALLOC (NULL);
- partition->loops = loops ? loops : BITMAP_ALLOC (NULL);
+ partition *partition = XCNEW (struct partition);
+ partition->stmts = BITMAP_ALLOC (NULL);
partition->reduction_p = false;
+ partition->loc = UNKNOWN_LOCATION;
partition->kind = PKIND_NORMAL;
+ partition->type = PTYPE_PARALLEL;
+ partition->datarefs = BITMAP_ALLOC (NULL);
return partition;
}
/* Free PARTITION. */
static void
-partition_free (partition_t partition)
+partition_free (partition *partition)
{
BITMAP_FREE (partition->stmts);
- BITMAP_FREE (partition->loops);
+ 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_t partition)
+partition_builtin_p (partition *partition)
{
- return partition->kind != PKIND_NORMAL;
+ return partition->kind > PKIND_PARTIAL_MEMSET;
}
/* Returns true if the partition contains a reduction. */
static bool
-partition_reduction_p (partition_t partition)
+partition_reduction_p (partition *partition)
{
return partition->reduction_p;
}
-/* Merge PARTITION into the partition DEST. */
-
-static void
-partition_merge_into (partition_t dest, partition_t partition)
+void
+loop_distribution::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);
}
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def)
{
- gimple use_stmt = USE_STMT (use_p);
- if (!is_gimple_debug (use_stmt)
- && loop != loop_containing_stmt (use_stmt))
+ 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;
}
loop LOOP. */
static bool
-stmt_has_scalar_dependences_outside_loop (loop_p loop, gimple stmt)
+stmt_has_scalar_dependences_outside_loop (loop_p loop, gimple *stmt)
{
def_operand_p def_p;
ssa_op_iter op_iter;
/* Return a copy of LOOP placed before LOOP. */
-static struct loop *
-copy_loop_before (struct loop *loop)
+static class loop *
+copy_loop_before (class loop *loop)
{
- struct loop *res;
+ class loop *res;
edge preheader = loop_preheader_edge (loop);
initialize_original_copy_tables ();
/* Creates an empty basic block after LOOP. */
static void
-create_bb_after_loop (struct loop *loop)
+create_bb_after_loop (class loop *loop)
{
edge exit = single_exit (loop);
basic blocks of a loop are taken in dom order. */
static void
-generate_loops_for_partition (struct loop *loop, partition_t partition,
+generate_loops_for_partition (class loop *loop, partition *partition,
bool copy_p)
{
unsigned i;
- gimple_stmt_iterator bsi;
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_STMTS)
+ if (MAY_HAVE_DEBUG_BIND_STMTS)
for (i = 0; i < loop->num_nodes; i++)
{
basic_block bb = bbs[i];
- for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+ for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi);
+ gsi_next (&bsi))
{
- gimple phi = gsi_stmt (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 (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+ for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
{
- gimple stmt = gsi_stmt (bsi);
+ gimple *stmt = gsi_stmt (bsi);
if (gimple_code (stmt) != GIMPLE_LABEL
&& !is_gimple_debug (stmt)
&& !bitmap_bit_p (partition->stmts, gimple_uid (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 (bsi = gsi_start_phis (bb); !gsi_end_p (bsi);)
+ for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi);)
{
- gimple phi = gsi_stmt (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);
gsi_next (&bsi);
}
- for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi);)
+ for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi);)
{
- gimple stmt = gsi_stmt (bsi);
+ gimple *stmt = gsi_stmt (bsi);
if (gimple_code (stmt) != GIMPLE_LABEL
&& !is_gimple_debug (stmt)
&& !bitmap_bit_p (partition->stmts, gimple_uid (stmt)))
{
- /* Choose an arbitrary path through the empty CFG part
- that this unnecessary control stmt controls. */
- if (gimple_code (stmt) == GIMPLE_COND)
+ /* 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))
{
- gimple_cond_make_false (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
- (stmt, CASE_LOW (gimple_switch_label (stmt, 1)));
+ (switch_stmt, CASE_LOW (gimple_switch_label (switch_stmt, 1)));
update_stmt (stmt);
}
else
free (bbs);
}
-/* Build the size argument for a memory operation call. */
-
-static tree
-build_size_arg_loc (location_t loc, data_reference_p dr, tree nb_iter,
- bool plus_one)
-{
- tree size = fold_convert_loc (loc, sizetype, nb_iter);
- if (plus_one)
- size = size_binop (PLUS_EXPR, size, size_one_node);
- size = fold_build2_loc (loc, MULT_EXPR, sizetype, size,
- TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
- size = fold_convert_loc (loc, size_type_node, size);
- return size;
-}
-
-/* Build an address argument for a memory operation call. */
-
-static tree
-build_addr_arg_loc (location_t loc, data_reference_p dr, tree nb_bytes)
-{
- tree addr_base;
-
- addr_base = size_binop_loc (loc, PLUS_EXPR, DR_OFFSET (dr), DR_INIT (dr));
- addr_base = fold_convert_loc (loc, sizetype, addr_base);
-
- /* Test for a negative stride, iterating over every element. */
- if (tree_int_cst_sgn (DR_STEP (dr)) == -1)
- {
- addr_base = size_binop_loc (loc, MINUS_EXPR, addr_base,
- fold_convert_loc (loc, sizetype, nb_bytes));
- addr_base = size_binop_loc (loc, PLUS_EXPR, addr_base,
- TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
- }
-
- return fold_build_pointer_plus_loc (loc, DR_BASE_ADDRESS (dr), addr_base);
-}
-
/* 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
int i, len;
if (integer_zerop (val)
- || real_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;
/* Generate a call to memset for PARTITION in LOOP. */
static void
-generate_memset_builtin (struct loop *loop, partition_t partition)
+generate_memset_builtin (class loop *loop, partition *partition)
{
gimple_stmt_iterator gsi;
- gimple stmt, fn_call;
tree mem, fn, nb_bytes;
- location_t loc;
tree val;
-
- stmt = DR_STMT (partition->main_dr);
- loc = gimple_location (stmt);
+ 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 = build_size_arg_loc (loc, partition->main_dr, partition->niter,
- partition->plus_one);
+ nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
- mem = build_addr_arg_loc (loc, partition->main_dr, nb_bytes);
+ mem = rewrite_to_non_trapping_overflow (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 (stmt);
+ 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);
val = fold_convert (integer_type_node, val);
else if (!useless_type_conversion_p (integer_type_node, TREE_TYPE (val)))
{
- gimple cstmt;
- tree tem = make_ssa_name (integer_type_node, NULL);
- cstmt = gimple_build_assign_with_ops (NOP_EXPR, tem, val, NULL_TREE);
+ 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);
+ gimple_set_location (fn_call, partition->loc);
gsi_insert_after (&gsi, fn_call, GSI_CONTINUE_LINKING);
+ fold_stmt (&gsi);
if (dump_file && (dump_flags & TDF_DETAILS))
{
/* Generate a call to memcpy for PARTITION in LOOP. */
static void
-generate_memcpy_builtin (struct loop *loop, partition_t partition)
+generate_memcpy_builtin (class loop *loop, partition *partition)
{
gimple_stmt_iterator gsi;
- gimple stmt, fn_call;
+ gimple *fn_call;
tree dest, src, fn, nb_bytes;
- location_t loc;
enum built_in_function kind;
-
- stmt = DR_STMT (partition->main_dr);
- loc = gimple_location (stmt);
+ 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 = build_size_arg_loc (loc, partition->main_dr, partition->niter,
- partition->plus_one);
+ nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
- dest = build_addr_arg_loc (loc, partition->main_dr, nb_bytes);
- src = build_addr_arg_loc (loc, partition->secondary_dr, nb_bytes);
- if (ptr_derefs_may_alias_p (dest, src))
- kind = BUILT_IN_MEMMOVE;
- else
+ dest = rewrite_to_non_trapping_overflow (builtin->dst_base);
+ src = rewrite_to_non_trapping_overflow (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);
false, GSI_CONTINUE_LINKING);
fn = build_fold_addr_expr (builtin_decl_implicit (kind));
fn_call = gimple_build_call (fn, 3, dest, src, nb_bytes);
+ gimple_set_location (fn_call, partition->loc);
gsi_insert_after (&gsi, fn_call, GSI_CONTINUE_LINKING);
+ fold_stmt (&gsi);
if (dump_file && (dump_flags & TDF_DETAILS))
{
/* Remove and destroy the loop LOOP. */
static void
-destroy_loop (struct loop *loop)
+destroy_loop (class loop *loop)
{
unsigned nbbs = loop->num_nodes;
edge exit = single_exit (loop);
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);
-
- for (i = 0; i < nbbs; i++)
+ gimple_stmt_iterator dst_gsi = gsi_after_labels (exit->dest);
+ bool safe_p = single_pred_p (exit->dest);
+ for (unsigned i = 0; i < nbbs; ++i)
{
/* 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. */
- gimple_stmt_iterator gsi;
- for (gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+ for (gphi_iterator gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi);
+ gsi_next (&gsi))
{
- gimple phi = gsi_stmt (gsi);
+ gphi *phi = gsi.phi ();
if (virtual_operand_p (gimple_phi_result (phi)))
mark_virtual_phi_result_for_renaming (phi);
}
- for (gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+ for (gimple_stmt_iterator gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi);)
{
- gimple stmt = gsi_stmt (gsi);
+ gimple *stmt = gsi_stmt (gsi);
tree vdef = gimple_vdef (stmt);
if (vdef && TREE_CODE (vdef) == SSA_NAME)
mark_virtual_operand_for_renaming (vdef);
+ /* Also move and eventually reset debug stmts. We can leave
+ constant values in place in case the stmt dominates the exit.
+ ??? Non-constant values from the last iteration can be
+ replaced with final values if we can compute them. */
+ if (gimple_debug_bind_p (stmt))
+ {
+ tree val = gimple_debug_bind_get_value (stmt);
+ gsi_move_before (&gsi, &dst_gsi);
+ if (val
+ && (!safe_p
+ || !is_gimple_min_invariant (val)
+ || !dominated_by_p (CDI_DOMINATORS, exit->src, bbs[i])))
+ {
+ gimple_debug_bind_reset_value (stmt);
+ update_stmt (stmt);
+ }
+ }
+ else
+ gsi_next (&gsi);
}
+ }
+
+ 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
+ {
+ --i;
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. */
+/* Generates code for PARTITION. Return whether LOOP needs to be destroyed. */
-static void
-generate_code_for_partition (struct loop *loop,
- partition_t partition, bool copy_p)
+static bool
+generate_code_for_partition (class 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;
+ return false;
case PKIND_MEMSET:
generate_memset_builtin (loop, partition);
break;
case PKIND_MEMCPY:
+ case PKIND_MEMMOVE:
generate_memcpy_builtin (loop, partition);
break;
/* 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)
- destroy_loop (loop);
+ return true;
+ return false;
+}
+
+data_dependence_relation *
+loop_distribution::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;
+}
+
+bool
+loop_distribution::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;
}
+void
+loop_distribution::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;
-/* Returns a partition with all the statements needed for computing
- the vertex V of the RDG, also including the loop exit conditions. */
+ /* 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;
+ }
+ }
+ }
+}
-static partition_t
-build_rdg_partition_for_vertex (struct graph *rdg, int v)
+partition *
+loop_distribution::build_rdg_partition_for_vertex (struct graph *rdg, int v)
{
- partition_t partition = partition_alloc (NULL, NULL);
+ partition *partition = partition_alloc ();
auto_vec<int, 3> nodes;
- unsigned i;
+ 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);
- bitmap_set_bit (partition->loops,
- loop_containing_stmt (RDG_STMT (rdg, x))->num);
- }
- return partition;
-}
+ for (j = 0; RDG_DATAREFS (rdg, x).iterate (j, &dr); ++j)
+ {
+ unsigned idx = (unsigned) DR_INDEX (dr);
+ gcc_assert (idx < datarefs_vec.length ());
-/* Classifies the builtin kind we can generate for PARTITION of RDG and LOOP.
- For the moment we detect only the memset zero pattern. */
+ /* 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;
-static void
-classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
-{
- bitmap_iterator bi;
- unsigned i;
- tree nb_iter;
- data_reference_p single_load, single_store;
- bool volatiles_p = false;
- bool plus_one = false;
+ bitmap_set_bit (partition->datarefs, idx);
+ }
+ }
- partition->kind = PKIND_NORMAL;
- partition->main_dr = NULL;
- partition->secondary_dr = NULL;
- partition->niter = NULL_TREE;
- partition->plus_one = false;
+ if (partition->type == PTYPE_SEQUENTIAL)
+ return partition;
- EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi)
- {
- gimple stmt = RDG_STMT (rdg, i);
+ /* Further check if any data dependence prevents us from executing the
+ partition parallelly. */
+ update_type_for_merge (rdg, partition, partition);
- if (gimple_has_volatile_ops (stmt))
- volatiles_p = true;
+ return partition;
+}
- /* If the stmt has uses outside of the loop mark it as reduction. */
- if (stmt_has_scalar_dependences_outside_loop (loop, stmt))
- {
- partition->reduction_p = true;
- return;
- }
- }
+/* 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. */
- /* Perform general partition disqualification for builtins. */
- if (volatiles_p
- || !flag_tree_loop_distribute_patterns)
- return;
+static bool
+find_single_drs (class 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;
- /* Detect memset and memcpy. */
- single_load = NULL;
- single_store = NULL;
EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi)
{
- gimple stmt = RDG_STMT (rdg, i);
+ gimple *stmt = RDG_STMT (rdg, i);
data_reference_p dr;
- unsigned j;
if (gimple_code (stmt) == GIMPLE_PHI)
continue;
/* Otherwise just regular loads/stores. */
if (!gimple_assign_single_p (stmt))
- return;
+ return false;
/* But exactly one store and/or load. */
- for (j = 0; RDG_DATAREFS (rdg, i).iterate (j, &dr); ++j)
+ 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_load != NULL)
- return;
- single_load = dr;
+ if (single_ld != NULL)
+ return false;
+ single_ld = dr;
}
else
{
- if (single_store != NULL)
- return;
- single_store = dr;
+ if (single_st != NULL)
+ return false;
+ single_st = dr;
}
}
}
- if (!single_store)
- return;
+ if (!single_st)
+ return false;
- nb_iter = number_of_latch_executions (loop);
- if (!nb_iter || nb_iter == chrec_dont_know)
- return;
- if (dominated_by_p (CDI_DOMINATORS, single_exit (loop)->src,
- gimple_bb (DR_STMT (single_store))))
- plus_one = true;
-
- if (single_store && !single_load)
- {
- gimple stmt = DR_STMT (single_store);
- tree 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;
- if (!adjacent_dr_p (single_store)
- || !dominated_by_p (CDI_DOMINATORS,
- loop->latch, gimple_bb (stmt)))
- return;
- partition->kind = PKIND_MEMSET;
- partition->main_dr = single_store;
- partition->niter = nb_iter;
- partition->plus_one = plus_one;
- }
- else if (single_store && single_load)
+ /* 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_store);
- gimple load = DR_STMT (single_load);
+ 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;
- if (!adjacent_dr_p (single_store)
- || !adjacent_dr_p (single_load)
- || !operand_equal_p (DR_STEP (single_store),
- DR_STEP (single_load), 0)
- || !dominated_by_p (CDI_DOMINATORS,
- loop->latch, gimple_bb (store)))
- return;
- /* Now check that if there is a dependence this dependence is
- of a suitable form for memmove. */
- vec<loop_p> loops = vNULL;
- ddr_p ddr;
- loops.safe_push (loop);
- ddr = initialize_data_dependence_relation (single_load, single_store,
- loops);
- compute_affine_dependence (ddr, loop);
- if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
- {
- free_dependence_relation (ddr);
- loops.release ();
- return;
- }
- if (DDR_ARE_DEPENDENT (ddr) != chrec_known)
- {
- if (DDR_NUM_DIST_VECTS (ddr) == 0)
- {
- free_dependence_relation (ddr);
- loops.release ();
- return;
- }
- lambda_vector dist_v;
- FOR_EACH_VEC_ELT (DDR_DIST_VECTS (ddr), i, dist_v)
- {
- int dist = dist_v[index_in_loop_nest (loop->num,
- DDR_LOOP_NEST (ddr))];
- if (dist > 0 && !DDR_REVERSED_P (ddr))
- {
- free_dependence_relation (ddr);
- loops.release ();
- return;
- }
- }
- }
- free_dependence_relation (ddr);
- loops.release ();
- partition->kind = PKIND_MEMCPY;
- partition->main_dr = single_store;
- partition->secondary_dr = single_load;
- partition->niter = nb_iter;
- partition->plus_one = plus_one;
+ 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;
}
-/* For a data reference REF, return the declaration of its base
- address or NULL_TREE if the base is not determined. */
+/* 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:
-static tree
-ref_base_address (data_reference_p dr)
-{
- tree base_address = DR_BASE_ADDRESS (dr);
- if (base_address
- && TREE_CODE (base_address) == ADDR_EXPR)
- return TREE_OPERAND (base_address, 0);
+ 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 base_address;
-}
+ Return 1 if we can prove the equality at the innermost loop, but not all
+ level loops. In this case, no information is recorded.
-/* Returns true when PARTITION1 and PARTITION2 have similar memory
- accesses in RDG. */
+ Return 0 if no equality can be proven at any level loops. */
-static bool
-similar_memory_accesses (struct graph *rdg, partition_t partition1,
- partition_t partition2)
+static int
+compute_access_range (loop_p loop_nest, data_reference_p dr, tree *base,
+ tree *size, vec<tree> *steps = NULL)
{
- unsigned i, j, k, l;
- bitmap_iterator bi, bj;
- data_reference_p ref1, ref2;
+ location_t loc = gimple_location (DR_STMT (dr));
+ basic_block bb = gimple_bb (DR_STMT (dr));
+ class 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. */
+
+void
+loop_distribution::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;
+}
+
+bool
+loop_distribution::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;
+ else
+ has_reduction = true;
+ }
+ }
+
+ /* Simple workaround to prevent classifying the partition as builtin
+ if it contains any use outside of loop. For the case where all
+ partitions have the reduction this simple workaround is delayed
+ to only affect the last partition. */
+ if (partition->reduction_p)
+ return has_reduction;
+
+ /* Perform general partition disqualification for builtins. */
+ if (volatiles_p
+ || !flag_tree_loop_distribute_patterns)
+ return has_reduction;
+
+ /* Find single load/store data references for builtin partition. */
+ if (!find_single_drs (loop, rdg, partition, &single_st, &single_ld))
+ return has_reduction;
+
+ partition->loc = gimple_location (DR_STMT (single_st));
+
+ /* 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);
+ return has_reduction;
+}
+
+bool
+loop_distribution::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
|| RDG_MEM_READS_STMT (rdg, i))
return true;
- /* Then check all data-references against each other. */
- EXECUTE_IF_SET_IN_BITMAP (partition1->stmts, 0, i, bi)
- if (RDG_MEM_WRITE_STMT (rdg, i)
- || RDG_MEM_READS_STMT (rdg, i))
- EXECUTE_IF_SET_IN_BITMAP (partition2->stmts, 0, j, bj)
- if (RDG_MEM_WRITE_STMT (rdg, j)
- || RDG_MEM_READS_STMT (rdg, j))
- {
- FOR_EACH_VEC_ELT (RDG_DATAREFS (rdg, i), k, ref1)
- {
- tree base1 = ref_base_address (ref1);
- if (base1)
- FOR_EACH_VEC_ELT (RDG_DATAREFS (rdg, j), l, ref2)
- if (base1 == ref_base_address (ref2))
- 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;
}
-/* Aggregate several components into a useful partition that is
- registered in the PARTITIONS vector. Partitions will be
- distributed in different loops. */
+/* 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_t> *partitions)
+void
+loop_distribution::rdg_build_partitions (struct graph *rdg,
+ vec<gimple *> starting_stmts,
+ vec<partition *> *partitions)
{
- bitmap processed = BITMAP_ALLOC (NULL);
+ auto_bitmap processed;
int i;
- gimple stmt;
+ gimple *stmt;
FOR_EACH_VEC_ELT (starting_stmts, i, stmt)
{
if (bitmap_bit_p (processed, v))
continue;
- partition_t partition = build_rdg_partition_for_vertex (rdg, v);
+ 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 useful partition:\n");
- dump_bitmap (dump_file, partition->stmts);
+ 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. */
-
- BITMAP_FREE (processed);
}
/* Dump to FILE the PARTITIONS. */
static void
-dump_rdg_partitions (FILE *file, vec<partition_t> partitions)
+dump_rdg_partitions (FILE *file, vec<partition *> partitions)
{
int i;
- partition_t partition;
+ partition *partition;
FOR_EACH_VEC_ELT (partitions, i, partition)
debug_bitmap_file (file, partition->stmts);
}
/* Debug PARTITIONS. */
-extern void debug_rdg_partitions (vec<partition_t> );
+extern void debug_rdg_partitions (vec<partition *> );
DEBUG_FUNCTION void
-debug_rdg_partitions (vec<partition_t> partitions)
+debug_rdg_partitions (vec<partition *> partitions)
{
dump_rdg_partitions (stderr, partitions);
}
the RDG. */
static int
-number_of_rw_in_partition (struct graph *rdg, partition_t partition)
+number_of_rw_in_partition (struct graph *rdg, partition *partition)
{
int res = 0;
unsigned i;
static bool
partition_contains_all_rw (struct graph *rdg,
- vec<partition_t> partitions)
+ vec<partition *> partitions)
{
int i;
- partition_t partition;
+ partition *partition;
int nrw = number_of_rw_in_rdg (rdg);
FOR_EACH_VEC_ELT (partitions, i, partition)
return false;
}
-/* Compute partition dependence created by the data references in DRS1
- and DRS2 and modify and return DIR according to that. */
-
-static int
-pg_add_dependence_edges (struct graph *rdg, vec<loop_p> loops, int dir,
- vec<data_reference_p> drs1,
- vec<data_reference_p> drs2)
+int
+loop_distribution::pg_add_dependence_edges (struct graph *rdg, int dir,
+ bitmap drs1, bitmap drs2, vec<ddr_p> *alias_ddrs)
{
- data_reference_p dr1, dr2;
+ 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). */
- for (int ii = 0; drs1.iterate (ii, &dr1); ++ii)
- for (int jj = 0; drs2.iterate (jj, &dr2); ++jj)
- {
- int this_dir = 1;
- ddr_p ddr;
- /* Re-shuffle data-refs to be in dominator order. */
- if (rdg_vertex_for_stmt (rdg, DR_STMT (dr1))
- > rdg_vertex_for_stmt (rdg, DR_STMT (dr2)))
- {
- data_reference_p tem = dr1;
- dr1 = dr2;
- dr2 = tem;
- this_dir = -this_dir;
- }
- ddr = initialize_data_dependence_relation (dr1, dr2, loops);
- compute_affine_dependence (ddr, loops[0]);
- if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
- this_dir = 2;
- else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
- {
- if (DDR_REVERSED_P (ddr))
- {
- data_reference_p tem = dr1;
- dr1 = dr2;
- dr2 = tem;
+ 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 cannot 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
- {
- /* Else as the distance vector is lexicographic positive
- swap the dependence direction. */
+
+ /* Known dependences can still be unordered througout the
+ iteration space, see gcc.dg/tree-ssa/ldist-16.c and
+ gcc.dg/tree-ssa/pr94969.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),
+ DDR_NB_LOOPS (ddr)))
+ ;
+ /* Else as the distance vector is lexicographic positive swap
+ the dependence direction. */
+ else
this_dir = -this_dir;
- }
- }
- else
- this_dir = 0;
- free_dependence_relation (ddr);
- if (dir == 0)
- dir = this_dir;
- else if (dir != this_dir)
- return 2;
- }
+ }
+ 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;
}
return v2->post - v1->post;
}
-/* 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. */
+/* 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. */
+
+struct graph *
+loop_distribution::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 cannot 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);
+ }
+}
+
+void
+loop_distribution::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. */
+void
+loop_distribution::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;
+
+ bool same_type = true, all_builtins = partition_builtin_p (first);
+ for (++j; partitions->iterate (j, &partition); ++j)
+ {
+ if (pg->vertices[j].component != i)
+ continue;
+
+ if (first->type != partition->type)
+ {
+ same_type = false;
+ break;
+ }
+ all_builtins &= partition_builtin_p (partition);
+ }
+ /* Merge SCC if all partitions in SCC have the same type, though the
+ result partition is sequential, because vectorizer can do better
+ runtime alias check. One expecption is all partitions in SCC are
+ builtins. */
+ if (!same_type || all_builtins)
+ bitmap_clear_bit (sccs_to_merge, i);
+ }
+
+ /* 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 to the minimal postordeer number of vertices in scc so
+ that merged partition is sorted correctly against others. */
+ if (pg->vertices[j].post > pg->vertices[k].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 (class 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 (class 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;
+
+ 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),
+ /* ??? Would WELL_ORDERED be safe? */
+ dr_with_seg_len_pair_t::REORDERED);
+
+ 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 (vec<struct partition *> *partitions,
+ class loop *loop, vec<ddr_p> *alias_ddrs)
+{
+ profile_probability prob;
+ basic_block cond_bb;
+ class 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. */
+ bool cancelable_p = flag_tree_loop_vectorize;
+ if (cancelable_p)
+ {
+ unsigned i = 0;
+ struct partition *partition;
+ for (; partitions->iterate (i, &partition); ++i)
+ if (!partition_builtin_p (partition))
+ break;
+
+ /* If all partitions are builtins, distributing it would be profitable and
+ we don't want to cancel the runtime alias checks. */
+ if (i == partitions->length ())
+ cancelable_p = false;
+ }
+
+ /* Generate internal function call for loop distribution alias check if the
+ runtime alias check should be cancelable. */
+ if (cancelable_p)
+ {
+ 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 int
-distribute_loop (struct loop *loop, vec<gimple> stmts,
- control_dependences *cd, int *nb_calls)
+offset_cmp (const void *vp1, const void *vp2)
+{
+ struct partition *p1 = *(struct partition *const *) vp1;
+ struct partition *p2 = *(struct partition *const *) vp2;
+ unsigned HOST_WIDE_INT o1 = p1->builtin->dst_base_offset;
+ unsigned HOST_WIDE_INT o2 = p2->builtin->dst_base_offset;
+ return (o2 < o1) - (o1 < o2);
+}
+
+/* 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. */
+ gcc_stablesort (&(*partitions)[i], j - i, sizeof (*partitions)[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);
+ }
+}
+
+void
+loop_distribution::finalize_partitions (class 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. */
+
+int
+loop_distribution::distribute_loop (class loop *loop, vec<gimple *> stmts,
+ control_dependences *cd, int *nb_calls, bool *destroy_p,
+ bool only_patterns_p)
{
+ ddrs_table = new hash_table<ddr_hasher> (389);
struct graph *rdg;
- partition_t partition;
- bool any_builtin;
+ partition *partition;
int i, nbp;
- graph *pg = NULL;
- int num_sccs = 1;
+ *destroy_p = false;
*nb_calls = 0;
- auto_vec<loop_p, 3> loop_nest;
+ loop_nest.create (0);
if (!find_loop_nest (loop, &loop_nest))
- return 0;
+ {
+ loop_nest.release ();
+ delete ddrs_table;
+ return 0;
+ }
- rdg = build_rdg (loop_nest, cd);
+ datarefs_vec.create (20);
+ has_nonaddressable_dataref_p = false;
+ rdg = build_rdg (loop, cd);
if (!rdg)
{
if (dump_file && (dump_flags & TDF_DETAILS))
"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<partition_t, 3> partitions;
+ auto_vec<struct partition *, 3> partitions;
rdg_build_partitions (rdg, stmts, &partitions);
- any_builtin = false;
+ 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);
+
+ bool any_builtin = false;
+ bool reduction_in_all = false;
FOR_EACH_VEC_ELT (partitions, i, partition)
{
- classify_partition (loop, rdg, partition);
+ reduction_in_all
+ |= 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
+ if (only_patterns_p
&& !any_builtin)
{
nbp = 0;
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. */
- partition_t into;
- if (!flag_tree_loop_distribution)
+ struct partition *into;
+ if (only_patterns_p)
{
for (i = 0; partitions.iterate (i, &into); ++i)
if (!partition_builtin_p (into))
for (++i; partitions.iterate (i, &partition); ++i)
if (!partition_builtin_p (partition))
{
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "fusing non-builtin partitions\n");
- dump_bitmap (dump_file, into->stmts);
- dump_bitmap (dump_file, partition->stmts);
- }
- partition_merge_into (into, partition);
+ partition_merge_into (NULL, into, partition, FUSE_NON_BUILTIN);
partitions.unordered_remove (i);
partition_free (partition);
i--;
for (i = i + 1; partitions.iterate (i, &partition); ++i)
if (partition_reduction_p (partition))
{
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "fusing partitions\n");
- dump_bitmap (dump_file, into->stmts);
- dump_bitmap (dump_file, partition->stmts);
- fprintf (dump_file, "because they have reductions\n");
- }
- partition_merge_into (into, partition);
+ partition_merge_into (rdg, into, partition, FUSE_REDUCTION);
partitions.unordered_remove (i);
partition_free (partition);
i--;
memory accesses. */
for (i = 0; partitions.iterate (i, &into); ++i)
{
- if (partition_builtin_p (into))
+ 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 (!partition_builtin_p (partition)
- && similar_memory_accesses (rdg, into, partition))
+ if (share_memory_accesses (rdg, into, partition))
{
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "fusing partitions\n");
- dump_bitmap (dump_file, into->stmts);
- dump_bitmap (dump_file, partition->stmts);
- fprintf (dump_file, "because they have similar "
- "memory accesses\n");
- }
- partition_merge_into (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. */
- if (partitions.length () > 1)
- {
- pg = new_graph (partitions.length ());
- struct pgdata {
- partition_t partition;
- vec<data_reference_p> writes;
- vec<data_reference_p> reads;
- };
-#define PGDATA(i) ((pgdata *)(pg->vertices[i].data))
- for (i = 0; partitions.iterate (i, &partition); ++i)
+ /* Put a non-builtin partition last if we need to preserve a reduction.
+ ??? This is a workaround that makes sort_partitions_by_post_order do
+ the correct thing while in reality it should sort each component
+ separately and then put the component with a reduction or a non-builtin
+ last. */
+ if (reduction_in_all
+ && partition_builtin_p (partitions.last()))
+ FOR_EACH_VEC_ELT (partitions, i, partition)
+ if (!partition_builtin_p (partition))
{
- vertex *v = &pg->vertices[i];
- pgdata *data = new pgdata;
- data_reference_p dr;
- /* FIXME - leaks. */
- v->data = data;
- bitmap_iterator bi;
- unsigned j;
- data->partition = partition;
- data->reads = vNULL;
- data->writes = vNULL;
- EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, j, bi)
- for (int k = 0; RDG_DATAREFS (rdg, j).iterate (k, &dr); ++k)
- if (DR_IS_READ (dr))
- data->reads.safe_push (dr);
- else
- data->writes.safe_push (dr);
- }
- partition_t partition1, partition2;
- for (i = 0; partitions.iterate (i, &partition1); ++i)
- for (int 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;
- dir = pg_add_dependence_edges (rdg, loop_nest, dir,
- PGDATA(i)->writes,
- PGDATA(j)->reads);
- if (dir != 2)
- dir = pg_add_dependence_edges (rdg, loop_nest, dir,
- PGDATA(i)->reads,
- PGDATA(j)->writes);
- if (dir != 2)
- dir = pg_add_dependence_edges (rdg, loop_nest, dir,
- PGDATA(i)->writes,
- PGDATA(j)->writes);
- if (dir == 1 || dir == 2)
- add_edge (pg, i, j);
- if (dir == -1 || dir == 2)
- add_edge (pg, j, i);
- }
-
- /* Add edges to the reduction partition (if any) to force it last. */
- unsigned j;
- for (j = 0; partitions.iterate (j, &partition); ++j)
- if (partition_reduction_p (partition))
+ partitions.unordered_remove (i);
+ partitions.quick_push (partition);
break;
- if (j < partitions.length ())
- {
- for (unsigned i = 0; partitions.iterate (i, &partition); ++i)
- if (i != j)
- add_edge (pg, i, j);
}
- /* Compute partitions we cannot separate and fuse them. */
- num_sccs = graphds_scc (pg, NULL);
- for (i = 0; i < num_sccs; ++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.
+ Also if loop has any data reference which may be not addressable
+ since alias check needs to take, compare address of the object. */
+ if (loop->inner || has_nonaddressable_dataref_p)
+ merge_dep_scc_partitions (rdg, &partitions, false);
+ else
{
- partition_t first;
- int j;
- for (j = 0; partitions.iterate (j, &first); ++j)
- if (pg->vertices[j].component == i)
- break;
- for (j = j + 1; partitions.iterate (j, &partition); ++j)
- if (pg->vertices[j].component == i)
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "fusing partitions\n");
- dump_bitmap (dump_file, first->stmts);
- dump_bitmap (dump_file, partition->stmts);
- fprintf (dump_file, "because they are in the same "
- "dependence SCC\n");
- }
- partition_merge_into (first, partition);
- partitions[j] = NULL;
- partition_free (partition);
- PGDATA (j)->partition = NULL;
- }
+ merge_dep_scc_partitions (rdg, &partitions, true);
+ if (partitions.length () > 1)
+ break_alias_scc_partitions (rdg, &partitions, &alias_ddrs);
}
+ }
- /* Now order the remaining nodes in postorder. */
- qsort (pg->vertices, pg->n_vertices, sizeof (vertex), pgcmp);
- partitions.truncate (0);
- for (i = 0; i < pg->n_vertices; ++i)
+ finalize_partitions (loop, &partitions, &alias_ddrs);
+
+ /* If there is a reduction in all partitions make sure the last one
+ is not classified for builtin code generation. */
+ if (reduction_in_all)
+ {
+ partition = partitions.last ();
+ if (only_patterns_p
+ && partition_builtin_p (partition)
+ && !partition_builtin_p (partitions[0]))
{
- pgdata *data = PGDATA (i);
- if (data->partition)
- partitions.safe_push (data->partition);
- data->reads.release ();
- data->writes.release ();
- delete data;
+ nbp = 0;
+ goto ldist_done;
}
- gcc_assert (partitions.length () == (unsigned)num_sccs);
- free_graph (pg);
+ partition->kind = PKIND_NORMAL;
}
nbp = partitions.length ();
goto ldist_done;
}
+ if (version_for_distribution_p (&partitions, &alias_ddrs))
+ version_loop_by_alias_check (&partitions, loop, &alias_ddrs);
+
if (dump_file && (dump_flags & TDF_DETAILS))
- dump_rdg_partitions (dump_file, partitions);
+ {
+ 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)++;
- generate_code_for_partition (loop, partition, i < nbp - 1);
+ *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);
return nbp - *nb_calls;
}
-/* Distribute all loops in the current function. */
-static unsigned int
-tree_loop_distribution (void)
+void loop_distribution::bb_top_order_init (void)
+{
+ 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);
+}
+
+void loop_distribution::bb_top_order_destroy ()
+{
+ free (bb_top_order_index);
+ bb_top_order_index = NULL;
+ bb_top_order_index_size = 0;
+}
+
+
+/* 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 (class loop *loop, vec<gimple *> *work_list)
{
- struct loop *loop;
+ 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);
+
+ /* Ignore clobbers, they do not have true side effects. */
+ if (gimple_clobber_p (stmt))
+ continue;
+
+ /* 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 class loop *
+prepare_perfect_loop_nest (class loop *loop)
+{
+ class 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)
+ && !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
+loop_distribution::execute (function *fun)
+{
+ class 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;
+
+ bb_top_order_init ();
- FOR_ALL_BB_FN (bb, cfun)
+ FOR_ALL_BB_FN (bb, fun)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
walking to innermost loops. */
FOR_EACH_LOOP (loop, LI_ONLY_INNERMOST)
{
- auto_vec<gimple> work_list;
- basic_block *bbs;
- int num = loop->num;
- unsigned int i;
-
- /* If the loop doesn't have a single exit we will fail anyway,
- so do that early. */
- if (!single_exit (loop))
+ /* Don't distribute multiple exit edges loop, or cold loop when
+ not doing pattern detection. */
+ if (!single_exit (loop)
+ || (!flag_tree_loop_distribute_patterns
+ && !optimize_loop_for_speed_p (loop)))
continue;
- /* Only optimize hot loops. */
- if (!optimize_loop_for_speed_p (loop))
+ /* Don't distribute loop if niters is unknown. */
+ tree niters = number_of_latch_executions (loop);
+ if (niters == NULL_TREE || niters == chrec_dont_know)
continue;
- /* Initialize the worklist with stmts we seed the partitions with. */
- bbs = get_loop_body_in_dom_order (loop);
- for (i = 0; i < loop->num_nodes; ++i)
+ /* Get the perfect loop nest for distribution. */
+ loop = prepare_perfect_loop_nest (loop);
+ for (; loop; loop = loop->inner)
{
- gimple_stmt_iterator gsi;
- for (gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple phi = gsi_stmt (gsi);
- 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 (gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple stmt = gsi_stmt (gsi);
+ auto_vec<gimple *> work_list;
+ if (!find_seed_stmts_for_distribution (loop, &work_list))
+ break;
- /* If there is a stmt with side-effects bail out - we
- cannot and should not distribute this loop. */
- if (gimple_has_side_effects (stmt))
- {
- work_list.truncate (0);
- goto out;
- }
-
- /* 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);
- }
- }
-out:
- free (bbs);
-
- int nb_generated_loops = 0;
- int nb_generated_calls = 0;
- location_t loc = find_loop_location (loop);
- if (work_list.length () > 0)
- {
+ const char *str = loop->inner ? " nest" : "";
+ dump_user_location_t loc = find_loop_location (loop);
if (!cd)
{
calculate_dominance_info (CDI_DOMINATORS);
calculate_dominance_info (CDI_POST_DOMINATORS);
- cd = new control_dependences (create_edge_list ());
+ cd = new control_dependences ();
free_dominance_info (CDI_POST_DOMINATORS);
}
- nb_generated_loops = distribute_loop (loop, work_list, cd,
- &nb_generated_calls);
- }
- if (nb_generated_loops + nb_generated_calls > 0)
- {
- changed = true;
- dump_printf_loc (MSG_OPTIMIZED_LOCATIONS,
- loc, "Loop %d distributed: split to %d loops "
- "and %d library calls.\n",
- num, nb_generated_loops, nb_generated_calls);
+ bool destroy_p;
+ int nb_generated_loops, nb_generated_calls;
+ nb_generated_loops
+ = distribute_loop (loop, work_list, cd, &nb_generated_calls,
+ &destroy_p, (!optimize_loop_for_speed_p (loop)
+ || !flag_tree_loop_distribution));
+ if (destroy_p)
+ loops_to_be_destroyed.safe_push (loop);
+
+ if (nb_generated_loops + nb_generated_calls > 0)
+ {
+ changed = true;
+ if (dump_enabled_p ())
+ 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);
}
- else if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Loop %d is the same.\n", num);
}
if (cd)
delete cd;
+ if (bb_top_order_index != NULL)
+ bb_top_order_destroy ();
+
if (changed)
{
- mark_virtual_operands_for_renaming (cfun);
+ /* Destroy loop bodies that could not be reused. Do this late as we
+ otherwise can end up refering to stale data in control dependences. */
+ unsigned i;
+ FOR_EACH_VEC_ELT (loops_to_be_destroyed, i, loop)
+ destroy_loop (loop);
+
+ /* Cached scalar evolutions now may refer to wrong or non-existing
+ loops. */
+ scev_reset_htab ();
+ mark_virtual_operands_for_renaming (fun);
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
}
-#ifdef ENABLE_CHECKING
- verify_loop_structure ();
-#endif
+ checking_verify_loop_structure ();
- return 0;
+ return changed ? TODO_cleanup_cfg : 0;
}
-static bool
-gate_tree_loop_distribution (void)
-{
- return flag_tree_loop_distribution
- || flag_tree_loop_distribute_patterns;
-}
+
+/* Distribute all loops in the current function. */
namespace {
GIMPLE_PASS, /* type */
"ldist", /* name */
OPTGROUP_LOOP, /* optinfo_flags */
- true, /* has_gate */
- true, /* has_execute */
TV_TREE_LOOP_DISTRIBUTION, /* tv_id */
( PROP_cfg | PROP_ssa ), /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_verify_ssa, /* todo_flags_finish */
+ 0, /* todo_flags_finish */
};
class pass_loop_distribution : public gimple_opt_pass
{}
/* opt_pass methods: */
- bool gate () { return gate_tree_loop_distribution (); }
- unsigned int execute () { return tree_loop_distribution (); }
+ virtual bool gate (function *)
+ {
+ return flag_tree_loop_distribution
+ || flag_tree_loop_distribute_patterns;
+ }
+
+ virtual unsigned int execute (function *);
}; // class pass_loop_distribution
+unsigned int
+pass_loop_distribution::execute (function *fun)
+{
+ return loop_distribution ().execute (fun);
+}
+
} // anon namespace
gimple_opt_pass *
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