Hi,
This patch computes and caches data dependence relation in a hash table
so that it can be queried multiple times later for partition dependence
check.
Bootstrap and test on x86_64 and AArch64. Is it OK?
Thanks,
bin
2017-06-07 Bin Cheng <bin.ch...@arm.com>
* tree-loop-distribution.c (struct ddr_entry, ddr_entry_hasher): New.
(ddr_entry_hasher::hash, ::equal, get_data_dependence): New function.
(ddrs_vec, ddrs_table): New.
(classify_partition): Call get_data_dependence.
(pg_add_dependence_edges): Ditto.
(distribute_loop): Initialize data dependence global variables.From 6075d1db94b7f130a91bba53125bed5754a46f59 Mon Sep 17 00:00:00 2001
From: Bin Cheng <binch...@e108451-lin.cambridge.arm.com>
Date: Fri, 9 Jun 2017 13:02:09 +0100
Subject: [PATCH 10/14] cache-data-dependence-20170607.txt
---
gcc/tree-loop-distribution.c | 118 +++++++++++++++++++++++++++++++++----------
1 file changed, 92 insertions(+), 26 deletions(-)
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 90dc8ea..eacd9a1 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -66,6 +66,43 @@ along with GCC; see the file COPYING3. If not see
#include "tree-vectorizer.h"
+/* Hashtable entry for data reference relation. */
+struct ddr_entry
+{
+ data_reference_p a;
+ data_reference_p b;
+ ddr_p ddr;
+ hashval_t hash;
+};
+
+/* Hashtable helpers. */
+
+struct ddr_entry_hasher : delete_ptr_hash <ddr_entry>
+{
+ static inline hashval_t hash (const ddr_entry *);
+ static inline bool equal (const ddr_entry *, const ddr_entry *);
+};
+
+/* Hash function for data reference relation. */
+
+inline hashval_t
+ddr_entry_hasher::hash (const ddr_entry *entry)
+{
+ return entry->hash;
+}
+
+/* Hash table equality function for data reference relation. */
+
+inline bool
+ddr_entry_hasher::equal (const ddr_entry *entry1, const ddr_entry *entry2)
+{
+ return (entry1->hash == entry2->hash
+ && DR_STMT (entry1->a) == DR_STMT (entry2->a)
+ && DR_STMT (entry1->b) == DR_STMT (entry2->b)
+ && operand_equal_p (DR_REF (entry1->a), DR_REF (entry2->a), 0)
+ && operand_equal_p (DR_REF (entry1->b), DR_REF (entry2->b), 0));
+}
+
/* The loop (nest) to be distributed. */
static vec<loop_p> *loop_nest;
@@ -75,6 +112,13 @@ static vec<data_reference_p> *datarefs_vec;
/* Map of data reference in the loop to a unique id. */
static hash_map<data_reference_p, int> *datarefs_map;
+/* Vector of data dependence relations. */
+static vec<ddr_p> *ddrs_vec;
+
+/* Hash table for data dependence relation in the loop to be distributed. */
+static hash_table<ddr_entry_hasher> *ddrs_table;
+
+
/* A Reduced Dependence Graph (RDG) vertex representing a statement. */
struct rdg_vertex
{
@@ -1061,6 +1105,41 @@ generate_code_for_partition (struct loop *loop,
return false;
}
+/* Return data dependence relation for data references A and B. The two
+ data references must be in lexicographic order wrto reduced dependence
+ graph RDG. We firstly try to find ddr from global ddr hash table. If
+ it doesn't exist, compute the ddr and cache it. */
+
+static data_dependence_relation *
+get_data_dependence (struct graph *rdg, data_reference_p a, data_reference_p b)
+{
+ struct ddr_entry 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;
+ ent.hash = iterative_hash_expr (DR_REF (a), 0);
+ ent.hash = iterative_hash_expr (DR_REF (b), ent.hash);
+ 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]);
+
+ ddrs_vec->safe_push (ddr);
+
+ *slot = new ddr_entry ();
+ (*slot)->a = a;
+ (*slot)->b = b;
+ (*slot)->ddr = ddr;
+ (*slot)->hash = ent.hash;
+ }
+
+ return (*slot)->ddr;
+}
/* Returns a partition with all the statements needed for computing
the vertex V of the RDG, also including the loop exit conditions. */
@@ -1231,44 +1310,27 @@ classify_partition (loop_p loop, struct graph *rdg,
partition *partition)
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);
+ ddr_p ddr = get_data_dependence (rdg, single_load, single_store);
if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
- {
- free_dependence_relation (ddr);
- loops.release ();
- return;
- }
+ return;
+
if (DDR_ARE_DEPENDENT (ddr) != chrec_known)
{
if (DDR_NUM_DIST_VECTS (ddr) == 0)
- {
- free_dependence_relation (ddr);
- loops.release ();
- return;
- }
+ 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;
- }
+ return;
}
partition->kind = PKIND_MEMMOVE;
}
else
partition->kind = PKIND_MEMCPY;
- free_dependence_relation (ddr);
- loops.release ();
partition->main_dr = single_store;
partition->secondary_dr = single_load;
partition->niter = nb_iter;
@@ -1532,8 +1594,7 @@ pg_add_dependence_edges (struct graph *rdg, int dir,
std::swap (dr1, dr2);
this_dir = -this_dir;
}
- ddr = initialize_data_dependence_relation (dr1, dr2, *loop_nest);
- compute_affine_dependence (ddr, (*loop_nest)[0]);
+ ddr = get_data_dependence (rdg, dr1, dr2);
if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
this_dir = 2;
else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
@@ -1559,7 +1620,6 @@ pg_add_dependence_edges (struct graph *rdg, int dir,
}
else
this_dir = 0;
- free_dependence_relation (ddr);
if (this_dir == 2)
return 2;
else if (dir == 0)
@@ -1652,6 +1712,9 @@ distribute_loop (struct loop *loop, vec<gimple *> stmts,
if (dump_file && (dump_flags & TDF_DETAILS))
dump_rdg (dump_file, rdg);
+ ddrs_vec = new vec<ddr_p> ();
+ ddrs_table = new hash_table<ddr_entry_hasher> (389);
+
auto_vec<struct partition *, 3> partitions;
rdg_build_partitions (rdg, stmts, &partitions);
@@ -1840,6 +1903,9 @@ distribute_loop (struct loop *loop, vec<gimple *> stmts,
ldist_done:
loop_nest->release ();
delete loop_nest;
+ free_dependence_relations (*ddrs_vec);
+ delete ddrs_vec;
+ delete ddrs_table;
free_data_refs (*datarefs_vec);
delete datarefs_vec;
delete datarefs_map;
--
1.9.1
