Hi,
As described in message of previous patch:
This patch set fixes both PRs in the opposite way: Instead of find dominance
insertion position for root reference, we resort zero-distance references of
combined chain by their position information so that new root reference must
dominate others. This should be more efficient because we avoid function call
to stmt_dominates_stmt_p.
Bootstrap and test on x86_64 and AArch64 in patch set. Is it OK?
Thanks,
bin
2017-11-02 Bin Cheng <bin.ch...@arm.com>
PR tree-optimization/82726
PR tree-optimization/70754
* tree-predcom.c (<map>, INCLUDE_ALGORITHM): New headers.
(order_drefs_by_pos): New function.
(combine_chains): Move code setting has_max_use_after to...
(try_combine_chains): ...here. New parameter. Sort combined chains
according to position information.
(tree_predictive_commoning_loop): Update call to above function.
(update_pos_for_combined_chains, pcom_stmt_dominates_stmt_p): New.
gcc/testsuite
2017-11-02 Bin Cheng <bin.ch...@arm.com>
PR tree-optimization/82726
* gcc.dg/tree-ssa/pr82726.c: New test.From 843cef544a46236e40063416cebc8037736ad18a Mon Sep 17 00:00:00 2001
From: Bin Cheng <binch...@e108451-lin.cambridge.arm.com>
Date: Wed, 1 Nov 2017 17:43:55 +0000
Subject: [PATCH 2/2] pr82726-20171102.txt
---
gcc/testsuite/gcc.dg/tree-ssa/pr82726.c | 26 ++++++
gcc/tree-predcom.c | 159 ++++++++++++++++++++++++++++----
2 files changed, 169 insertions(+), 16 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr82726.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c b/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c
new file mode 100644
index 0000000..179f93a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr82726.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 --param tree-reassoc-width=4" } */
+/* { dg-additional-options "-mavx2" { target avx2_runtime } } */
+
+#define N 40
+#define M 128
+unsigned int in[N+M];
+unsigned short out[N];
+
+/* Outer-loop vectorization. */
+
+void
+foo (){
+ int i,j;
+ unsigned int diff;
+
+ for (i = 0; i < N; i++) {
+ diff = 0;
+ for (j = 0; j < M; j+=8) {
+ diff += in[j+i];
+ }
+ out[i]=(unsigned short)diff;
+ }
+
+ return;
+}
diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c
index 24d7c9c..a243bce 100644
--- a/gcc/tree-predcom.c
+++ b/gcc/tree-predcom.c
@@ -201,6 +201,8 @@ along with GCC; see the file COPYING3. If not see
i * i with ii_last + 2 * i + 1), to generalize strength reduction. */
#include "config.h"
+#include <map>
+#define INCLUDE_ALGORITHM /* std::sort */
#include "system.h"
#include "coretypes.h"
#include "backend.h"
@@ -1020,6 +1022,14 @@ order_drefs (const void *a, const void *b)
return (*da)->pos - (*db)->pos;
}
+/* Compares two drefs A and B by their position. Callback for std::sort. */
+
+static bool
+order_drefs_by_pos (dref a, dref b)
+{
+ return a->pos < b->pos;
+}
+
/* Returns root of the CHAIN. */
static inline dref
@@ -2633,7 +2643,6 @@ combine_chains (chain_p ch1, chain_p ch2)
bool swap = false;
chain_p new_chain;
unsigned i;
- gimple *root_stmt;
tree rslt_type = NULL_TREE;
if (ch1 == ch2)
@@ -2675,31 +2684,56 @@ combine_chains (chain_p ch1, chain_p ch2)
new_chain->refs.safe_push (nw);
}
- new_chain->has_max_use_after = false;
- root_stmt = get_chain_root (new_chain)->stmt;
- for (i = 1; new_chain->refs.iterate (i, &nw); i++)
- {
- if (nw->distance == new_chain->length
- && !stmt_dominates_stmt_p (nw->stmt, root_stmt))
- {
- new_chain->has_max_use_after = true;
- break;
- }
- }
-
ch1->combined = true;
ch2->combined = true;
return new_chain;
}
-/* Try to combine the CHAINS. */
+/* Recursively update position information of all offspring chains to ROOT
+ chain's position information. */
+
+static void
+update_pos_for_combined_chains (chain_p root)
+{
+ chain_p ch1 = root->ch1, ch2 = root->ch2;
+ dref ref, ref1, ref2;
+ for (unsigned j = 0; (root->refs.iterate (j, &ref)
+ && ch1->refs.iterate (j, &ref1)
+ && ch2->refs.iterate (j, &ref2)); ++j)
+ ref1->pos = ref2->pos = ref->pos;
+
+ if (ch1->type == CT_COMBINATION)
+ update_pos_for_combined_chains (ch1);
+ if (ch2->type == CT_COMBINATION)
+ update_pos_for_combined_chains (ch2);
+}
+
+/* Returns true if statement S1 dominates statement S2. */
+
+static bool
+pcom_stmt_dominates_stmt_p (std::map<gimple *, int> &stmts_map,
+ gimple *s1, gimple *s2)
+{
+ basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2);
+
+ if (!bb1 || s1 == s2)
+ return true;
+
+ if (bb1 == bb2)
+ return stmts_map[s1] < stmts_map[s2];
+
+ return dominated_by_p (CDI_DOMINATORS, bb2, bb1);
+}
+
+/* Try to combine the CHAINS in LOOP. */
static void
-try_combine_chains (vec<chain_p> *chains)
+try_combine_chains (struct loop *loop, vec<chain_p> *chains)
{
unsigned i, j;
chain_p ch1, ch2, cch;
auto_vec<chain_p> worklist;
+ bool combined_p = false;
FOR_EACH_VEC_ELT (*chains, i, ch1)
if (chain_can_be_combined_p (ch1))
@@ -2721,6 +2755,99 @@ try_combine_chains (vec<chain_p> *chains)
{
worklist.safe_push (cch);
chains->safe_push (cch);
+ combined_p = true;
+ break;
+ }
+ }
+ }
+ if (!combined_p)
+ return;
+
+ /* Setup UID for all statements in dominance order. */
+ std::map<gimple *, int> stmts_map;
+ basic_block *bbs = get_loop_body_in_dom_order (loop);
+ for (i = 0; i < loop->num_nodes; i++)
+ {
+ int uid = 0;
+ basic_block bb = bbs[i];
+
+ for (gimple_stmt_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi);
+ gsi_next (&bsi))
+ {
+ gimple *stmt = gsi_stmt (bsi);
+ if (!virtual_operand_p (gimple_phi_result (as_a<gphi *> (stmt))))
+ stmts_map[stmt] = uid;
+ }
+
+ for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi);
+ gsi_next (&bsi))
+ {
+ gimple *stmt = gsi_stmt (bsi);
+ if (gimple_code (stmt) != GIMPLE_LABEL && !is_gimple_debug (stmt))
+ stmts_map[stmt] = ++uid;
+ }
+ }
+ free (bbs);
+
+ /* Re-association in combined chains may generate statements different to
+ order of references of the original chain. We need to keep references
+ of combined chain in dominance order so that all uses will be inserted
+ after definitions. Note:
+ A) This is necessary for all combined chains.
+ B) This is only necessary for ZERO distance references because other
+ references inherit value from loop carried PHIs.
+
+ We first update position information for all combined chains. */
+ dref ref;
+ for (i = 0; chains->iterate (i, &ch1); ++i)
+ {
+ if (ch1->type != CT_COMBINATION || ch1->combined)
+ continue;
+
+ for (j = 0; ch1->refs.iterate (j, &ref); ++j)
+ ref->pos = stmts_map[ref->stmt];
+
+ update_pos_for_combined_chains (ch1);
+ }
+ /* Then sort references according to newly updated position information. */
+ for (i = 0; chains->iterate (i, &ch1); ++i)
+ {
+ if (ch1->type != CT_COMBINATION && !ch1->combined)
+ continue;
+
+ /* Find the first reference with non-ZERO distance. */
+ if (ch1->length == 0)
+ j = ch1->refs.length();
+ else
+ {
+ for (j = 0; ch1->refs.iterate (j, &ref); ++j)
+ if (ref->distance != 0)
+ break;
+ }
+
+ /* Sort all ZERO distance references by position. */
+ std::sort (&ch1->refs[0], &ch1->refs[0] + j, order_drefs_by_pos);
+
+ if (ch1->combined)
+ continue;
+
+ /* For ZERO length chain, has_max_use_after must be true since root
+ combined stmt must dominates others. */
+ if (ch1->length == 0)
+ {
+ ch1->has_max_use_after = true;
+ continue;
+ }
+ /* Check if there is use at max distance after root for combined chains
+ and set flag accordingly. */
+ ch1->has_max_use_after = false;
+ gimple *root_stmt = get_chain_root (ch1)->stmt;
+ for (j = 1; ch1->refs.iterate (j, &ref); ++j)
+ {
+ if (ref->distance == ch1->length
+ && !pcom_stmt_dominates_stmt_p (stmts_map, ref->stmt, root_stmt))
+ {
+ ch1->has_max_use_after = true;
break;
}
}
@@ -3058,7 +3185,7 @@ tree_predictive_commoning_loop (struct loop *loop)
loop_closed_ssa = prepare_finalizers (loop, chains);
/* Try to combine the chains that are always worked with together. */
- try_combine_chains (&chains);
+ try_combine_chains (loop, &chains);
insert_init_seqs (loop, chains);
--
1.9.1
