From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Richard Biener <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org, Andreas Krebbel <krebbel@gcc.gnu.org>,
Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH v3 1/3] reassoc: Do not bias loop-carried PHIs early
Date: Sun, 26 Sep 2021 13:09:34 +0200 [thread overview]
Message-ID: <20210926110936.344019-2-iii@linux.ibm.com> (raw)
In-Reply-To: <20210926110936.344019-1-iii@linux.ibm.com>
Biasing loop-carried PHIs during the 1st reassociation pass interferes
with reduction chains and does not bring measurable benefits, so do it
only during the 2nd reassociation pass.
gcc/ChangeLog:
* passes.def (pass_reassoc): Rename parameter to early_p.
* tree-ssa-reassoc.c (reassoc_bias_loop_carried_phi_ranks_p):
New variable.
(phi_rank): Don't bias loop-carried phi ranks
before vectorization pass.
(execute_reassoc): Add bias_loop_carried_phi_ranks_p parameter.
(pass_reassoc::pass_reassoc): Add bias_loop_carried_phi_ranks_p
initializer.
(pass_reassoc::set_param): Set bias_loop_carried_phi_ranks_p
value.
(pass_reassoc::execute): Pass bias_loop_carried_phi_ranks_p to
execute_reassoc.
(pass_reassoc::bias_loop_carried_phi_ranks_p): New member.
---
gcc/passes.def | 4 ++--
gcc/tree-ssa-reassoc.c | 16 ++++++++++++++--
2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/gcc/passes.def b/gcc/passes.def
index d7a1f8c97a6..c5f915d04c6 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -242,7 +242,7 @@ along with GCC; see the file COPYING3. If not see
/* Identify paths that should never be executed in a conforming
program and isolate those paths. */
NEXT_PASS (pass_isolate_erroneous_paths);
- NEXT_PASS (pass_reassoc, true /* insert_powi_p */);
+ NEXT_PASS (pass_reassoc, true /* early_p */);
NEXT_PASS (pass_dce);
NEXT_PASS (pass_forwprop);
NEXT_PASS (pass_phiopt, false /* early_p */);
@@ -325,7 +325,7 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_lower_vector_ssa);
NEXT_PASS (pass_lower_switch);
NEXT_PASS (pass_cse_reciprocals);
- NEXT_PASS (pass_reassoc, false /* insert_powi_p */);
+ NEXT_PASS (pass_reassoc, false /* early_p */);
NEXT_PASS (pass_strength_reduction);
NEXT_PASS (pass_split_paths);
NEXT_PASS (pass_tracer);
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 8498cfc7aa8..420c14e8cf5 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -180,6 +180,10 @@ along with GCC; see the file COPYING3. If not see
point 3a in the pass header comment. */
static bool reassoc_insert_powi_p;
+/* Enable biasing ranks of loop accumulators. We don't want this before
+ vectorization, since it interferes with reduction chains. */
+static bool reassoc_bias_loop_carried_phi_ranks_p;
+
/* Statistics */
static struct
{
@@ -269,6 +273,9 @@ phi_rank (gimple *stmt)
use_operand_p use;
gimple *use_stmt;
+ if (!reassoc_bias_loop_carried_phi_ranks_p)
+ return bb_rank[bb->index];
+
/* We only care about real loops (those with a latch). */
if (!father->latch)
return bb_rank[bb->index];
@@ -6940,9 +6947,10 @@ fini_reassoc (void)
optimization of a gimple conditional. Otherwise returns zero. */
static unsigned int
-execute_reassoc (bool insert_powi_p)
+execute_reassoc (bool insert_powi_p, bool bias_loop_carried_phi_ranks_p)
{
reassoc_insert_powi_p = insert_powi_p;
+ reassoc_bias_loop_carried_phi_ranks_p = bias_loop_carried_phi_ranks_p;
init_reassoc ();
@@ -6983,15 +6991,19 @@ public:
{
gcc_assert (n == 0);
insert_powi_p = param;
+ bias_loop_carried_phi_ranks_p = !param;
}
virtual bool gate (function *) { return flag_tree_reassoc != 0; }
virtual unsigned int execute (function *)
- { return execute_reassoc (insert_powi_p); }
+ {
+ return execute_reassoc (insert_powi_p, bias_loop_carried_phi_ranks_p);
+ }
private:
/* Enable insertion of __builtin_powi calls during execute_reassoc. See
point 3a in the pass header comment. */
bool insert_powi_p;
+ bool bias_loop_carried_phi_ranks_p;
}; // class pass_reassoc
} // anon namespace
--
2.31.1
next prev parent reply other threads:[~2021-09-26 11:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-26 11:09 [PATCH v3 0/3] reassoc: Propagate PHI_LOOP_BIAS along single uses Ilya Leoshkevich
2021-09-26 11:09 ` Ilya Leoshkevich [this message]
2021-09-28 11:21 ` [PATCH v3 1/3] reassoc: Do not bias loop-carried PHIs early Richard Biener
2021-09-26 11:09 ` [PATCH v3 2/3] reassoc: Propagate PHI_LOOP_BIAS along single uses Ilya Leoshkevich
2021-09-28 11:24 ` Richard Biener
2021-09-26 11:09 ` [PATCH v3 3/3] reassoc: Test rank biasing Ilya Leoshkevich
2021-09-28 11:28 ` Richard Biener
2021-09-28 11:46 ` Ilya Leoshkevich
2021-09-28 12:38 ` Richard Biener
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