From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1666) id 486FA3847700; Wed, 3 Apr 2024 06:57:08 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 486FA3847700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1712127428; bh=wDffiFUWM9v672cIi/w2bjY5OcqvJaQyLIkwhXdVCck=; h=From:To:Subject:Date:From; b=blNkTGNkSAw+2ldoPZZKofcUghas6HjIHwm6SaJGicSXYmuyRtd3FvyLwI3H7fZq8 uDlFQLdWquOq69xNtUs7O3IB9v+o3P0CqwxqxDcqM4olRjEPIgUxX0AFvU33jJ1Zs4 91TsYfaZEHvaTc7uwCLFnDEu2Vjvf84QW1qmBz3s= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Richard Biener To: gcc-cvs@gcc.gnu.org Subject: [gcc r14-9767] tree-optimization/114557 - reduce ehcleanup peak memory use X-Act-Checkin: gcc X-Git-Author: Richard Biener X-Git-Refname: refs/heads/master X-Git-Oldrev: 8677182f32234786fccce25583232ec5181dde75 X-Git-Newrev: e7b7188b1cf8c174f0e890d4ac279ff480b51043 Message-Id: <20240403065708.486FA3847700@sourceware.org> Date: Wed, 3 Apr 2024 06:57:08 +0000 (GMT) List-Id: https://gcc.gnu.org/g:e7b7188b1cf8c174f0e890d4ac279ff480b51043 commit r14-9767-ge7b7188b1cf8c174f0e890d4ac279ff480b51043 Author: Richard Biener Date: Tue Apr 2 12:31:04 2024 +0200 tree-optimization/114557 - reduce ehcleanup peak memory use The following reduces peak memory use for the PR114480 testcase at -O1 which is almost exclusively spent by the ehcleanup pass in allocating PHI nodes. The free_phinodes cache we maintain isn't very effective since it has effectively two slots, one for 4 and one for 9 argument PHIs and it is only ever used for allocations up to 9 arguments but we put all larger PHIs in the 9 argument bucket. This proves uneffective resulting in much garbage to be kept when incrementally growing PHI nodes by edge redirection. The mitigation is to rely on the GC freelist for larger sizes and thus immediately return all larger bucket sized PHIs to it via ggc_free. This reduces the peak memory use from 19.8GB to 11.3GB and compile-time from 359s to 168s. PR tree-optimization/114557 PR tree-optimization/114480 * tree-phinodes.cc (release_phi_node): Return PHIs from allocation buckets not covered by free_phinodes to GC. (remove_phi_node): Release the PHI LHS before freeing the PHI node. * tree-vect-loop.cc (vectorizable_live_operation): Get PHI lhs before releasing it. Diff: --- gcc/tree-phinodes.cc | 10 +++++++++- gcc/tree-vect-loop.cc | 2 +- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/gcc/tree-phinodes.cc b/gcc/tree-phinodes.cc index ddd731323e1..5a7e4a94e57 100644 --- a/gcc/tree-phinodes.cc +++ b/gcc/tree-phinodes.cc @@ -223,6 +223,14 @@ release_phi_node (gimple *phi) delink_imm_use (imm); } + /* Immediately return the memory to the allocator when we would + only ever re-use it for a smaller size allocation. */ + if (len - 2 >= NUM_BUCKETS - 2) + { + ggc_free (phi); + return; + } + bucket = len > NUM_BUCKETS - 1 ? NUM_BUCKETS - 1 : len; bucket -= 2; vec_safe_push (free_phinodes[bucket], phi); @@ -445,9 +453,9 @@ remove_phi_node (gimple_stmt_iterator *gsi, bool release_lhs_p) /* If we are deleting the PHI node, then we should release the SSA_NAME node so that it can be reused. */ - release_phi_node (phi); if (release_lhs_p) release_ssa_name (gimple_phi_result (phi)); + release_phi_node (phi); } /* Remove all the phi nodes from BB. */ diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index f33629e9b04..984636edbc5 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -10962,8 +10962,8 @@ vectorizable_live_operation (vec_info *vinfo, stmt_vec_info stmt_info, lhs_type, &exit_gsi); auto gsi = gsi_for_stmt (use_stmt); - remove_phi_node (&gsi, false); tree lhs_phi = gimple_phi_result (use_stmt); + remove_phi_node (&gsi, false); gimple *copy = gimple_build_assign (lhs_phi, new_tree); gsi_insert_before (&exit_gsi, copy, GSI_SAME_STMT); break;