From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1666) id 5AE843858D33; Fri, 3 Mar 2023 07:31:50 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5AE843858D33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1677828710; bh=N3KinG2OOqWBO5ycxukVR73eyGmVqaOnaVlWNnTx6A8=; h=From:To:Subject:Date:From; b=uBrVrcvH88/U6go4nNBsCqnLi2jKUw4q+gqhVMGWLajSwNFnNf2hY+g88c+NBINnU nXC9xHFgXokhQuzP1cPycFNKiMC1N2Ffu1a2UGQabbcor7aehMbDRYILMH5vK3Ybw9 ln9+h57DKsVE3hN2J5Qiou2ApBgZiu5WuYJ4q8vg= 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 r13-6439] target/108738 - limit STV chain discovery X-Act-Checkin: gcc X-Git-Author: Richard Biener X-Git-Refname: refs/heads/master X-Git-Oldrev: 33ca5c92dfa7e2f591a838bb768d9d6eea56793b X-Git-Newrev: 6010189923908501ca5b02bd1f4aee05d2283118 Message-Id: <20230303073150.5AE843858D33@sourceware.org> Date: Fri, 3 Mar 2023 07:31:50 +0000 (GMT) List-Id: https://gcc.gnu.org/g:6010189923908501ca5b02bd1f4aee05d2283118 commit r13-6439-g6010189923908501ca5b02bd1f4aee05d2283118 Author: Richard Biener Date: Thu Mar 2 13:43:51 2023 +0100 target/108738 - limit STV chain discovery The following puts a hard limit on the inherently quadratic STV chain discovery. Without a limit for the compiler.i testcase in PR26854 we see at -O2 machine dep reorg : 574.45 ( 53%) with release checking while with the proposed limit it's machine dep reorg : 2.86 ( 1%) PR target/108738 * config/i386/i386.opt (--param x86-stv-max-visits): New param. * doc/invoke.texi (--param x86-stv-max-visits): Document it. * config/i386/i386-features.h (scalar_chain::max_visits): New. (scalar_chain::build): Add bitmap parameter, return boolean. (scalar_chain::add_insn): Likewise. (scalar_chain::analyze_register_chain): Likewise. * config/i386/i386-features.cc (scalar_chain::scalar_chain): Initialize max_visits. (scalar_chain::analyze_register_chain): When we exhaust max_visits, abort. Also abort when running into any disallowed insn. (scalar_chain::add_insn): Propagate abort. (scalar_chain::build): Likewise. When aborting amend the set of disallowed insn with the insns set. (convert_scalars_to_vector): Adjust. Do not convert aborted chains. Diff: --- gcc/config/i386/i386-features.cc | 77 ++++++++++++++++++++++++++++------------ gcc/config/i386/i386-features.h | 10 ++++-- gcc/config/i386/i386.opt | 4 +++ gcc/doc/invoke.texi | 4 +++ 4 files changed, 70 insertions(+), 25 deletions(-) diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc index eff91301009..c09abf8fc20 100644 --- a/gcc/config/i386/i386-features.cc +++ b/gcc/config/i386/i386-features.cc @@ -296,6 +296,8 @@ scalar_chain::scalar_chain (enum machine_mode smode_, enum machine_mode vmode_) n_sse_to_integer = 0; n_integer_to_sse = 0; + + max_visits = x86_stv_max_visits; } /* Free chain's data. */ @@ -354,10 +356,12 @@ scalar_chain::mark_dual_mode_def (df_ref def) } /* Check REF's chain to add new insns into a queue - and find registers requiring conversion. */ + and find registers requiring conversion. Return true if OK, false + if the analysis was aborted. */ -void -scalar_chain::analyze_register_chain (bitmap candidates, df_ref ref) +bool +scalar_chain::analyze_register_chain (bitmap candidates, df_ref ref, + bitmap disallowed) { df_link *chain; bool mark_def = false; @@ -371,6 +375,9 @@ scalar_chain::analyze_register_chain (bitmap candidates, df_ref ref) if (!NONDEBUG_INSN_P (DF_REF_INSN (chain->ref))) continue; + if (--max_visits == 0) + return false; + if (!DF_REF_REG_MEM_P (chain->ref)) { if (bitmap_bit_p (insns, uid)) @@ -381,6 +388,10 @@ scalar_chain::analyze_register_chain (bitmap candidates, df_ref ref) add_to_queue (uid); continue; } + + /* If we run into parts of an aborted chain discovery abort. */ + if (bitmap_bit_p (disallowed, uid)) + return false; } if (DF_REF_REG_DEF_P (chain->ref)) @@ -401,15 +412,19 @@ scalar_chain::analyze_register_chain (bitmap candidates, df_ref ref) if (mark_def) mark_dual_mode_def (ref); + + return true; } -/* Add instruction into a chain. */ +/* Add instruction into a chain. Return true if OK, false if the search + was aborted. */ -void -scalar_chain::add_insn (bitmap candidates, unsigned int insn_uid) +bool +scalar_chain::add_insn (bitmap candidates, unsigned int insn_uid, + bitmap disallowed) { if (!bitmap_set_bit (insns, insn_uid)) - return; + return true; if (dump_file) fprintf (dump_file, " Adding insn %d to chain #%d\n", insn_uid, chain_id); @@ -426,22 +441,27 @@ scalar_chain::add_insn (bitmap candidates, unsigned int insn_uid) df_ref ref; for (ref = DF_INSN_UID_DEFS (insn_uid); ref; ref = DF_REF_NEXT_LOC (ref)) if (!HARD_REGISTER_P (DF_REF_REG (ref))) - analyze_register_chain (candidates, ref); + if (!analyze_register_chain (candidates, ref, disallowed)) + return false; /* The operand(s) of VEC_SELECT don't need to be converted/convertible. */ if (def_set && GET_CODE (SET_SRC (def_set)) == VEC_SELECT) - return; + return true; for (ref = DF_INSN_UID_USES (insn_uid); ref; ref = DF_REF_NEXT_LOC (ref)) if (!DF_REF_REG_MEM_P (ref)) - analyze_register_chain (candidates, ref); + if (!analyze_register_chain (candidates, ref, disallowed)) + return false; + + return true; } /* Build new chain starting from insn INSN_UID recursively - adding all dependent uses and definitions. */ + adding all dependent uses and definitions. Return true if OK, false + if the chain discovery was aborted. */ -void -scalar_chain::build (bitmap candidates, unsigned insn_uid) +bool +scalar_chain::build (bitmap candidates, unsigned insn_uid, bitmap disallowed) { queue = BITMAP_ALLOC (NULL); bitmap_set_bit (queue, insn_uid); @@ -454,7 +474,17 @@ scalar_chain::build (bitmap candidates, unsigned insn_uid) insn_uid = bitmap_first_set_bit (queue); bitmap_clear_bit (queue, insn_uid); bitmap_clear_bit (candidates, insn_uid); - add_insn (candidates, insn_uid); + if (!add_insn (candidates, insn_uid, disallowed)) + { + /* If we aborted the search put sofar found insn on the set of + disallowed insns so that further searches reaching them also + abort and thus we abort the whole but yet undiscovered chain. */ + bitmap_ior_into (disallowed, insns); + if (dump_file) + fprintf (dump_file, "Aborted chain #%d discovery\n", chain_id); + BITMAP_FREE (queue); + return false; + } } if (dump_file) @@ -478,6 +508,8 @@ scalar_chain::build (bitmap candidates, unsigned insn_uid) } BITMAP_FREE (queue); + + return true; } /* Return a cost of building a vector costant @@ -2282,6 +2314,7 @@ convert_scalars_to_vector (bool timode_p) for (unsigned i = 0; i <= 2; ++i) { + auto_bitmap disallowed; bitmap_tree_view (&candidates[i]); while (!bitmap_empty_p (&candidates[i])) { @@ -2296,14 +2329,14 @@ convert_scalars_to_vector (bool timode_p) /* Find instructions chain we want to convert to vector mode. Check all uses and definitions to estimate all required conversions. */ - chain->build (&candidates[i], uid); - - if (chain->compute_convert_gain () > 0) - converted_insns += chain->convert (); - else - if (dump_file) - fprintf (dump_file, "Chain #%d conversion is not profitable\n", - chain->chain_id); + if (chain->build (&candidates[i], uid, disallowed)) + { + if (chain->compute_convert_gain () > 0) + converted_insns += chain->convert (); + else if (dump_file) + fprintf (dump_file, "Chain #%d conversion is not profitable\n", + chain->chain_id); + } delete chain; } diff --git a/gcc/config/i386/i386-features.h b/gcc/config/i386/i386-features.h index 00c2c5e8c2d..72a9f54b4e2 100644 --- a/gcc/config/i386/i386-features.h +++ b/gcc/config/i386/i386-features.h @@ -148,12 +148,15 @@ class scalar_chain /* Registers used in both vector and sclar modes. */ bitmap defs_conv; + /* Limit on chain discovery. */ + unsigned max_visits; + bitmap insns_conv; hash_map defs_map; unsigned n_sse_to_integer; unsigned n_integer_to_sse; - void build (bitmap candidates, unsigned insn_uid); + bool build (bitmap candidates, unsigned insn_uid, bitmap disallowed); virtual int compute_convert_gain () = 0; int convert (); @@ -168,8 +171,9 @@ class scalar_chain void convert_registers (); private: - void add_insn (bitmap candidates, unsigned insn_uid); - void analyze_register_chain (bitmap candidates, df_ref ref); + bool add_insn (bitmap candidates, unsigned insn_uid, bitmap disallowed); + bool analyze_register_chain (bitmap candidates, df_ref ref, + bitmap disallowed); virtual void convert_insn (rtx_insn *insn) = 0; virtual void convert_op (rtx *op, rtx_insn *insn) = 0; }; diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt index 7d57f617d65..94fdd639ff1 100644 --- a/gcc/config/i386/i386.opt +++ b/gcc/config/i386/i386.opt @@ -599,6 +599,10 @@ Target Mask(STV) Save Disable Scalar to Vector optimization pass transforming 64-bit integer computations into a vector ones. +-param=x86-stv-max-visits= +Target Joined UInteger Var(x86_stv_max_visits) Init(10000) IntegerRange(1, 1000000) Param +The maximum number of use and def visits when discovering a STV chain before the discovery is aborted. + mdispatch-scheduler Target RejectNegative Var(flag_dispatch_scheduler) Do dispatch scheduling if processor is bdver1, bdver2, bdver3, bdver4 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 0045661cc5d..2da68802356 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -16229,6 +16229,10 @@ The following choices of @var{name} are available on i386 and x86_64 targets: @item x86-stlf-window-ninsns Instructions number above which STFL stall penalty can be compensated. +@item x86-stv-max-visits +The maximum number of use and def visits when discovering a STV chain before +the discovery is aborted. + @end table @end table