From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) by sourceware.org (Postfix) with ESMTPS id 898C63858CDA for ; Tue, 16 Aug 2022 14:12:16 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 898C63858CDA Received: by mail-ed1-x531.google.com with SMTP id t5so13640721edc.11 for ; Tue, 16 Aug 2022 07:12:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=po5aF8OBMnv3wQRnzDSqAsLFycGUhbjo3nKbBz2Yf/s=; b=m8+76oh4h172gXVkgUh+0ezUQPrneCHYp5C6fF4wDjALSPz/QEcWzUoqEeEDsGXTm8 vKeivbtckg38L7glgSRC8LQUoeHNSTbSxk3SANe9dLkTrE/t25v2MfsQSa8nBGaKVrIn NxUoYtU5uGEH5IF1PWGZxiNLkYXOwLosZoTsGI4f8qqcG+h56xi40G+QorHa/SGdxHDV WrSmHOslF357ByjAoczzsBQmHfrUCpZ3CrzJkR/suPXNIknhCfn512k78su0n4yTISot 6VFV4Kmge2Vw8fwd1dAEeM8Tts/O57qJgnrgIbsSXqQpvMEfExQr0z3XvBjD/h5Hlc3O XoDQ== X-Gm-Message-State: ACgBeo3cELnIe9S6hEvCbdG//OtlTYrBwEQnm5aFDPj8bkBxVEFWmfw2 /z+0hkLoLNwddsCM38LH7WA5tQHNP+D4M79tshY= X-Google-Smtp-Source: AA6agR6xBZTN1E7nvJyyoBrk8N7ImN1BF1JmAPWiTTExNK+sI1QzBMDr5Xc9BCcNE84KM/EsVfJ8jL3N1VAobiG23tg= X-Received: by 2002:a05:6402:270d:b0:43a:67b9:6eea with SMTP id y13-20020a056402270d00b0043a67b96eeamr18629088edd.94.1660659134874; Tue, 16 Aug 2022 07:12:14 -0700 (PDT) MIME-Version: 1.0 References: <20220816135930.225960-1-aldyh@redhat.com> In-Reply-To: <20220816135930.225960-1-aldyh@redhat.com> From: Richard Biener Date: Tue, 16 Aug 2022 16:12:02 +0200 Message-ID: Subject: Re: [PATCH] Avoid further recomputations in path_range_query once path is finalized. To: Aldy Hernandez Cc: Andrew MacLeod , GCC patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Aug 2022 14:12:19 -0000 On Tue, Aug 16, 2022 at 3:59 PM Aldy Hernandez wrote: > > [Richi, I'm trying to make things more obvious for others working for the > cose base. What do you think?] > > This makes a few things explicit to avoid misuse. First, we add a > flag to differentiate between a path whose depdenency ranges are being > computed, and a path that is finalized and no further calculations > should be done. I've also enhanced the comments to document what > queries are supported. Finally, I added some asserts to make sure > range_of_expr is only used on the final conditional once the path has > been finalized. > > Unfortunately, the forward threader builds dummy statements it passes > to the path solver. Most of these don't have a BB associated with > them. I've cleared the BB field for the one that still had one, to > make the asserts above work. > > No difference in thread counts over my cc1 .ii files. > > gcc/ChangeLog: > > * gimple-range-path.cc (path_range_query::path_range_query): > Initialized m_path_finalized. > (path_range_query::internal_range_of_expr): Avoid further > recomputations once path is finalized. > Take basic_block instead of stmt as argument. > (path_range_query::range_of_expr): Document. Add asserts. > (path_range_query::compute_ranges): Set m_path_finalized. > * gimple-range-path.h (path_range_query::internal_range_of_expr): > Replace statement argument with basic block. > (class path_range_query): Add m_path_finalized. > * tree-ssa-threadedge.cc > (jump_threader::simplify_control_stmt_condition): Clear BB field > in dummy_switch. > --- > gcc/gimple-range-path.cc | 50 ++++++++++++++++++++++++++++++++++---- > gcc/gimple-range-path.h | 7 +++++- > gcc/tree-ssa-threadedge.cc | 1 + > 3 files changed, 52 insertions(+), 6 deletions(-) > > diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc > index c99d77dd340..a8412dd090b 100644 > --- a/gcc/gimple-range-path.cc > +++ b/gcc/gimple-range-path.cc > @@ -40,7 +40,8 @@ path_range_query::path_range_query (bool resolve, gimple_ranger *ranger) > : m_cache (new ssa_global_cache), > m_has_cache_entry (BITMAP_ALLOC (NULL)), > m_resolve (resolve), > - m_alloced_ranger (!ranger) > + m_alloced_ranger (!ranger), > + m_path_finalized (false) > { > if (m_alloced_ranger) > m_ranger = new gimple_ranger; > @@ -159,7 +160,7 @@ path_range_query::range_on_path_entry (vrange &r, tree name) > // Return the range of NAME at the end of the path being analyzed. > > bool > -path_range_query::internal_range_of_expr (vrange &r, tree name, gimple *stmt) > +path_range_query::internal_range_of_expr (vrange &r, tree name, basic_block bb) > { > if (!r.supports_type_p (TREE_TYPE (name))) > return false; > @@ -174,8 +175,16 @@ path_range_query::internal_range_of_expr (vrange &r, tree name, gimple *stmt) > return true; > } > > - if (stmt > - && range_defined_in_block (r, name, gimple_bb (stmt))) > + // Avoid further recomputations once the path has been finalized. > + if (m_path_finalized) > + { > + gimple_range_global (r, name); I suppose we can't assert here instead? > + return true; > + } > + > + // We're being called as part of the calculation of ranges for exit > + // dependencies. Set the cache as we traverse the path top-down. > + if (bb && range_defined_in_block (r, name, bb)) > { > if (TREE_CODE (name) == SSA_NAME) > { > @@ -192,10 +201,37 @@ path_range_query::internal_range_of_expr (vrange &r, tree name, gimple *stmt) > return true; > } > > +// This, as well as range_of_stmt, are the main entry points for > +// making queries about a path. > +// > +// Once the ranges for the exit dependencies have been pre-calculated, > +// the path is considered finalized, and the only valid query is > +// asking the range of a NAME at the end of the path. > +// > +// Note that this method can also be called internally before the path > +// is finalized, as part of the path traversal pre-calculating the > +// ranges for exit dependencies. In this case, it may be called on > +// statements that are not the final conditional as described above. > + > bool > path_range_query::range_of_expr (vrange &r, tree name, gimple *stmt) > { > - if (internal_range_of_expr (r, name, stmt)) > + basic_block bb = stmt ? gimple_bb (stmt) : NULL; > + > + // Once a path is finalized, the only valid queries are of the final > + // statement in the exit block. why? shouldn't we support queries for all dependent ranges (what the user specified as imports argument to compute_ranges)? If we want to restrict things this way shouldn't we simply not expose this function but instead just path_range_query::range_of_exit, or even what the threader uses as find_taken_edge? The loop header copying case would also work with this, it's interested in the known outgoing edge of the path. > + if (flag_checking && m_path_finalized && stmt) > + { > + // The forward threader may query dummy statements without a > + // basic block. > + if (bb) > + { > + gcc_assert (stmt == last_stmt (bb)); > + gcc_assert (bb == exit_bb ()); > + } > + } > + > + if (internal_range_of_expr (r, name, bb)) > { > if (r.undefined_p ()) > m_undefined_path = true; > @@ -608,6 +644,7 @@ path_range_query::compute_ranges (const vec &path, > > set_path (path); > m_undefined_path = false; > + m_path_finalized = false; > > if (dependencies) > bitmap_copy (m_exit_dependencies, dependencies); > @@ -642,6 +679,7 @@ path_range_query::compute_ranges (const vec &path, > > move_next (); > } > + m_path_finalized = true; > > if (DEBUG_SOLVER) > { > @@ -730,6 +768,8 @@ jt_fur_source::query_relation (tree op1, tree op2) > } > > // Return the range of STMT at the end of the path being analyzed. > +// > +// See notes in range_of_expr as to what are considered valid queries. > > bool > path_range_query::range_of_stmt (vrange &r, gimple *stmt, tree) > diff --git a/gcc/gimple-range-path.h b/gcc/gimple-range-path.h > index 3cb794e34a9..61a7d0f656e 100644 > --- a/gcc/gimple-range-path.h > +++ b/gcc/gimple-range-path.h > @@ -46,7 +46,7 @@ public: > void debug (); > > private: > - bool internal_range_of_expr (vrange &r, tree name, gimple *); > + bool internal_range_of_expr (vrange &r, tree name, basic_block); > bool defined_outside_path (tree name); > void range_on_path_entry (vrange &r, tree name); > path_oracle *get_path_oracle () { return (path_oracle *)m_oracle; } > @@ -113,6 +113,11 @@ private: > // True if m_ranger was allocated in this class and must be freed at > // destruction. > bool m_alloced_ranger; > + > +// Once the ranges for the exit dependencies have been pre-calculated, > +// the path is considered finalized and this is set to TRUE. > +// Otherwise, the path is being analyzed. > + bool m_path_finalized; > }; > > #endif // GCC_TREE_SSA_THREADSOLVER_H > diff --git a/gcc/tree-ssa-threadedge.cc b/gcc/tree-ssa-threadedge.cc > index e64e4f209f7..213796c10cc 100644 > --- a/gcc/tree-ssa-threadedge.cc > +++ b/gcc/tree-ssa-threadedge.cc > @@ -451,6 +451,7 @@ jump_threader::simplify_control_stmt_condition (edge e, gimple *stmt) > possible, the simplified value will be a CASE_LABEL_EXPR of > the label that is proven to be taken. */ > gswitch *dummy_switch = as_a (gimple_copy (stmt)); > + gimple_set_bb (dummy_switch, NULL); I think it's not wrong to say the stmt is in the block though > gimple_switch_set_index (dummy_switch, cached_lhs); > cached_lhs = m_simplifier->simplify (dummy_switch, stmt, e->src, > m_state); > -- > 2.37.1 >