From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 9FC063858D39; Mon, 26 Jun 2023 17:50:54 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9FC063858D39 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1687801854; bh=nZh2nKaXg3XdI7ZNH3qyStCgxUoUc0N17a/NJHCObCM=; h=From:To:Subject:Date:In-Reply-To:References:From; b=DVW0jQa6XHXdyVU29FhbhBIALkUHCX0Q/UwQU440Z1unMDvp4BYHhXKqacu3wMKOn 9L6oXrlAZQHuzTQyrDCB+LzrG8N7+cgTLQ/QJ9E6FQ8YqKHGX6oaEbZDDgyQg8iyN+ s3YerCPehNNKoMDgazSgfEzWrozOyAftFDsUPyYI= From: "hubicka at ucw dot cz" To: gcc-bugs@gcc.gnu.org Subject: [Bug ipa/110334] [13/14 Regresssion] unused functions not eliminated before LTO streaming Date: Mon, 26 Jun 2023 17:50:52 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: ipa X-Bugzilla-Version: 13.1.1 X-Bugzilla-Keywords: lto, missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: hubicka at ucw dot cz X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 13.2 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110334 --- Comment #11 from Jan Hubicka --- Hi, what about this. It should make at least quite basic inlining to happen to always_inline. I do not think many critical always_inlines have indirect calls in them. The test for lto is quite bad and I can work on solving this incrementally (it would be nice to have this tested and possibly backport it). diff --git a/gcc/ipa-inline.cc b/gcc/ipa-inline.cc index efc8df7d4e0..dcec07e49e1 100644 --- a/gcc/ipa-inline.cc +++ b/gcc/ipa-inline.cc @@ -702,6 +702,38 @@ can_early_inline_edge_p (struct cgraph_edge *e) if (!can_inline_edge_p (e, true, true) || !can_inline_edge_by_limits_p (e, true, false, true)) return false; + /* When inlining regular functions into always-inline functions + during early inlining watch for possible inline cycles. */ + if (DECL_DISREGARD_INLINE_LIMITS (caller->decl) + && lookup_attribute ("always_inline", DECL_ATTRIBUTES (caller->decl)) + && (!DECL_DISREGARD_INLINE_LIMITS (callee->decl) + || !lookup_attribute ("always_inline", DECL_ATTRIBUTES (callee->decl)))) + { + /* If there are indirect calls, inlining may produce direct call. + TODO: We may lift this restriction if we avoid errors on formely + indirect calls to always_inline functions. Taking address + of always_inline function is generally bad idea and should + have been declared as undefined, but sadly we allow this. */ + if (caller->indirect_calls || e->callee->indirect_calls) + return false; + for (cgraph_edge *e2 =3D callee->callees; e2; e2 =3D e2->next_callee) + { + struct cgraph_node *callee2 =3D e2->callee->ultimate_alias_target= (); + /* As early inliner runs in RPO order, we will see uninlined + always_inline calls only in the case of cyclic graphs. */ + if (DECL_DISREGARD_INLINE_LIMITS (callee2->decl) + || lookup_attribute ("always_inline", callee2->decl)) + return false; + /* With LTO watch for case where function is later replaced + by always_inline definition. + TODO: We may either stop treating noninlined cross-module alwa= ys + inlines as errors, or we can extend decl merging to produce + syntacic alias and honor always inline only in units it has + been declared as such. */ + if (flag_lto && callee2->externally_visible) + return false; + } + } return true; } @@ -3034,18 +3066,7 @@ early_inliner (function *fun) if (!optimize || flag_no_inline - || !flag_early_inlining - /* Never inline regular functions into always-inline functions - during incremental inlining. This sucks as functions calling - always inline functions will get less optimized, but at the - same time inlining of functions calling always inline - function into an always inline function might introduce - cycles of edges to be always inlined in the callgraph. - - We might want to be smarter and just avoid this type of inlining. = */ - || (DECL_DISREGARD_INLINE_LIMITS (node->decl) - && lookup_attribute ("always_inline", - DECL_ATTRIBUTES (node->decl)))) + || !flag_early_inlining) ; else if (lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) !=3D NULL)=