From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 6E732385842A; Sat, 30 Dec 2023 18:01:32 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6E732385842A
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1703959292;
	bh=0J2hZFbSRn+ribglSJx2hZlXc+zIYrhPt/ZcHOSxmyM=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=wBnlMfEKqlGkuTqJ6lDBr5VVMHyRx1eaRnIlbSbpzxv4eVl4qCTUi91uPdnZUDCoH
	 BkKbBkY/ULALTKTdAnwVYSRwT7UCTT6DkhEZsEUBD7jgllgRoBw/AicTNW7s/kbbtb
	 2fUtpDte1+tV4vlE78OpQz57rDpcD5TZiQDpI9wM=
From: "hp at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/113175] [14 Regression]
 testsuite/std/ranges/iota/max_size_type.cc 5x times slower
Date: Sat, 30 Dec 2023 18:01:31 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: hp at gcc dot gnu.org
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cf_gcctarget short_desc component
Message-ID: <bug-113175-4-dezUfIzNaf@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-113175-4@http.gcc.gnu.org/bugzilla/>
References: <bug-113175-4@http.gcc.gnu.org/bugzilla/>
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: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113175

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|mmix-knuth-mmixware         |mmix-knuth-mmixware,
                   |                            |x86_64-linux-gnu
            Summary|[14 Regression] MMIX:       |[14 Regression]
                   |testsuite/std/ranges/iota/m |testsuite/std/ranges/iota/m
                   |ax_size_type.cc 5x times    |ax_size_type.cc 5x times
                   |slower                      |slower
          Component|target                      |libstdc++

--- Comment #1 from Hans-Peter Nilsson <hp at gcc dot gnu.org> ---
I'm afraid this isn't target-specific.
I bootstrapped native x86_64-linux-gnu off the both source trees, and ran \=
time
env LD_LIBRARY_PATH=3D(long curse) ./max_size_type.exe

r12-2797-g307e0d40367996:
0.32user 0.00system 0:00.32elapsed 99%CPU (0avgtext+0avgdata 2620maxresiden=
t)k
0inputs+0outputs (0major+184minor)pagefaults 0swaps

r14-6859-gd1eacedc6d9b:
1.73user 0.00system 0:01.73elapsed 100%CPU (0avgtext+0avgdata 3564maxreside=
nt)k
0inputs+0outputs (0major+194minor)pagefaults 0swaps

...which is a factor of about 5.4, consistent with the MMIX observation.
Still unknown whether libstdc++ or code-generator of course, but I'm leaning
towards the latter, for the same reasons as in the precious comment.  Maybe=
 the
test-case triggers peculiar details.=