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 219243858C62; Mon, 27 Mar 2023 17:07:42 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 219243858C62
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1679936862;
	bh=U7Lx9ZvXwgCml0LMeMTqCP2ANUX1oNtL6EkIucM+JN0=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=Q/WI8QhQwob1DmGhNYmk1hhpgjSvzu2DLj+mAwFKpwTgZeiLiPsqfk6agyXZ/x7Vc
	 Zs0d/7mHa1qLZpMTYCYjdUjhjDsjuHXMo4dzRyoIAuytONmNPMo7R0Zryep05mUQjn
	 CZn9DhPJA6LH2G93hJZMhVfJkyMIkx477BJN5ATk=
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109154] [13 regression] jump threading
 de-optimizes nested floating point comparisons
Date: Mon, 27 Mar 2023 17:07:40 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jakub at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 13.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: attachments.created
Message-ID: <bug-109154-4-UFacTDiWXc@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109154-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109154-4@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=3D109154

--- Comment #21 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 54770
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D54770&action=3Dedit
gcc13-pr109154.patch

So what about this then?
It matches the x86 FTZ behavior, because FTZ is a masked reaction to underf=
low
exception, so for operations like comparisons nothing is flushed to zero nor
comparing as it was flushed to zero.
But no idea what e.g. Alpha will do, if it has in hardware support for
comparisons including denormals...=