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 1A3F2385CDC6; Thu, 30 Mar 2023 11:09:45 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1A3F2385CDC6
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1680174585;
	bh=zaBebqj09ofm5GD21QBBK5Lt/imVcJjdmciTUPtEpak=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=q6I40hHjIRarWNYGLV8MP0UwDpNkmlz9ZQfy/Xhfoz/etcWFN364JmWkw6lfiXDCN
	 RfW+KaGBupNGZ4ghl1/Az6pxZ29/YedUSwpSNAI9TxTUcAKyaTVDnCw2JOJX98hwS+
	 VcQWNN677CZAU20fshGNyfIG62NIHGzpTUDBUaZI=
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/109344] feraiseexcept produces incorrect code when
 optimizations are enabled
Date: Thu, 30 Mar 2023 11:09:44 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: unknown
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jakub 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: cc
Message-ID: <bug-109344-4-lA6Z8YMfca@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109344-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109344-4@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=3D109344

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I get the same result for all of -O0/-O1/-O2, all 3 functions raise both
exceptions and that is correct, glibc has removed the inline versions some =
time
ago:
https://sourceware.org/pipermail/libc-alpha/2020-March/111753.html

The bug was on the glibc side:
both the
      /* One example of an invalid operation is 0.0 / 0.0.  */
      float __f =3D 0.0;

# ifdef __SSE_MATH__
      __asm__ __volatile__ ("divss %0, %0 " : : "x" (__f));
and
      float __f =3D 1.0;
      float __g =3D 0.0;

# ifdef __SSE_MATH__
      __asm__ __volatile__ ("divss %1, %0" : : "x" (__f), "x" (__g));
part, because glibc didn't tell the compiler the inline assembly actually
modifies the register.
So, the first one was supposed to be
      __asm__ __volatile__ ("divss %0, %0 " : "+x" (__f));
and the second
      __asm__ __volatile__ ("divss %1, %0" : "+x" (__f) : "x" (__g));
Not a bug on the GCC side and on glibc side it has been fixed by the remova=
l of
the inline version.=