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 98DD33857340; Mon, 17 Oct 2022 16:13:22 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 98DD33857340
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1666023202;
	bh=55Ts8UNq5Ng+1PZY/MZZ46LjKVGszKlbwkODNpfY5ZY=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=X15DWQPETZ1TAht+38T9xWCkvJKYpfkUiXB/oKw24/l6bKQknpEn/ivhNuG8rXPK2
	 sCRvncqZJAqnPs28ovDSo4wHjsrSIVNjbcb2IbNlO9obqibtF6MKX5t8/f5wL/hvXH
	 6L9x0HdsagOFyrtEb2l23dKsPH60tCvZ6NaDAWGc=
From: "bartoldeman at users dot sourceforge.net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/107294] Missed optimization: multiplying real with
 complex number in Fortran (only)
Date: Mon, 17 Oct 2022 16:13:17 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 11.3.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: bartoldeman at users dot sourceforge.net
X-Bugzilla-Status: RESOLVED
X-Bugzilla-Resolution: FIXED
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: bug_status resolution
Message-ID: <bug-107294-4-PG8t7YUT2o@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107294-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107294-4@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=3D107294

bartoldeman at users dot sourceforge.net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from bartoldeman at users dot sourceforge.net ---
Thanks for the explanation, finding an example with NaNs you get
0.0 * (NaN + 0.0i) =3D NaN + 0.0i
for C with annex G.5.1
but
NaN + NaN i
for Fortran, unless you specify -fno-signed-zeros.

program main
  use, intrinsic :: ieee_arithmetic, only: IEEE_Value, IEEE_QUIET_NAN
  use, intrinsic :: iso_fortran_env, only: real32

  real(real32) :: a, nan
  complex(real32) :: cnan

  nan =3D IEEE_VALUE(nan, IEEE_QUIET_NAN)
  cnan =3D cmplx(nan, 0.0)
  zero =3D 0.0
  print *, zero, cnan, zero * cnan
end

illustrates this
   0.00000000     (             NaN,  0.00000000    ) (             NaN,=20=
=20=20=20=20=20=20
     NaN)
vs
   0.00000000     (             NaN,  0.00000000    ) (             NaN,=20
0.00000000    )=