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 541963858D1E; Sun, 19 Mar 2023 01:46:09 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 541963858D1E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1679190369;
	bh=0z+5WZhB1IH0jc992AwpDy3LmV8+pWMHOCjW9dLkfww=;
	h=From:To:Subject:Date:From;
	b=W6Oo6ovOTiII1c1LYyvoWJfR73NexyeQhb6qk41IuRLGG4OMrUcb7tpk+Qd5ShgAU
	 Htet39IlWnjXJWSAY/Slip5gWAQzWi3GciCETBnoZ0Et/DnElCtpb3gHBbuYwju2rM
	 Vb9cPSF/ETxVunTnD+kp8dY+b15koVA/MV7tqoYw=
From: "john.harper at vuw dot ac.nz" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/109186] New: nearest(huge(x),-1.0_kind(x)) half of
 correct value
Date: Sun, 19 Mar 2023 01:46:07 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 12.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: john.harper at vuw dot ac.nz
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: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-109186-4@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=3D109186

            Bug ID: 109186
           Summary: nearest(huge(x),-1.0_kind(x)) half of correct value
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: john.harper at vuw dot ac.nz
  Target Milestone: ---

With all four real kinds available in gfortran_12 nearest(x,y) with x =3D h=
uge
and y =3D -1 this program gave about half the correct result. Ifort gave co=
rrect
results for the 3 different kinds it has: sp,dp,qp.

The program:

  implicit none
  integer,parameter::sp =3D kind(1.0), dp=3Dkind(1d0), ncases =3D 2, &
       ep =3D selected_real_kind(18),qp =3D selected_real_kind(33)
  character(*),parameter:: fmt(4) =3D &
       "(A,ES"//["16.08E2","26.17E3","30.20E4","44.34E4"]//")"
  character(24),dimension(2):: splist,dplist,eplist,qplist=20
  integer n
  real(sp),parameter::sp1 =3D 1.0_sp
  real(sp):: spx(ncases) =3D [huge(sp1),nearest(huge(sp1),-sp1)]
  data splist/'huge(sp1)','nearest(huge(sp1),-sp1)'/
  real(dp),parameter::dp1 =3D 1.0_dp
  real(dp):: dpx(ncases) =3D [huge(dp1),nearest(huge(dp1),-dp1)]
  data dplist/'huge(dp1)','nearest(huge(dp1),-dp1)'/
  real(ep),parameter::ep1 =3D 1.0_ep
  real(ep):: epx(ncases) =3D [huge(ep1),nearest(huge(ep1),-ep1)]
  data eplist/'huge(ep1)','nearest(huge(ep1),-ep1)'/
  real(qp),parameter::qp1 =3D 1.0_qp
  real(qp):: qpx(ncases) =3D [huge(qp1),nearest(huge(qp1),-qp1)]
  data qplist/'huge(qp1)','nearest(huge(qp1),-qp1)'/

  print fmt(1),(splist(n),spx(n),n=3D1,ncases)
  print fmt(2),(dplist(n),dpx(n),n=3D1,ncases)
  print fmt(3),(eplist(n),epx(n),n=3D1,ncases)
  print fmt(4),(qplist(n),qpx(n),n=3D1,ncases)
end program

The output on ubuntu (Linux 86_64)
huge(sp1)                 3.40282347E+38
nearest(huge(sp1),-sp1)   1.70141173E+38
huge(dp1)                 1.79769313486231571E+308
nearest(huge(dp1),-dp1)   8.98846567431157854E+307
huge(ep1)                 1.18973149535723176502E+4932
nearest(huge(ep1),-ep1)   5.94865747678615882511E+4931
huge(qp1)                 1.1897314953572317650857593266280070E+4932
nearest(huge(qp1),-qp1)   5.9486574767861588254287966331400351E+4931=