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 A0D7B385734E; Mon, 15 May 2023 14:00:14 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A0D7B385734E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1684159214;
	bh=qoc+FYeIX3GpDEJtGVsaYrSUCNWb8ylHzy68TwVgfC8=;
	h=From:To:Subject:Date:From;
	b=xApv7ucjTgQ2z9TlKyZEm8fxs2kWxa0EA8L37TnhSWTiV7499qS3ZjVikzx4m7WHN
	 qiB1fDdrGBsG+5H7aVDkKQVcdSG5AwtcCpKLH7KM5vPRs6+CEODzCuRgs0GDPlRq/w
	 IYva8KNnuHA2iOX9ncxiLWs2YkJXkwLfBiGMwMz0=
From: "brtnfld at hdfgroup dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/109861] New: Optimization is marking  uninitialized 
 C_PTR being passed to a C function, causes segfault.
Date: Mon, 15 May 2023 14:00:14 +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: 13.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: brtnfld at hdfgroup dot 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: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
 attachments.created
Message-ID: <bug-109861-4@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=3D109861

            Bug ID: 109861
           Summary: Optimization is marking  uninitialized  C_PTR being
                    passed to a C function, causes segfault.
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: brtnfld at hdfgroup dot org
  Target Milestone: ---

Created attachment 55085
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D55085&action=3Dedit
Fortran/C/Makfile. Changing the optimization level in the makefile reproduc=
es
the behaviour.

For a TYPE(C_PTR), INTENT(OUT), buf, which is being passed through a Fortran
subroutine to get the value set in a C function, an optimization of >=3D -O1
gives the warning "used uninitialized [-Wuninitialized]" and then the progr=
am
Segmentation faults - invalid memory reference. It works for gfortran 12 but
fails for gfortran 13 and 14. It works if the INTENT is INOUT.=