From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-461286-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 4913 invoked by alias); 5 Sep 2014 10:51:44 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Received: (qmail 4878 invoked by uid 48); 5 Sep 2014 10:51:37 -0000
From: "paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/57248] string parameter to constexpr functions
Date: Fri, 05 Sep 2014 10:51:00 -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: 4.9.0
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: paolo.carlini at oracle dot com
X-Bugzilla-Status: NEW
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-57248-4-hs6WNYUiBi@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-57248-4@http.gcc.gnu.org/bugzilla/>
References: <bug-57248-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-09/txt/msg01120.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57248

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |paolo.carlini at oracle dot com

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> ---
It would be nice if Daniel could have another look to this, because his reduced
testcase in Comment #3 doesn't work anymore as a reproducer, is simply accepted
by eg, the released 4.9.0.

Also, I note that all the compilers I have at hand reject the original testcase
and also, eg:

constexpr bool strmatch(const char *s1, const char *s2)
{
  return (*s1==*s2) ? 
            (*s1=='\0') ? 
               true
               : strmatch(s1+1, s2+1) 
            : false;
}

template <unsigned N>
constexpr int index(const char (&array)[N])
{
  return strmatch(array, "m0") ? 0 : -1;
}

template <int N>
constexpr int get() { return 1; }

template<unsigned N>
constexpr int extract(const char (&array)[N]) {
  return get<index(array)>();
}

int main(void)
{
  constexpr int i = strmatch("m0", "m0");  // OK
  constexpr int j = index("m0");  // OK
  constexpr int k = extract("m0"); // Not OK
}