Re: c++/9338: ICE in peculiar templated constructors

Re: c++/9338: ICE in peculiar templated constructors

[Giovanni Bajo]

The following reply was made to PR c++/9338; it has been noted by GNATS.

From: "Giovanni Bajo" <giovannibajo@libero.it>
To: <gcc-gnats@gcc.gnu.org>,
	<gcc-bugs@gcc.gnu.org>,
	<martin@xemacs.org>,
	<nobody@gcc.gnu.org>,
	<gcc-prs@gcc.gnu.org>
Cc: "Wolfgang Bangerth" <bangerth@ices.utexas.edu>
Subject: Re: c++/9338: ICE in peculiar templated constructors
Date: Mon, 7 Apr 2003 12:50:17 +0200

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&p
 r=9338
 
 Reconfirmed today on 2.95 -> 3.3 (bump [date] please).
 
 Giovanni Bajo
 

Re: c++/9338: ICE in peculiar templated constructors

[bangerth]

Synopsis: ICE in peculiar templated constructors

State-Changed-From-To: open->analyzed
State-Changed-By: bangerth
State-Changed-When: Thu Jan 16 07:12:02 2003
State-Changed-Why:
    Confirmed. A smaller testcase is this:
    -------------------------
    struct Bool {
        template <bool> struct CC { typedef int Int; };
    
        template <typename> struct S1 { enum { value = true }; };
        template <typename> struct S2 { enum { value = false }; };
    
        template <typename T>
        Bool (T x, typename CC<S1<T>::value>::Int = 0);
    
        template <typename T>
        Bool (T x, typename CC<!S2<T>::value>::Int = 0);
    };
    
    int main () {
      Bool b (1);
    }
    --------------------------------------
    Note that the second type of the two overloads of the
    constructor resolve to the same type, int.
    
    This code crashes gcc since at least 2.95:
    g/a> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc
    x.cc: In function `int main()':
    x.cc:15: internal compiler error: Segmentation fault
    Please submit a full bug report,
    with preprocessed source if appropriate.
    See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.
    
    W.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=9338

c++/9338: ICE in peculiar templated constructors

[martin]

>Number:         9338
>Category:       c++
>Synopsis:       ICE in peculiar templated constructors
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Thu Jan 16 01:36:01 PST 2003
>Closed-Date:
>Last-Modified:
>Originator:     Martin Buchholz
>Release:        gcc-3.2.1
>Organization:
>Environment:
Linux x86
>Description:
The file below results in ICE

g++   main.cc -o main
main.cc: In function `int main(int, char**)':
main.cc:36: internal error: Segmentation fault
Please submit a full bug report,

The file compiles (with warnings) under icc, 
but fails to link.

------------------------------------------------------
class Bool
{
public:
  const bool val_;
  template <class T, bool condition> struct Constraint;
  template <class T> struct Constraint<T,true> { typedef int Dummy; };
  template <typename T> struct Convertible { enum { value = true }; };
  template <typename T>
  explicit
  Bool (T x, typename Constraint<T, Convertible<T>::value>::Dummy = 0)
    : val_ (bool (x))
  {}
  template <class T> struct Unlikely { enum { value = false }; };
  template <typename T>
  explicit
  Bool (T x, typename Constraint<T, ! Convertible<T>::value>::Dummy = 0);
  template <typename T>
  Bool (T x, typename Constraint<T, ! Unlikely<T>::value>::Dummy = 0);
  Bool (bool val)         : val_ (val)        {}
  Bool (const Bool & val) : val_ (bool (val)) {}
  struct S_ { int M_; };
  operator int S_::*  () const { return val_ ? & S_::M_ : 0; }
};

struct X
{
  bool b;
  X (bool x) : b (x) {}
  struct S_ { int M_; };
  operator int S_::*  () const { return b ? & S_::M_ : 0; }
};

int
main (int argc, char *argv[])
{
  Bool b (X (true));
}
>How-To-Repeat:
g++   main.cc -o main
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: