[Bug c++/54126] New: ICE on constexpr move ctor with const ref type instead of error

[Bug c++/54126] New: ICE on constexpr move ctor with const ref type instead of error

[morpheby at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

             Bug #: 54126
           Summary: ICE on constexpr move ctor with const ref type instead
                    of error
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: morpheby@gmail.com


Compiling attached source fails with ICE:
$ gcc -std=c++11 gcc-bug.cpp --save-temps
gcc-bug.cpp: In instantiation of 'constexpr ClassA<T1>::ClassA(U1&&) [with U1 =
int; T1 = const ClassB&]':
gcc-bug.cpp:34:3:   required from here
gcc-bug.cpp:22:12: internal compiler error: in
build_data_member_initialization,
 at cp/semantics.c:5790

GCC version dump: $ gcc -v
Using built-in specs.
COLLECT_GCC=C:\MinGW\bin\gcc.exe
COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/i686-w64-mingw32/4.7.2/lto-wrapp
er.exe
Target: i686-w64-mingw32
Configured with: ../..//mingw-src/gcc-4_7-branch/configure
--host=i686-w64-mingw
32 --build=i686-w64-mingw32 --target=i686-w64-mingw32
--prefix=/mingw-gcc-4_7-br
anch-x32 --with-sysroot=/mingw-gcc-4_7-branch-x32 --enable-shared
--enable-stati
c --enable-targets=all --enable-multilib --enable-languages=c,c++,fortran,lto
--
enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-lto
-
-enable-graphite --enable-cloog-backend=isl --enable-checking=release
--enable-f
ully-dynamic-string --enable-version-specific-runtime-libs
--enable-sjlj-excepti
ons --disable-ppl-version-check --disable-cloog-version-check
--disable-libstdcx
x-pch --disable-libstdcxx-debug --disable-bootstrap --disable-rpath
--disable-wi
n32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-ld
--wi
th-tune=generic --with-host-libstdcxx='-static -lstdc++' --with-libiconv
--with-
gmp=/mingw-gcc-4_7-branch-libs-x32 --with-mpfr=/mingw-gcc-4_7-branch-libs-x32
--
with-mpc=/mingw-gcc-4_7-branch-libs-x32
--with-ppl=/mingw-gcc-4_7-branch-libs-x3
2 --with-cloog=/mingw-gcc-4_7-branch-libs-x32 --with-pkgversion='MinGW-builds:
h
ttp://sourceforge.net/projects/mingwbuilds/'
--with-bugurl=http://sourceforge.ne
t/projects/mingwbuilds/ CFLAGS='-O2 -pipe -fomit-frame-pointer
-momit-leaf-frame
-pointer -I/mingw-gcc-4_7-branch-libs-x32/include' CXXFLAGS='-O2 -pipe
-fomit-fr
ame-pointer -momit-leaf-frame-pointer' CPPFLAGS= LDFLAGS='-pipe -s
-L/mingw-gcc-
4_7-branch-libs-x32/lib -L/mingw-gcc-4_7-branch-x32/bin'
Thread model: posix
gcc version 4.7.2 20120727 (prerelease) (MinGW-builds:
http://sourceforge.net/pr
ojects/mingwbuilds/)

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-30 14:22:18 UTC ---
The attachment is missing

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[morpheby at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

--- Comment #2 from Ilya Mikhaltsou <morpheby at gmail dot com> 2012-07-30 14:33:41 UTC ---
Created attachment 27896
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27896
Preprocessed source

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-07-30
     Ever Confirmed|0                           |1

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[morpheby at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

--- Comment #3 from Ilya Mikhaltsou <morpheby at gmail dot com> 2012-07-30 14:56:31 UTC ---
Reduced source:

namespace std {
template<class _E> class initializer_list {
};
}
using namespace std;

class ClassB {
public:
   constexpr ClassB(int x) {}
};

template<class T1> struct ClassA {
   template<class U1> constexpr ClassA(U1 &&a)
      : a_(a) {}
   T1 a_;
};

void f(std::initializer_list<ClassA<const ClassB&>> l) {
   f({
      {1}
   });
}

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[freddie_chopin at op dot pl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

--- Comment #4 from Freddie Chopin <freddie_chopin at op dot pl> 2013-02-13 07:29:23 UTC ---
Created attachment 29430
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29430
simple fail case

I think I have an even simplier test case, I guess it's the same problem (at
least the ICE message matches). I also think that bug 51707 is actually the
same problem.

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[morpheby at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

--- Comment #5 from Ilya Mikhaltsou <morpheby at gmail dot com> 2013-02-13 12:20:21 UTC ---
(In reply to comment #4)
> Created attachment 29430 [details]
> simple fail case
> 
> I think I have an even simplier test case, I guess it's the same problem (at
> least the ICE message matches). I also think that bug 51707 is actually the
> same problem.

Yes, looks like both mine and yours testcase actually do the same - they
attempt to move some constexpr to another, and gcc fails. That looks like not
implemented or buggy check for error.

bug 51707 looks to be error on correct code and possibly fails on getting
constant l-value reference.

If they are exactly the same, then the bug actually lies in contexpr reference
mechanics, and gcc fails on getting constexpr reference of any kind, not on
moving constexpr. I'll try to investigate if it is the case as soon as I have
some free time.

[Bug c++/54126] ICE on constexpr move ctor with const ref type instead of error

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54126

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to work|                            |4.8.0, 4.9.1, 5.0
         Resolution|---                         |FIXED

--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Fixed long time ago. ICEs with improperly reduced testcases involving
std::initializer_list (per Comment #3) are fixed in mainline (Dup of c++/60848,
c++/61723).