[Bug c++/37404] New: ICE on va_arg and template deduction

[Bug c++/37404] New: ICE on va_arg and template deduction

[sebor at roguewave dot com]

gcc 4.3.1 gets an ICE on the program below. I didn't try 4.3.2 or 4.4.0.

$ cat t.C && gcc t.C
#include <stdarg.h>
#include <string.h>

const char* foobar (void*) { return 0; }

template <class> struct S { static const char* foo () { return 0; } };
template <class T, int N>
struct S<T [N]> { static const char* foo () { return foobar (T ()); } };

int main () {
    va_list va;
    memset (&va, 0, sizeof va);

    S<va_list>::foo ();
}
t.C: In static member function 'static const char* S<T [N]>::foo() [with T =
__va_list_tag, int N = 1]':
t.C:14:   instantiated from here
t.C:8: internal compiler error: in build_special_member_call, at cp/call.c:5325
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: ICE on va_arg and template deduction
           Product: gcc
           Version: 4.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sebor at roguewave dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37404

[Bug c++/37404] ICE on va_arg and template deduction

[pinskia at gcc dot gnu dot org]

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------- Comment #1 from pinskia at gcc dot gnu dot org  2008-09-07 00:34 -------
This only ICEs on targets where va_list is an array.
Reduced testcase:
typedef __builtin_va_list __gnuc_va_list;
typedef __gnuc_va_list va_list;
template <class> struct S { static const char* foo () { return 0; } };
template <class T, int N>
struct S<T [N]> { static const char* foo () { return foobar (T ()); } };
int main () {
   S<va_list>::foo ();
}

--- CUT ---
It does not ICE for powerpc64-linux-gnu but does for spu-elf and
powerpc-linux-gnu.

With 4.1.1, I get the following error message:
t.cc: In static member function ‘static const char* S<T [N]>::foo() [with T =
__va_list_tag, int N = 1]’:
t.cc:6:   instantiated from here
t.cc:4: error: invalid cast from type ‘int’ to type ‘__va_list_tag’

Also Note I don't think this is valid code.
If we change the template to:
struct S<T [N]> { static const char* foo () { return new T (); } };

I get an ICE even with 4.1.1:
t.cc: In static member function ‘static const char* S<T [N]>::foo() [with T =
__va_list_tag, int N = 1]’:
t.cc:6:   instantiated from here
t.cc:4: internal compiler error: in build_zero_init, at cp/init.c:260


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
 GCC target triplet|                            |x86_64-*-*, powerpc-linux-
                   |                            |gnu, spu-elf
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|0000-00-00 00:00:00         |2008-09-07 00:34:18
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37404