Compiling with -m64 using attribute interrupt emits IRET not IRETQ

[Wink Saville]

I using hjl/interrupt/gcc-5-branch and my program is crashing when I
issue an INT xx. The problem appears to me to be that using
__attribute__ ((interrupt)) causes the a IRET to be emitted when an
IRETQ should be emitted. Below is my trivial do nothing main.c which I
compile with and then use objdump to view the assembler source.

I compiled x86_64-unknown-elf-xxxx using crosstool-ng, could that be a problem?

$ cat main.c
typedef unsigned long u64;

typedef struct intr_frame {
  u64 ip;
  u64 cs;
  u64 flags;
  u64 sp;
  u64 ss;
} intr_frame;

__attribute__ ((interrupt))
void ih(struct intr_frame* frame) {
}

void main(void) {
}

$ x86_64-unknown-elf-gcc -c main.c -o main.o -m64
$ x86_64-unknown-elf-objdump -d main.o

main.o:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <ih>:
   0: 55                   push   %rbp
   1: 48 89 e5             mov    %rsp,%rbp
   4: 50                   push   %rax
   5: 48 8d 45 08           lea    0x8(%rbp),%rax
   9: 48 89 45 f0           mov    %rax,-0x10(%rbp)
   d: 90                   nop
   e: 58                   pop    %rax
   f: 5d                   pop    %rbp
  10: cf                   iret

0000000000000011 <main>:
  11: 55                   push   %rbp
  12: 48 89 e5             mov    %rsp,%rbp
  15: 90                   nop
  16: 5d                   pop    %rbp
  17: c3                   retq