direct calls to inttoptr constants

I'm compiling code which contains indirect function calls
via their absolute addresses, which are known/fixed at compile-time:

pseudo c code:
int main() {
int (* f)(int) = (int (*)(int))12345678;
return (*f)(0);
}

the IR looks like:
define i32 @main() nounwind {
entry:
%0 = tail call i32 inttoptr (i64 12345678 to i32 (i32)*)(i32 0) nounwind
ret i32 %0
}

on X86 llc 2.4 compiles this to:
.text
.align 16
.globl main
.type main,@function
main:
subl $4, %esp
movl $0, (%esp)
movl $12345678, %eax
call *%eax
addl $4, %esp
ret
.size main, .-main

.section .note.GNU-stack,"",@progbits

take a look at:
movl $12345678, %eax
call *%eax

does anyone know a way to cause llc to call the address directly?
hints where to start patching the codegen are also welcome.

expected assembly:
call *12345678

best regards
tobias

lib/Target/X86/X86InstrInfo.td, search for call and CALL. The problem is that the instruction only allows for 32-relative addresses. The form:

   call *0x20

isn't always valid as a 32-bit relative address. If you place that instruction at 1<<60, the destination is more than 1<<32 away.

If you want to say something about your model, say, all code is in the first 2bg, then, the instruction would be allowed. Problem is, I suspect there isn't enough model support for this, or your not using it.