// foo.d :

int main() {
  volatile int* foo = cast(int*)0x1234;
  *foo = 5;
  return 0;
}

/*

compile with
$ ldc -ofoo foo.d -mattr=-sse

gives:

copying RDX to ESI <-- I added this to llvm... it is doing a 64bit to 32bit register copy
Cannot emit physreg copy instruction
UNREACHABLE executed at /home/wilkie/build/llvm/lib/Target/X86/X86InstrInfo.cpp:2014!
0  ldc             0x0000000000f2beaf
1  ldc             0x0000000000f2c9ea
2  libpthread.so.0 0x00007fb193e861c0
3  libc.so.6       0x00007fb192f90595 gsignal + 53
4  libc.so.6       0x00007fb192f91a16 abort + 390
5  ldc             0x0000000000f178c4 llvm::llvm_unreachable_internal(char const*, char const*, unsigned int) + 356
6  ldc             0x000000000076a337 llvm::X86InstrInfo::copyPhysReg(llvm::MachineBasicBlock&, llvm::ilist_iterator<llvm::MachineInstr>, llvm::DebugLoc, unsigned int, unsigned int, bool) const + 2263
7  ldc             0x000000000095f650
8  ldc             0x0000000000eb9c17 llvm::FPPassManager::runOnFunction(llvm::Function&) + 599
9  ldc             0x0000000000eb9dbb llvm::FunctionPassManagerImpl::run(llvm::Function&) + 155
10 ldc             0x0000000000eb9f4c llvm::FunctionPassManager::run(llvm::Function&) + 108
11 ldc             0x0000000000657561 write_asm_to_file(llvm::TargetMachine&, llvm::Module&, llvm::raw_fd_ostream&) + 577
12 ldc             0x000000000065c008 writeModule(llvm::Module*, std::string) + 552
13 ldc             0x00000000006a07c6 main + 6950
14 libc.so.6       0x00007fb192f7cc4d __libc_start_main + 253
15 ldc             0x0000000000586a79
Stack dump:
0.      Running pass 'Subregister lowering instruction pass' on function '@_Dmain'
Aborted

*/