Atomic loads on x86

gistfile1.txt

$ cat -n atomic.cc 
     1  #include <atomic>
     2  
     3  int func(std::atomic<int> *x)
     4  {
     5      return std::atomic_load(x);
     6  }

$ g++ -O2 -std=c++0x -S -o - atomic.cc 
        .file   "atomic.cc"
        .text
        .p2align 4,,15
        .globl  _Z4funcPSt6atomicIiE
        .type   _Z4funcPSt6atomicIiE, @function
_Z4funcPSt6atomicIiE:
.LFB382:
        .cfi_startproc
        mfence
        movl    (%rdi), %eax
        mfence
        ret
        .cfi_endproc
.LFE382:
        .size   _Z4funcPSt6atomicIiE, .-_Z4funcPSt6atomicIiE
        .ident  "GCC: (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3"
        .section        .note.GNU-stack,"",@progbits