This could affect performance slightly in real-world code if virtual functions are used to return constants in some overrides.

test.d:

int main() {
   return 0;
}

dmd -c -O -inline -release test.d

Disassembly of _Dmain in test.o:

_Dmain  PROC
        push    rbp                                     ; 0000 _ 55
        mov     rbp, rsp                                ; 0001 _ 48: 8B. EC
        xor     eax, eax                                ; 0004 _ 31. C0
        pop     rbp                                     ; 0006 _ 5D
        ret                                             ; 0007 _ C3
_Dmain  ENDP

Do we really need to do the push rbp; mov rbp, rsp; pop rbp when the function doesn't actually use any stack and just sets eax to zero and returns?  GDC elides these extra instructions.  In GDC, compiled with -O1 or higher, _Dmain's body is:

_Dmain  PROC
        xor     eax, eax                                ; 0000 _ 31. C0
        ret                                             ; 0002 _ C3
_Dmain  ENDP