Hex-Rays and negative structure offsets

[Avalon]

Well Ida has analyzed and defined in the stack setup:

int *v1; // edi
_DWORD *v2; // esi
_DWORD *v3; // eax

If you create a struct of 3 PDWORD's, and apply it on the stack at v1 i.e.

struct SomeStruct
{
    PDWORD pdwField1, 
    PDWORD pdwField2, 
    PDWORD pdwField3
}

Then Ida will remove that *v2 and *v3, and they will become struct members on the stack of SomeStruct.pdwField2 and SomeStruct.pdwField3 which you can define as any pointer type you want, with the struct you defined.