Question

I have seen that C# “is optimized” for accessing 1D array (does not call a function to access element), but for multidim-arrays function GetValue is called each time. Why not instead of calling this function each time “normal” access (pointers shifting + checking) is not implemented or at least this function is not flattened ?

I can not find the logical reason.
(performance for multidim-arrays are not great)

Answer 1

I didn’t uncheck “Supress JIT optimization…” therefore function call GetValue wasn’t inlined.

Optimized code:

b = a[3, 5];
00000026  mov         eax,3 
0000002b  lea         edx,[eax+2] 
0000002e  sub         eax,dword ptr [ecx+10h] 
00000031  cmp         eax,dword ptr [ecx+8] 
00000034  jae         0000010B 
0000003a  sub         edx,dword ptr [ecx+14h] 
0000003d  cmp         edx,dword ptr [ecx+0Ch] 
00000040  jae         0000010B 
00000046  imul        eax,dword ptr [ecx+0Ch] 
0000004a  add         eax,edx 
0000004c  mov         edi,dword ptr [ecx+eax*4+18h]