C# for-loop performance estimates: i++ vs. ++i implementation: which is faster? -

my question relates performance comparison (numeric estimates) pertinent following sample cases implementing for-loop in c# 4.0 and/or c# 5.0 in 4 different manners:

for (int i=0; i<10000; i++;){string _s="a";} (int i=0; i<10000; ++i;){string _s="a";} (int i=10000; i>0; i--;){string _s="a";} (int i=10000; i>; --i;){string _s="a";} 

question: of following implementations provide better performance (execution time) in generic for-loop implemented in c# 4.0 or c# 5.0?

note 1: string _s="a"; sample operation, potentially omitted testing purpose.

note 2: far, per discussion on (is there performance difference between i++ , ++i in c?) seems ++i runs faster i++ in c++.

the optimizer should know pre-incremented value of i never used, , therefore should same (simply increment i).

the reason i++ may slower ++i if compiler has save off old, pre-incremented value before incrementing i. however, given low register pressure, should trivial 1 additional "move" instruction.

if really care, suggest benchmark test cases. stopwatch provides enough functionality pretty estimation.

also, looking @ generated il show if there difference @ all.