Optimization compiler means that the compiler tries to minimize the execution time, memory usages, and code length and power requirement. But within that parameter the execution time is the most important parameter whereas the memory usage is almost negligible nowadays. After the popularity of portable computer systems like laptops, palmtops, Tablets etc. another major optimization parameter has become the power consumption. That means using minimum numbers of resources how the program can be successfully executed without alteration of the final outcome. Peephole optimization is widely used optimization technique still yet in the field of compiler optimization. It is the technique based on string pattern matching using regular expression and replacing a piece of code with the equivalent piece of code which is shorter and faster than the original one. However the efficiency of a compiler depends on the machine architecture, target application and compilation environment. So optimization technique is to get a way which could balance all those parameters. Nowadays excluding the peephole optimization technique there are lot of other which is dedicated to get a balanced strategy among those parameters. So in this paper we have discussed about those methods with their pros and cons. As far in this field no technique is perfect for all situations, different strategies are healthy for different situations. We have also discussed those situations where a strategy, depending on parameter can give us a better result compare to others and also cannot be a good for any other parameters. In this paper we have also proposed a new technique of parallel execution in multicore system. Basically the technique depends on the dependencies of instruction on each other and according to those dependencies we have segmented the code, so that they can be executed parallel without affecting the final outcome. The details is in our proposed algorithm section. © 2016, International Journal of Pharmacy and Technology. All rights reserved.