Symbolic execution is an important and popular technique used in several software engineering tools for test case generation, debugging and program analysis. As such improving the performance of symbolic execution can have huge impact on the effectiveness of such tools. In this paper, we present a technique to systematically introduce undefined behaviors during compilation to speed up the subsequent symbolic execution of the program. We have implemented our technique inside LLVM and tested with an existing symbolic execution engine (Pathgrind). Preliminary results on the SIR repository benchmark are encouraging and show 48% speed up in time and 30% reduction in the number of constraints.