A tracing just-in-time (TJIT) compiler system is described for performing parallelization of code in a runtime phase in the execution of code. Upon detecting a hot loop during the execution of the code, the compiler system extracts trace information from sequentially recorded traces. In a first phase, the compiler system uses the trace information to identify at least one group of operation components that can be operated on in a parallel manner. In a second phase, the compiler system provides instructions which allocate the group of operation components to plural processing resources. A native code generator module carries out those instructions by recompiling native code that directs the operation of a native system to perform parallel processing. The compiler system terminates a group if it encounters program data in a loop iteration that is not consistent with previously encountered predicated information (upon which it records a new trace in a sequential manner).