1. A computer accessible memory medium that stores program instructions executable by a processor to: display a graphical data flow program in response to user input, wherein the graphical data flow program comprises a plurality of interconnected nodes that visually indicate functionality of the graphical data flow program, wherein the graphical data flow program comprises a graphical indicator that specifies to a compiler that the compiler is to attempt to automatically generate data flow program code that parallelizes a specified portion of the graphical data flow program for concurrent execution; and automatically generate the program code implementing a plurality of second data flow program portions based on the graphical indicator, wherein each of the second data flow program portions is configured to execute a respective one or more iterations; wherein during execution of the graphical data flow program, the plurality of second data flow program portions are configured to execute at least a portion of iterations concurrently; and wherein execution of the plurality of second data flow program portions is functionally equivalent to sequential execution of the iterations of the first graphical data flow program portion.