Xilinx, Inc.
Data flow graph optimization techniques for RTL loops with conditional-exit statements

Abstract:

A computer-implemented method includes compiling a Register Transfer Level (RTL) code to form a data flow graph (DFG). The computer-implemented method includes identifying a chain of multiplexers in the DFG, wherein the chain of multiplexers includes exit multiplexers associated with a loop exit path and non-exit multiplexers. The computer-implemented method also includes traversing a topological order of the DFG in reverse. The computer-implemented method also includes computing fanin-cones for each two consecutive exit multiplexers. The computer-implemented method includes generating a truth table responsive to valid fanin-cones and back propagating select conditions for the each two consecutive exit multiplexers. The computer-implemented method includes eliminating an exit multiplexer from the each two consecutive exit multiplexers based on the truth table. The computer-implemented method further includes transforming the DFG to a new DFG based on the truth table.