In Vivado 2014.4, the source files for an IP have been changed.
For example, for AXI Interconnect, the file "axi_interconnect/fifo_generator_v12_0/simulation/fifo_generator_vlog_beh.v" existed in previous versions but not in 2014.4.
Why was this change made?
Starting in Vivado 2014.4, all source files for a particular encrypted IP are concatenated together into a single file.
This reduces the total number of inaccessible files in design views and in the file system.
This change might require manually-created build scripts to be updated to reflect new file names even if the IP itself has not changed.