7.3. Merge Memories to Reduce Area
In some cases, you can save FPGA memory blocks by merging your component memories so that they consume fewer memory blocks, reducing the FPGA area your component uses. Use the hls_merge attribute to force the Intel® HLS Compiler Pro Edition to implement different variables in the same memory system.
When you merge memories, multiple component variables share the same memory block. You can merge memories by width (width-wise merge) or depth (depth-wise merge). You can merge memories where the data in the memories have different datatypes.
The following diagram shows how four memories can be merged width-wise and depth-wise.