2.1.5. Avoid Broadcast Signals
Broadcast signals travel a large distance to reach individual registers. Because those fan-out registers may be spread out in the floorplan, use manual register duplication to improve placement. The correct placement of pipeline stages has a significant impact on performance.
In Sub-Optimal Pipelining of Broadcast Signals, the yellow box highlights registers inserted in a module to help with timing. The block broadcasts the output to several transceiver channels. These extra registers may not improve timing sufficiently because the final register stage fans out to destinations over a wide area of the device.
In addition to duplicating the last pipeline register, you can apply the dont_merge synthesis attribute to avoid merging of the duplicate registers during synthesis, which eliminates any benefit.
The Compiler automatically adds pipeline stages and moves registers into Hyper-Registers, whenever possible. You can also use manual pipelining to drive even better placement result.
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