[RFC] combining memories for byte enables #3157
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The RAMs inferred by GHDL are split into separate instances for byte enables. This pass recombines memories that have the same input address (and matching characteristics) allowing a single BRAM to be used with byte enables. Work in progress, needs more checks for memory compatibility Briefly tested to work for microwatt
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Currently the RAMs inferred by GHDL are split into separate instances for byte enables. This leads to more cells being used, so I've tried this optimisation pass to combine the separate memories if they share the same input source.
Would that approach be worth pursuing? The patch currently works sufficiently to reduce resources used by Microwatt though I'd need to add better checking that memories being combined are compatible.
Or should the byte enable inference instead be done GHDL? Adding @tgingold for any thoughts.
A test example is https://gist.github.com/mkj/00f8d39c95ec9e173b3534b686a7ad2a