> It could be, but after having looked briefly at the size of the design for
> RISC-V Rocket and especially BOOM I wonder if it's all overly complicated.
> They even built their own high level hardware language (Chisel) that
> generates Verilog using Scala. Yuck.

It's possible to build a simple and perfectly usable RISC-V processor
on an FPGA in verilog.  The one I use is
https://github.com/cliffordwolf/picorv32 , written by Clifford Wolf.
Its small size means it can be (and has been) formally verified, and
(for some applications at least) you can compensate for the modest
performance by putting lots of them on one chip.

> Also, there's appears to be quite alot of compiler optimizations in gcc for
> RISC-based chips.

Again, it's possible to build a simple and perfectly usable C compiler
for RISC-V without going overboard with optimisation.  I've been
working on re-targeting the Plan 9 C toolchain for RISC-V.  It's at
the stage where it can successfully compile itself, but floating point
support is not yet complete.  If anyone is interested, let me know.