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llvm / circt

Circuit IR Compilers and Tools
https://circt.org
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[FIRRTL] Feature Request: Please support options for omission of the randomization code #4202

Closed mwachs5 closed 2 years ago

mwachs5 commented 2 years ago

Scala FIRRTL Compiler supported annotations to control the emission of randomization code at the top of the file, which can be quite noisy. In particular the CustomDefaultRegisterEmission.disableRandomization flag and case "disableMemRandomization" => CustomDefaultMemoryEmission(MemoryNoInit) was useful when trying to emit instructive examples and documentation where the initialization code is huge and not exactly educational.

See https://github.com/chipsalliance/firrtl/blob/b027eb466b033a0a9d229f19feb931ddb292a9fa/src/main/scala/firrtl/EmissionOption.scala#L15

other discussion here: https://discourse.llvm.org/t/how-to-disable-randomize-in-firtool-generated-sv/65990

seldridge commented 2 years ago

Thanks for filing a ticket about this.

I'd modify this slightly to say that we should add an option to control randomization to firtool, e.g., -disable-register-randomization. We can bridge the upstream annotation in chisel-circt to map to this.