llvm / llvm/circt

[ExportVerilog] Invalid verilog caused by i0 value used by fwrite

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Description

```mlir
hw.module @Foo(%fd: i32, %v: i0) {
sv.initial {
sv.fwrite %fd, "%d"(%v) : i0
}
hw.output
}
```

The current output is:
```verilog
module Foo( // neko.mlir:1:1
input [31:0] fd
// input /*Zero Width*/ v
);

initial // neko.mlir:2:1
$fwrite(fd, "%d", v); // neko.mlir:3:9
endmodule
```

fwrite shouldn't have i0 value operands.

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Research direction

Reproduce the provided MLIR module with the ExportVerilog path and inspect how sv.fwrite handles its i0 value operand. Done means the input no longer produces invalid Verilog containing the zero-width v operand, with coverage for this case.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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