[PATCH] D65649: [RISCV] Add MC encodings and tests of the Bit Manipulation extension

[Paolo Savini via Phabricator via llvm-commits]

PaoloS marked 2 inline comments as done.
PaoloS added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVInstrInfoB.td:67
+
+class RVBInstR4Reg<bits<2> funct2, bits<3> funct3, RISCVOpcode opcode,
+                   string opcodestr, string argstr>
----------------
lewis-revill wrote:
> Is there an explanation for why this instruction is not re-using `RVInstR4` from `RISCVInstrFormats.td`?
Yes, that was because with RVInstR4 I couldn't use funct3 for encoding. As it is declared in `RISCVInstrFormats.td`:

```
class RVInstR4<bits<2> funct2, RISCVOpcode opcode, dag outs, dag ins,
               string opcodestr, string argstr>
    : RVInst<outs, ins, opcodestr, argstr, [], InstFormatR4> {
  bits<5> rs3;
  bits<5> rs2;
  bits<5> rs1;
  bits<3> funct3;
  bits<5> rd;

  let Inst{31-27} = rs3;
  let Inst{26-25} = funct2;
  let Inst{24-20} = rs2;
  let Inst{19-15} = rs1;
  let Inst{14-12} = funct3;
  let Inst{11-7} = rd;
  let Opcode = opcode.Value;
}
```
any parameter passed as funct3 would be ignored.
I opted for a new class that allows to use funct3 as an extra opcode field too. It would be good to consider that for the original RVInstR4 too though.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65649/new/

https://reviews.llvm.org/D65649