[llvm] [RISCV] Add PseudoClearGPR to the special cases in RISCVInstrInfo::getInstSizeInBytes. (PR #203637)

[Craig Topper via llvm-commits]

topperc wrote:

> I failed to look at the original PR, but why do we have Size = 8 by default? Isn't it just a single ADDI expansion?
> 
> ```
> let hasSideEffects = 0, mayLoad = 0, mayStore = 0, Size = 8,
>     isCodeGenOnly = true in
> def PseudoClearGPR : Pseudo<(outs GPR:$rd), (ins), []>,
>                      PseudoInstExpansion<(ADDI GPR:$rd, X0, 0)>;
> ```

That should be 4. I'll fix that too.

https://github.com/llvm/llvm-project/pull/203637