[llvm] [RISCV] Use decodeUImmLog2XLenNonZeroOperand in decodeRVCInstrRdRs1UImm. NFC (PR #133759)

[Craig Topper via llvm-commits]

================
@@ -661,7 +661,7 @@ def C_SLLI_HINT : RVInst16CI<0b000, 0b10, (outs GPRX0:$rd_wb),
                   Sched<[WriteShiftImm, ReadShiftImm]> {
   let Constraints = "$rd = $rd_wb";
   let Inst{11-7} = 0;
-  let DecoderMethod = "decodeRVCInstrRdRs1UImm";
+  let DecoderMethod = "decodeRVCInstrRdRs1UImmLog2XLenNonZero";
----------------
topperc wrote:

The instruction definition I'm changing is

```
def C_SLLI_HINT : RVInst16CI<0b000, 0b10, (outs GPRX0:$rd_wb),                   
                             (ins GPRX0:$rd, uimmlog2xlennonzero:$imm),          
                             "c.slli", "$rd, $imm">,                             
                  Sched<[WriteShiftImm, ReadShiftImm]> {                         
  let Constraints = "$rd = $rd_wb";                                              
  let Inst{11-7} = 0;                                                            
  let DecoderMethod = "decodeRVCInstrRdRs1UImm";                                 
} 
```

which doesn't allow immediate of 0 in the parser due to uimmlog2xlennonzero.

I think the hint with imm==0 is c.slli64

```
def C_SLLI64_HINT : RVInst16CI<0b000, 0b10, (outs GPR:$rd_wb), (ins GPR:$rd),    
                               "c.slli64", "$rd">,                               
                    Sched<[WriteShiftImm, ReadShiftImm]> {                       
  let Constraints = "$rd = $rd_wb";                                              
  let imm = 0;                                                                   
} 
```

https://github.com/llvm/llvm-project/pull/133759