[llvm] [LLVM][TableGen] Use StringRef for various members `CGIOperandList::OperandInfo` (PR #140625)

[Craig Topper via llvm-commits]

================
@@ -142,8 +142,8 @@ bool CodeEmitterGen::addCodeToMergeInOperand(const Record *R,
   }
 
   std::pair<unsigned, unsigned> SO = CGI.Operands.getSubOperandNumber(OpIdx);
-  std::string &EncoderMethodName =
-      CGI.Operands[SO.first].EncoderMethodNames[SO.second];
+  const std::string EncoderMethodName =
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topperc wrote:

> It can, but then a simple string concat is now split over multiple lines. This will get better with my other PR (not yet uploaded) where this code:

Why would it be split over multiple lines?

```
raw_string_ostream OS(Case);

OS << " " << EncoderMethodName << "(MI, " << OpIdx;
```

https://github.com/llvm/llvm-project/pull/140625