[llvm] [ConstantFold][RFC] Refactor getBinOpAbsorber function (PR #109736)

[Nikita Popov via llvm-commits]

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@@ -1210,8 +1210,11 @@ class ConstantExpr : public Constant {
   /// Return the absorbing element for the given binary
   /// operation, i.e. a constant C such that X op C = C and C op X = C for
   /// every X.  For example, this returns zero for integer multiplication.
-  /// It returns null if the operator doesn't have an absorbing element.
-  static Constant *getBinOpAbsorber(unsigned Opcode, Type *Ty);
+  /// If AllowLHSConstant is true, operand 1 is a constant C that must be
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nikic wrote:

```suggestion
  /// If AllowLHSConstant is true, the LHS operand is a constant C that must be
```
It's not clear what "operand 1" means here (because we often use operands 0 and 1 rather than 1 and 2).

https://github.com/llvm/llvm-project/pull/109736