[llvm] [NFC][LLVM] Refactor MachineInstr operand accessors (PR #137261)

[Rahul Joshi via llvm-commits]

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@@ -676,68 +672,61 @@ class MachineInstr
   const_mop_iterator operands_begin() const { return Operands; }
   const_mop_iterator operands_end() const { return Operands + NumOperands; }
 
-  iterator_range<mop_iterator> operands() {
-    return make_range(operands_begin(), operands_end());
+  MutableArrayRef<MachineOperand> operands() {
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jurahul wrote:

Thanks. I see your point. `iterator_range<>` does not have a `[]` operator, so it's not possible for clients to use direct indexing, but with `ArrarRef` they can. My slight pushback is that `mop_iterator` itself is a pointer, so nothing prevents someone to do `operands_begin()[i]` today as well, so in that sense the sequential nature of the store is still exposed through that API, just that with `ArrayRef` it will be exposed at more places. May be a compromise is to use `ArrayRef` internally in the impl of these functions (which is really what I was after). Let me give that a stab and we can see if its worth it.

https://github.com/llvm/llvm-project/pull/137261