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

[Rahul Joshi via llvm-commits]

================
@@ -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() {
----------------
jurahul wrote:

I am not sure. It only makes it impossible if someone assumes that the return type of operands() is an ArrayRef, with code like:

ArrayRef<MCOperand> ops = MI.operands().

And that's true with today's iterator<mop_iterator> as well. Even today, we cannot change the storage to a segregated arrays without changing the return type of operands(). My claim is that this is ok for well behaving clients and it's not exposing the details any more than iterator<mop_iterator>.

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