[llvm] [X86] Add MI-layer routine for getting the index of the first address operand (PR #78019)

[Phoebe Wang via llvm-commits]

================
@@ -289,10 +289,8 @@ static unsigned getYMMtoXMMStoreOpcode(unsigned StoreOpcode) {
 }
 
 static int getAddrOffset(const MachineInstr *MI) {
-  const MCInstrDesc &Descl = MI->getDesc();
-  int AddrOffset = X86II::getMemoryOperandNo(Descl.TSFlags);
+  const int AddrOffset = X86::getFirstAddrOperandIdx(*MI);
----------------
phoebewang wrote:

The `const` doesn't work here. Change the function to `static const int` or remove it.

https://github.com/llvm/llvm-project/pull/78019