Revert "Use a stable-sort when combining bases"

This reverts commit 81417261a1.

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -15977,10 +15977,10 @@ static SDValue CombineBaseUpdate(SDNode *N,
   // Try to fold with other users. Non-constant updates are considered
   // first, and constant updates are sorted to not break a sequence of
   // strided accesses (if there is any).
-  std::stable_sort(BaseUpdates.begin(), BaseUpdates.end(),
-                   [](BaseUpdateUser &LHS, BaseUpdateUser &RHS) {
-                     return LHS.ConstInc < RHS.ConstInc;
-                   });
+  std::sort(BaseUpdates.begin(), BaseUpdates.end(),
+            [](BaseUpdateUser &LHS, BaseUpdateUser &RHS) {
+              return LHS.ConstInc < RHS.ConstInc;
+            });
   for (BaseUpdateUser &User : BaseUpdates) {
     if (TryCombineBaseUpdate(Target, User, /*SimpleConstIncOnly=*/false, DCI))
       return SDValue();