[mono][interp] Reduce redundant moves with calls

src/mono/mono/mini/interp/transform.c

@@ -9187,11 +9187,6 @@ interp_cprop (TransformData *td)
 					}
 				} else {
 					cprop_sreg (td, ins, &sregs [i], local_defs);
-					// This var is used as a source to a normal instruction. In case this var will
-					// also be used as source to a call, make sure the offset allocator will create
-					// a new temporary call arg var and not use this one. Call arg vars have special
-					// semantics. They can be assigned only once and they die once the call is made.
-					td->locals [sregs [i]].flags |= INTERP_LOCAL_FLAG_NO_CALL_ARGS;
 				}
 			}
 
@@ -10395,9 +10390,12 @@ interp_alloc_offsets (TransformData *td)
 
 					while (var != -1) {
 						if (td->locals [var].flags & INTERP_LOCAL_FLAG_GLOBAL ||
+								!td->local_ref_count || td->local_ref_count [var] > 1 ||
 								td->locals [var].flags & INTERP_LOCAL_FLAG_NO_CALL_ARGS) {
-							// A global var is an argument to a call, which is not allowed. We need
-							// to copy the global var into a local var
+							// Some vars can't be allocated on the call args stack, since the constraint is that
+							// call args vars die after the call. This isn't necessarily true for global vars or
+							// vars that are used by other instructions aside from the call.
+							// We need to copy the var into a new tmp var
 							int new_var = create_interp_local (td, td->locals [var].type);
 							td->locals [new_var].call = ins;
 							td->locals [new_var].flags |= INTERP_LOCAL_FLAG_CALL_ARGS;