swift234

implement support for conditional destruction of tuple elements.

a testcase like this:

func test(cond : Bool) {
  var x : (SomeClass, SomeClass)

  if cond {
    x.0 = getSomeClass()
  } else {
    x.1 = getSomeClass() 
  }
}

now ends up with an epilog to destroy "x" that looks like this:

  %1 = builtin_function_ref "lshr_Int2" : $@thin @callee_owned (Builtin.Int2, Builtin.Int2) -> Builtin.Int2 // user: %37
  %2 = builtin_function_ref "trunc_Int2_Int1" : $@thin @callee_owned (Builtin.Int2) -> Builtin.Int1 // users: %38, %31
...
  %30 = load %4#1 : $*Builtin.Int2                // users: %37, %31
  %31 = apply %2(%30) : $@thin @callee_owned (Builtin.Int2) -> Builtin.Int1 // user: %32
  cond_br %31, bb4, bb5                           // id: %32

bb4:                                              // Preds: bb3
  %33 = tuple_element_addr %7#1 : $*(SomeClass, SomeClass), 0 // user: %34
  destroy_addr %33 : $*SomeClass                  // id: %34
  br bb5                                          // id: %35

bb5:                                              // Preds: bb3 bb4
  %36 = integer_literal $Builtin.Int2, 1          // user: %37
  %37 = apply %1(%30, %36) : $@thin @callee_owned (Builtin.Int2, Builtin.Int2) -> Builtin.Int2 // user: %38
  %38 = apply %2(%37) : $@thin @callee_owned (Builtin.Int2) -> Builtin.Int1 // user: %39
  cond_br %38, bb6, bb7                           // id: %39

bb6:                                              // Preds: bb5
  %40 = tuple_element_addr %7#1 : $*(SomeClass, SomeClass), 1 // user: %41
  destroy_addr %40 : $*SomeClass                  // id: %41
  br bb7                                          // id: %42

bb7:                                              // Preds: bb5 bb6
  dealloc_stack %7#0 : $*@local_storage (SomeClass, SomeClass) // id: %43





Swift SVN r10701