@autoreleasepool without ARC?

From http://clang.llvm.org/docs/AutomaticReferenceCounting.html#autoreleasepool:

@autoreleasepool may be used in non-ARC translation units, with equivalent semantics.

and Greg Parker says [1] [2]:

LLVM 3.0’s @autoreleasepool { ... } is much faster than NSAutoreleasePool if your deployment target is new enough. No ARC required. (…) always works, but it’s faster with deployment target of OS X 10.7 or iOS 5.0.

So you may use @autoreleasepool regardless of ARC, and it’ll be faster than NSAutoreleasePool on OS X v10.7+ and iOS 5.0+.