@autorelease Pool and Loops (for, while, do) Syntax

@autorelease Pool and Loops (for, while, do) Syntax

clang allows the following loop syntax:
for (...) @autorelease { ... }
while (...) @autorelease { ... }
do @autorelease { ... } while (...);
I haven't found any documentation on that syntax so far (Apple doesn't use
this syntax in their guides, at least no in the guides introducing the
@autorelease construct), but is it reasonable to assume that the three
statement above are equivalent to the three statements below:
for (...) { @autorelease { ... } }
while (...) { @autorelease { ... } }
do { @autorelease { ... } } while (...);
Since that is what I would expect them to be (going by standard C syntax
rules), yet I'm not entirely sure if that's really the case. It could also
be some "special syntax", where the autorelease pool is not renewed for
every loop iteration.