[Bug target/56564] movdqa on possibly-8-byte-aligned struct with -O3

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56564

--- Comment #18 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
(In reply to comment #17)
> Yeah, MachO is broken by design, guess the tests need to be restricted 
> to non-darwin non-PE.

Questions:
(1) What is PE?
(2) Is the second "return 0;" wrong code or valid optimization? If the former,
why?
(3) Is the decoration "__emutls_v." the same for all the emutls platforms? If
not, where can I find the variants?