[Bug middle-end/53623] [4.7/4.8 Regression] sign extension is effectively split into two x86-64 instructions

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53623

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to H.J. Lu from comment #12)
> This regression is only fixed in 4.9 and should be backported to 4.8
> branch.

Unfortunately, r206418 introduced many regressions.  Backport r206418
requires backporting all bug fixes caused by r206418.