[Bug target/56560] [4.6/4.7 regression] vzeroupper clobbers argument with AVX

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56560

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> 2013-03-11 19:34:29 UTC ---
Created attachment 29645
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29645
A patch

This patch adds expand_args to track library calls to
expend arguments.  We add vzeroupper when expand_args == 1,
which indicates we are expanding the actual function.