Merging r261039:
------------------------------------------------------------------------
r261039 | rnk | 2016-02-16 16:17:33 -0800 (Tue, 16 Feb 2016) | 6 lines
[X86] Fix a shrink-wrapping miscompile around __chkstk
__chkstk clobbers EAX. If EAX is live across the prologue, then we have
to take extra steps to save it. We already had code to do this if EAX
was a register parameter. This change adapts it to work when shrink
wrapping is used.
------------------------------------------------------------------------
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_38@261136
91177308-0d34-0410-b5e6-
96231b3b80d8