Merging r283129:

Merging r283129:
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r283129 | hans | 2016-10-03 11:18:04 -0700 (Mon, 03 Oct 2016) | 6 lines

Jump threading: avoid trying to split edge into landingpad block (PR27840)

Splitting the edge is nontrivial because of the landing pad, and we would
currently assert trying to do it.

Differential Revision: https://reviews.llvm.org/D24680
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_39@286246 91177308-0d34-0410-b5e6-96231b3b80d8