Merging r258611:
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r258611 | majnemer | 2016-01-22 21:41:29 -0800 (Fri, 22 Jan 2016) | 6 lines
[PruneEH] FuncletPads must not have undef operands
Instead of RAUW with undef, replace the first non-token instruction with
unreachable.
This fixes PR26263.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_38@261131
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