Merging r276361:

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r276361 | wolfgangp | 2016-07-21 16:28:18 -0700 (Thu, 21 Jul 2016) | 5 lines

Reverting r275115 which caused PR28634.
When empty (forwarding) basic blocks that are referenced by user labels
are removed, incorrect code may be generated.


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llvm-svn: 276656