Merging r195493:

Merging r195493:
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r195493 | arsenm | 2013-11-22 11:24:39 -0800 (Fri, 22 Nov 2013) | 6 lines

StructurizeCFG: Fix verification failure with some loops.

If the beginning of the loop was also the entry block
of the function, branches were inserted to the entry block
which isn't allowed. If this occurs, create a new dummy
function entry block that branches to the start of the loop.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@195606 91177308-0d34-0410-b5e6-96231b3b80d8