Merging r309614:

Merging r309614:
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r309614 | kbelochapka | 2017-07-31 13:11:49 -0700 (Mon, 31 Jul 2017) | 7 lines

[X86][MMX] Added custom lowering action for MMX SELECT (PR30418)
Fix for pr30418 - error in backend: Cannot select: t17: x86mmx = select_cc t2, Constant:i64<0>, t7, t8, seteq:ch
Differential Revision: https://reviews.llvm.org/D34661

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_50@310673 91177308-0d34-0410-b5e6-96231b3b80d8