Merging r372606:

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r372606 | spatel | 2019-09-23 06:30:23 -0700 (Mon, 23 Sep 2019) | 3 lines

[x86] fix assert with horizontal math + broadcast of vector (PR43402)

https://bugs.llvm.org/show_bug.cgi?id=43402
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llvm-svn: 374633