Merging r283612:

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r283612 | davide | 2016-10-07 14:53:09 -0700 (Fri, 07 Oct 2016) | 5 lines

[InstCombine] Don't unpack arrays that are too large (part 2).

This is similar to r283599, but for store instructions.
Thanks to David for pointing out!

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llvm-svn: 288070