Merging r261139:

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r261139 | deadalnix | 2016-02-17 11:21:28 -0800 (Wed, 17 Feb 2016) | 10 lines

Fix load alignement when unpacking aggregates structs

Summary: Store and loads unpacked by instcombine do not always have the
right alignement. This explicitely compute the alignement and set it.

Reviewers: dblaikie, majnemer, reames, hfinkel, joker.eph

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D17326

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llvm-svn: 271230