Merging r323759:

Merging r323759:
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r323759 | spatel | 2018-01-30 14:53:59 +0100 (Tue, 30 Jan 2018) | 10 lines

[DSE] make sure memory is not modified before partial store merging (PR36129)

We missed a critical check in D30703. We must make sure that no intermediate
store is sitting between the stores that we want to merge.

This should fix:
https://bugs.llvm.org/show_bug.cgi?id=36129

Differential Revision: https://reviews.llvm.org/D42663

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@324086 91177308-0d34-0410-b5e6-96231b3b80d8