Merging r295215:
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    r295215 | arnolds | 2017-02-15 10:57:06 -0800 (Wed, 15 Feb 2017) | 11 lines
    
    ThreadSanitizer: don't track swifterror memory addresses
    
    They are register promoted by ISel and so it makes no sense to treat them as
    memory.
    
    Inserting calls to the thread sanitizer would also generate invalid IR.
    
    You would hit:
    
    "swifterror value can only be loaded and stored from, or as a swifterror
    argument!"
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    llvm-svn: 295376