Merging r201507:

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r201507 | craig.topper | 2014-02-17 05:03:43 -0500 (Mon, 17 Feb 2014) | 2 lines

Fix diassembler handling of rex.b when mod=00/01/10 and bbb=101. Mod=00 should ignore the base register entirely. Mod=01/10 should treat this as R13 plus displacment. Fixes PR18860.

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llvm-svn: 206056