Merging r199832:

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r199832 | rafael.espindola | 2014-01-22 15:20:52 -0500 (Wed, 22 Jan 2014) | 11 lines

Fix pr18515.

My understanding (from reading just the llvm code) is that
* most ppc cpus have a "sync n" instruction and an msync alias that is
* "sync 0".
* "book e" cpus instead have a msync instruction and not the more
general "sync n"

This patch reflects that in the .td files, allowing a single codepath
for
asm ond obj streamer and incidentelly fixes a crash when EmitRawText was
called on a obj streamer.

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llvm-svn: 205820