Adding some trailing whitespace after a comment previously ending with \ to ensure that it isn't lexed as a multiline comment. This silences some -Wcomment warnings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211950 91177308-0d34-0410-b5e6-96231b3b80d8
[NVPTX] Use GreatestCommonDivisor64 from MathExtras instead of using our own.  Thanks Hal!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211952 91177308-0d34-0410-b5e6-96231b3b80d8