simplify this code with the new m_Zero() pattern.  Make sure the select only has a single use, and generalize it to not require N to be a constant.
simplify this code with the new m_Zero() pattern.  Make sure the select only
has a single use, and generalize it to not require N to be a constant.



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@45250 91177308-0d34-0410-b5e6-96231b3b80d8

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