Add more functions to the target library information.

In the process of migrating optimizations from the simplify-libcalls pass
to the instcombine pass I noticed that a few functions are missing from
the target library information.  These functions need to be available for
querying in the instcombine library call simplifiers.  More functions will
probably be added in the future as more simplifiers are migrated to
instcombine.

llvm-svn: 167659