Update patch for the pad short functions pass for Intel Atom (only).

Adds a check for -Oz, changes the code to not re-visit BBs,
and skips over DBG_VALUE instrs.

Patch by Andy Zhang.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172258 91177308-0d34-0410-b5e6-96231b3b80d8