It gets its own implementation totally divorced from the (presumably
performance-sensitive) routines which parse into a uint64_t.
Add APInt::operator|=(uint64_t), which is situationally much better than
using a full APInt.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97381 91177308-0d34-0410-b5e6-96231b3b80d8