Instead of copying arguments from the source function to the
destination, steal them. This has a few advantages.
- The ValueMap doesn't need to be seeded with (or cleared of)
Arguments.
- Often the destination function won't have created any arguments yet,
so this avoids malloc traffic.
- Argument names don't need to be copied.
Because argument lists are lazy, this required a new
Function::stealArgumentListFrom helper.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265519 91177308-0d34-0410-b5e6-96231b3b80d8
