Fix a register scavenger crash when dealing with undefined subregs.
The LowerSubregs pass needs to preserve implicit def operands attached to
EXTRACT_SUBREG instructions when it replaces those instructions with copies.

llvm-svn: 107189
2 files changed
tree: 06ec1a097f0cb5ebbe3510e8e80a0bc0bade92e8
  1. clang/
  2. compiler-rt/
  3. libcxx/
  4. lldb/
  5. llvm/