redesign the primary datastructure used by mem2reg to eliminate an
std::map of std::vector's (ouch!).  This speeds up mem2reg by 10% on 176.gcc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33974 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed