Fix some bugs found by running on llvm-test:
* MemCpyOptimization can only be optimized if the 3rd and 4th arguments are
  constants and we weren't checking for that.
* The result of llvm.memcpy (and llvm.memmove) is void* not sbyte*, put in
  a cast.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21570 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed