Fix two problems:

Fix two problems:
  * Load Implementation can cause unaligned memory accesses, which caused
    problems for sparc.
  * cast from pointer to pointer would zero the upper 32 bits of the pointer
    which obviously causes problems on 64 bit hosts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4454 91177308-0d34-0410-b5e6-96231b3b80d8