[X86] Fix inconsistencies in different places where we split loads/stores.

-Use MinAlign instead of std::min.
-Use SelectionDAG::getMemBasePlusOffset.
-Apply offset to the pointer info for the second load/store created.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321536 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed