will get its preferred alignment. It has to be careful and cautiously assume
it will just get the ABI alignment. This prevents instcombine from rounding
up the alignment of a load/store without adjusting the alignment of the alloca.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61934 91177308-0d34-0410-b5e6-96231b3b80d8