[Loads] Fix crash in is isDereferenceableAndAlignedPointer()

Summary:
We were trying to add APInt values with different bit sizes after
visiting an addrspacecast instruction which changed the bit width
of the pointer.

Reviewers: majnemer, hfinkel

Subscribers: hfinkel, wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D24774

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285407 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed