[Hexagon] Handle non-aligned offsets in globals in extender optimization
Instructions like memd(r0+##global+1) are legal as long as the entire
address is properly aligned. Assuming that "global" is aligned at an
8-byte boundary, the expression "global+1" appears to be misaligned.
Handle such cases in HexagonConstExtenders, and make sure that any non-
extended offsets generated are still aligned accordingly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323799
91177308-0d34-0410-b5e6-
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