Merging r316035:

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r316035 | tnorthover | 2017-10-17 14:43:52 -0700 (Tue, 17 Oct 2017) | 6 lines

AArch64: account for possible frame index operand in compares.

If the address of a local is used in a comparison, AArch64 can fold the
address-calculation into the comparison via "adds". Unfortunately, a couple of
places (both hit in this one test) are not ready to deal with that yet and just
assume the first source operand is a register.
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llvm-svn: 319231