Merge commit 5bbb604bb from llvm git (by Craig Topper):

[InstCombine] Disable some portions of foldGEPICmp for GEPs that
return a vector of pointers. Fix other portions.

llvm-svn: 370114

This should fix instances of 'Assertion failed: (isa<X>(Val) &&
"cast<Ty>() argument of incompatible type!"), function cast, file
/usr/src/contrib/llvm/include/llvm/Support/Casting.h, line 255', when
building openjdk8 for aarch64 and armv7.

Reported by: jbeich
PR: 236566
MFC after: 3 days