they are lowered to instruction sequences more complex than a simple
load, such that CodeGen cannot rematerialize them, a reload from a
spill slot is likely to be cheaper than the complex sequence.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89374 91177308-0d34-0410-b5e6-96231b3b80d8
