This patch adds support for inline assembly address operands using the "p"
constraint on X86 and SystemZ.
This was in fact broken on X86 (see example at
https://reviews.llvm.org/D110267, Nov 23).
These operands should probably be treated the same as memory operands by
CodeGenPrepare, which have been commented with "TODO" there.
Review: Xiang Zhang and Ulrich Weigand
Differential Revision: https://reviews.llvm.org/D122220