[PATCH] D23367: [SystemZ] Use valid base/index registers for memory constraints

[Ulrich Weigand via llvm-commits]

uweigand added a comment.

Hmm, I guess that makes sense.  I'm wondering why most other targets don't have to do anything similar ...

I am a bit concerned about the ISD::Register tests.  I assume this is to catch the case where no base and/or no index register are actually used; in those cases selectBDXAddr sets Base and/or Index to CurDAG->getRegister(0, VT).  In those cases, leaving this as-is is fine.  (Mentioning this in a comment would be good, though.)  However, can there be other instances of ISD::Register?  Can this e.g. be hard-coded by a user somehow?  What if there is a hard-coded register, which is *not* suitable for use in addressing?


https://reviews.llvm.org/D23367