[PATCH] D29164: NVPTX: Refactor NVPTXInferAddressSpaces to check TTI

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In https://reviews.llvm.org/D29164#660049, @jlebar wrote:

> > I fixed the name of ADDRESS_SPACE_UNINITIALIZED to be UnknownAddressSpace in the cleanup commit which I think is more clear. I'd rather not deviate from the API/convention the other address space TTI functions already use (e.g. LSR defines the same constant and passes it to isLegalAddressingMode sometimes)
>
> The documentation as written doesn't ever say that we return -1 if the target doesn't have a flat AS.  In fact it's not even explicit whether all targets have a valid "flat" AS -- maybe we just return 0 for "normal" targets.


Then the pass will run and do something nonsensical. I think this would break people using addrspacecast for GC etc.


https://reviews.llvm.org/D29164