[PATCH] D11319: Pass subtarget feature "+reserve-r9" instead of passing backend option "-arm-reserve-r9"

[Akira Hatanaka]

ahatanak added a comment.

In http://reviews.llvm.org/D11319#208367, @echristo wrote:

> Question:
>
> Would it be better to just use reserve=NUM and parse that rather than the single +/- per register? Or is it just not worth it here?


I guess it could be useful for debugging or testing code-gen passes (for example, register allocator).

AArch64 has a similar option "aarch64-reserve-x18". Are there other targets or use cases that require reserving registers?


http://reviews.llvm.org/D11319