[PATCH] D39386: [Power9] Allow gpr callee saved spills in prologue to vector registers rather than stack

[Zaara Syeda via Phabricator via llvm-commits]

syzaara added a comment.

In https://reviews.llvm.org/D39386#910018, @hfinkel wrote:

> This is pretty neat.
>
> Is the CFI limitation temporary? I imagine that you can use MCCFIInstruction::createRegister to indicate that the value that used to be in the GPR is now in the vector register?
>
> Will be also be able to use this same infrastructure in order to save callee-saved condition registers to otherwise available GPRs (instead of to the stack)?


The CFI limitation is temporary. I did notice the createRegister, but I don't think there is support in the debuggers/unwinders for moving from a vector register to a GPR. Once we know how to handle this, we can remove the CFI limitation. The same infrastructure can be used for other available GPRs and I think createRegister should be able to handle that.


https://reviews.llvm.org/D39386