[PATCH] D75098: Add TCOPY, a terminator form of the COPY instr

[Bill Wendling via Phabricator via llvm-commits]

void added a comment.

In D75098#2026425 <https://reviews.llvm.org/D75098#2026425>, @void wrote:

> In D75098#2021573 <https://reviews.llvm.org/D75098#2021573>, @qcolombet wrote:
>
> > Thanks Bill for the detailed explanations. A couple more questions.
> >
> > > CodeGen wants registers to be spilled at the end of a block.
> >
> > That's fast reg alloc only. What is happening with the other allocators?
>
>
> They don't appear to use the correct registers for the defined values.


I should probably explain a bit better. With a normal `INLINEASM` instruction, any defined registers are spilled directly afterwards. This is one reason why I want to do the same for `INLINEASM_BR` with the `TCOPY`. There could be other ways to achieve the same thing, but I think it would involve placing a larger burden on the code generation passes than needs be.


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