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

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D75098#2049787 <https://reviews.llvm.org/D75098#2049787>, @qcolombet wrote:

> > Regardless of what happens to INLINEASM_BR, I think we still need a terminator copy
>
> What for?
>  The whole concept is bogus to me because if the previous instructions are really terminators (as in they branch to somewhere else), then this copy would never be executed.


Terminator does not imply a branch, it only means glued to the end of the block. It's the only way to get correct spill code placement around exec mask writes. We need a copy to the exec mask, but spill code needs to be inserted before that point. Currently we get unnecessary copies since we use a raw move instructions for this purpose, when we could have coalesced a copy


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https://reviews.llvm.org/D75098