assigned to @MatzeB

This is a reduced testcase from an OpenCV regression

Is this new?
I.e., is this a regression and if yes, what introduced it?

Is this new?
I.e., is this a regression and if yes, what introduced it?

The regression showed up in r251860, so I think this was uncovering a existing problem.

I think this bug always existed, it only affects targets with acticated subregister liveness. We already had a longer IRC session analyzing it (just have to grep my logs when I start working on it), so I'll look into it.

I think this bug always existed, it only affects targets with acticated
subregister liveness. We already had a longer IRC session analyzing it (just
have to grep my logs when I start working on it), so I'll look into it.

Sounds good.
Thanks both.

For the sake of future archeology ;), would you mind summarizing the content of the IRC discussion?

For the sake of future archeology ;), would you mind summarizing the content of the IRC discussion?

Sorry I can't remember the details (intricate stuff in the rematerialization logic of the register coalescer). Once there is a fix it is hopefully clear that the problem was :)

For the sake of future archeology ;), would you mind summarizing the content of the IRC discussion?

Sorry I can't remember the details (intricate stuff in the rematerialization
logic of the register coalescer). Once there is a fix it is hopefully clear
that the problem was :)

Fair enough :).

Fixed in r262768