Backport "[AVR] Fix 16-bit LDDs with immediate overflows (#104923)"

[tronje]

/cherry-pick c7a4efa

I initially spotted and reported the bug here: Rahix/avr-hal#573
Thanks to @Patryk27 there's a fix that has even been merged already, but I really need this to make its way into a Rust toolchain 🙂
So I did some digging and basically copied #106728 and am hereby requesting a backport of this into the release branch. Hope I'm doing this right! Thanks!

Edit: looks like I'm unable to set the correct milestone, any help? 🙏

[llvmbot]

/cherry-pick c7a4efa

I initially spotted and reported the bug here: Rahix/avr-hal#573
Thanks to @Patryk27 there's a fix that has even been merged already, but I really need this to make its way into a Rust toolchain 🙂
So I did some digging and basically copied #106728 and am hereby requesting a backport of this into the release branch. Hope I'm doing this right! Thanks!

Error: Command failed due to missing milestone.

[Patryk27]

fwiw, it needs to be cherry-picked into https://github.com/rust-lang/llvm-project (https://rustc-dev-guide.rust-lang.org/backend/updating-llvm.html) to actually land in rustc.

I was planning on doing that later, since we've gotta bundle that commit together with #106729 to actually get the codegen working.

[tronje]

fwiw, it needs to be cherry-picked into https://github.com/rust-lang/llvm-project (https://rustc-dev-guide.rust-lang.org/backend/updating-llvm.html) to actually land in rustc.

Yeah I know, but the dev guide says to request a backport upstream first, so I figured I'd do that.

I was planning on doing that later, since we've gotta bundle that commit together with #106729 to actually get the codegen working.

Ah okay; is there anything at all that I can do? 🙂

[Patryk27]

Not sure, probably @aykevl can help us the most here - could you backport #104923? 😄

It looks like we're just missing the milestone label here, but I'm not sure on the backporting process.

[aykevl]

Added the milestone, let's see whether it helps.

[EugeneZelenko]

/cherry-pick c7a4efa

[llvmbot]

/pull-request #106993