Runtime code is generated for functions only used in const eval

Code

I tried this code:

• https://godbolt.org/z/M33K6afz8
• https://play.rust-lang.org/?version=beta&mode=release&edition=2018&gist=095cc1d85dfd25b5dd1bc742fbf98432

I expected to see this happen: Both check1 and check2 should compile to functions that just use a compiletime-evaluated struct value

Instead, this happened: check1 disapeared from the assembly, and it looks like all the code needed to runtime-evaluate it got added instead

The weird thing is that the function that regressed is the one that uses a const item by name, rather than the one that just calls a const function inside a non-const function body.

Version it worked on

It most recently worked on: 1.74.1 (stable as of writing this)

Version with regression

from playground:

1.76.0-beta.1 (2023-12-21 0e09125c6c3c2fd70d7d)
1.77.0-nightly (2023-12-21 3d0e6bed600c0175628e)

Start with the linked Godbolt and Rust Playground reproductions, comparing stable 1.74.1 with the listed beta and nightly versions and inspecting the generated assembly. Trace the compiler behavior for the named const item versus the direct const-function call. Done means both functions compile to code using the compile-time-evaluated value without unnecessary runtime evaluation.