Codegen regression from stable to nightly and beta

[newpavlov]

While discussing potential alternative implementations for array::map in #102202, the following regression was discovered on nigthly/beta: https://rust.godbolt.org/z/h39Tr776T See assembly for foo2, it should be identical to foo1, but for some reason compiler was unable to eliminate panics. Switching toolchain to 1.64 results in expected efficient assembly.

[the8472]

Using for_each instead of for (i, x) in works. LLVM has issues with that pattern #92174

[newpavlov]

It looks like the issue was fixed in Rust 1.69.