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Description
This is a reduced output from a fuzzer that generates Rust MIR, https://github.com/cbeuw/rustlantis
I've been running rustlantis using a rustc built against the tip of LLVM's main branch. This example compiles fine on Rust nightly:
https://godbolt.org/z/oWzs5PM19
Use the flags
-Zmir-opt-level=0 -Copt-level=3 -Cno-prepopulate-passes
Some -opt-bisect-limit indicates that compilation goes awry in Machine Copy Propagation. Since this is a recent regression, I think the cause is somehow related to #140267 (of course I have no idea whether that PR added a bug or made it easier for rustlantis to hit an existing one).