Miscompilation with target-cpu=znver1 (AMD Ryzen 1000/2000 series) on Windows + LLVM 9. #63959
Description
On any recent MSVC nightly, compiling with release profile with RUSTFLAGS = "-C target-cpu=native" results in either STATUS_ACCESS_VIOLATION or STATUS_HEAP_CORRUPTION depending on the crate. Many crates work, but others don't. Among those that fail some use SIMD. target-cpu=native resolves to target-cpu=znver1 on my machine.
This seems to be related #63361 and the LLVM upgrade, again. It does not happen when target-cpu is not set.
Everything works on 07e0c36 but fails after 38798c6, same as the aforementioned issue. I am not sure how to reproduce it in a single crate, but I will look into it.
LLVM 9 just doesn't like AMD.
Although, another issue of mine: bytecodealliance/cranelift#900 also fails in a similar manner before the LLVM upgrade, so it's worth noting.