The T26410_ffi test seems to occasionally segfault on Windows in the `optllvm` way, as can be see in [this pipeline](https://gitlab.haskell.org/ghc/ghc/-/jobs/2342689#L6342): ``` Wrong exit code for T26410_ffi(optllvm)(expected 0 , actual 11 ) Stderr comp ( T26410_ffi ): [1 of 2] Compiling Main ( T26410_ffi.hs, T26410_ffi.o ) [2 of 2] Linking T26410_ffi.exe Stderr run ( T26410_ffi ): Access violation in generated code when reading 0xfffffffffffffff8 Attempting to reconstruct a stack trace... Frame Code address * 0xdc3cb6d6a0 0x7ff796753d8a C:\GitLabRunner\builds\0\2342689\tmp\ghctest-9rokpjdz\test spaces\testsuite\tests\simd\should_run\T26410_ffi.run\T26410_ffi.exe+0x1c3d8a * 0xdc3cb6d6a8 0x7ff79674aa5a C:\GitLabRunner\builds\0\2342689\tmp\ghctest-9rokpjdz\test spaces\testsuite\tests\simd\should_run\T26410_ffi.run\T26410_ffi.exe+0x1baa5a * 0xdc3cb6d6b0 0x8 * 0xdc3cb6d6b8 0xdc3cb6d7a8 *** unexpected failure for T26410_ffi(optllvm) ``` This looks to me like it could be an issue with saving/restoring registers to the stack around a foreign call.