AVX512 test runs on machine without AVX512

[rengolin]

Machine: AMD EPYC 7742 64-Core Processor Extension: avx2 Test: BF16/Integration/vector-contract-to-bf16dp.mlir Error:

SplitVectorResult #0: t40: v16f32 = llvm.x86.avx512bf16.dpbf16ps.512 TargetConstant:i64<14225>, t39, t15, t32

LLVM ERROR: Do not know how to split the result of this operator!

Some error while detecting AVX512 to enable the pass. It should return matchFailure if there's no AVX512 on the target specification.

[shahidact]

I could not reproduce this issue on compile node.

[adam-smnk]

I think #1031 solved it