[llvm] [X86] Recognise VPMADD52L pattern with AVX512IFMA/AVXIFMA (#153787) (PR #156714)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon requested changes to this pull request.

Please can you add a couple of tests for odd types that satisfy the knownbits (<1 x i64> and <6 x i64> might be good examples)

https://github.com/llvm/llvm-project/pull/156714