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

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

Probably best just to early out if VT total size is less than 128 or not a power of 2. We can improve handling later. We need that test coverage though.

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