[clang] [llvm] [ARM] Introduce intrinsics for MVE minnm/maxnm under strict-fp. (PR #169795)

[David Green via llvm-commits]

davemgreen wrote:

> Should not introduce new target intrinsics for strictfp. Target intrinsics do not work with strictfp at all today. These have no chains and will be freely reordered. It's also not reasonable to duplicate every floating point math intrinsic, which is the point of the proposed change to start using operand bundles for strictfp

For MVE the list is not that long, and we need some way of preventing the intrinsics from scalarizing into multiple ops. So we either convert fadd into vadd, which does not obey the rounding modes so is not correct (not to mention denormals - those have always been bad in llvm). So we introduce intrinsics and at least not have them scalarize. I believe we will need them independent of what happens with operand bundles, and are stuck not being able to enable the feature in the short term if not.

https://github.com/llvm/llvm-project/pull/169795