[llvm] [AMDGPU] Add custom lowering for E5M3 path for packed convert instructions through `convert.{to|from}.arbitrary.fp` (PR #218056)

[Krzysztof Drewniak via llvm-commits]

================
@@ -108,7 +108,8 @@ class SITargetLowering final : public AMDGPUTargetLowering {
   SDValue LowerCONVERT_FROM_ARBITRARY_FP(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerFromFP8(SDValue Op, bool IsBF8, SelectionDAG &DAG) const;
   SDValue LowerCONVERT_TO_ARBITRARY_FP(SDValue Op, SelectionDAG &DAG) const;
-  SDValue lowerToFP8(SDValue Op, bool IsBF8, SelectionDAG &DAG) const;
+  SDValue lowerToFP8(SDValue Op, bool IsBF8, bool IsE5M3,
----------------
krzysz00 wrote:

The booleans here feel wrong - you might want an enum or something?

https://github.com/llvm/llvm-project/pull/218056