[llvm] [NVPTX] Generalize and extend upsizing when lowering 8/16-bit-element vector loads/stores (PR #119622)

[Drew Kersnar via llvm-commits]

================
@@ -3185,10 +3205,15 @@ NVPTXTargetLowering::LowerSTOREVector(SDValue Op, SelectionDAG &DAG) const {
     case MVT::v4f16:
     case MVT::v4bf16:
     case MVT::v4f32:
-    case MVT::v8f16: // <4 x f16x2>
+      // This is a "native" vector type
+      break;
+    case MVT::v8i8:   // <2 x i8x4>
+    case MVT::v8f16:  // <4 x f16x2>
     case MVT::v8bf16: // <4 x bf16x2>
     case MVT::v8i16:  // <4 x i16x2>
-      // This is a "native" vector type
+    case MVT::v16i8:  // <4 x i8x4>
+      // This can be upsized into a "native" vector type
+      UpsizeElementTypes = true;
----------------
dakersnar wrote:

I think there's a misunderstanding; I was referring to cases that are neither native _nor_ upsize-able. This switch statement has two functions right now, marking the cases that we need to upsize, and returning early for cases that cannot be handled at all, such as `v8i32`. How will we handle the latter with the helper function approach, besides making it a "Try" function and adding another boolean to the returns?

https://github.com/llvm/llvm-project/pull/119622