[llvm] selecting v_sat_pk instruction, version 2 (PR #123297)

[Pierre van Houtryve via llvm-commits]

================
@@ -5498,6 +5498,7 @@ const char* AMDGPUTargetLowering::getTargetNodeName(unsigned Opcode) const {
   NODE_NAME_CASE(UMIN3)
   NODE_NAME_CASE(FMED3)
   NODE_NAME_CASE(SMED3)
+  NODE_NAME_CASE(SAT_PK_CAST)
----------------
Pierre-vh wrote:

Why do we need this extra node, can't we just select from `TRUNC_SSAT_U` directly?
Is it because it gets transformed/lost otherwise?

https://github.com/llvm/llvm-project/pull/123297