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

[Matt Arsenault via llvm-commits]

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@@ -3309,6 +3309,21 @@ def : GCNPat <
   (v2i16 (V_LSHL_OR_B32_e64 $src1, (i32 16), (i32 (V_AND_B32_e64 (i32 (V_MOV_B32_e32 (i32 0xffff))), $src0))))
 >;
 
+multiclass V_SAT_PK_Pat<Instruction inst> {
+  def : GCNPat<
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arsenm wrote:

The node is basically the same as the instruction definition, so you should be able to use the built-in pattern attached to the instruction def. 
Something like

`  defm V_SAT_PK_U8_I16    : VOP1Inst_t16<"v_sat_pk_u8_i16", VOP_I16_I32, AMDGPUsat_pk_cast>;`

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