[llvm] [AMDGPU] Add `isAsCheapAsAMove` for `v_pk_mov_b32` (PR #127632)

[Shilei Tian via llvm-commits]

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@@ -1151,7 +1151,7 @@ let isCommutable = 1, isReMaterializable = 1 in {
     defm V_PK_ADD_F32 : VOP3PInst<"v_pk_add_f32", VOP3P_Profile<VOP_V2F32_V2F32_V2F32, VOP3_PACKED>, any_fadd>;
   } // End SubtargetPredicate = HasPackedFP32Ops
 
-  let SubtargetPredicate = HasPkMovB32 in
+  let SubtargetPredicate = HasPkMovB32, isAsCheapAsAMove = 1 in
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shiltian wrote:

There is no test change but how to test it?

https://github.com/llvm/llvm-project/pull/127632