[llvm] [AMDGPU][NFC] Extend PredicateControl to support True16 predicates. (PR #82245)

[Ivan Kosarev via llvm-commits]

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@@ -1484,8 +1484,8 @@ multiclass VOP3_Real_dpp8_with_name<GFXGen Gen, bits<10> op, string opName,
   let AsmString = asmName # ps.Pfl.AsmVOP3DPP8,
       DecoderNamespace = "DPP8"#Gen.DecoderNamespace#
                          !if(ps.Pfl.IsRealTrue16, "", "_FAKE16"),
-      OtherPredicates = !if(ps.Pfl.IsRealTrue16, [UseRealTrue16Insts],
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kosarev wrote:

In real instructions we can paste with `OtherPredicates` of their pseudos, but there's no way to extend self `OtherPredicates` of classes and records. So every `let OtherPredicates = ...` potentially overrides some needed predicates and so having `True16Predicate` makes it a bit easier to avoid clashes.

https://github.com/llvm/llvm-project/pull/82245