[llvm] [RISCV][TableGen] Return instruction size from isCompressibleInst (PR #225660)

[Sam Elliott via llvm-commits]

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@@ -633,7 +633,9 @@ void CompressInstEmitter::emitCompressInstEmitter(raw_ostream &OS,
     FuncH.indent(27) << "const MCSubtargetInfo &STI) {\n";
   } else if (EType == EmitterType::CheckCompress) {
     FuncH << "static bool isCompressibleInst(const MachineInstr &MI,\n";
-    FuncH.indent(31) << "const " << TargetName << "Subtarget &STI) {\n";
+    FuncH.indent(31) << "const " << TargetName << "Subtarget &STI,\n";
+    FuncH.indent(31) << "unsigned *Size = nullptr) {\n";
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lenary wrote:

I'm not entirely sure. It might be worth starting a huge paragraph before the `CompressPat` class definition in tablegen, but I don't know. 

https://github.com/llvm/llvm-project/pull/225660