[llvm] [MIR] Serialize virtual register flags (PR #110228)

[Matt Arsenault via llvm-commits]

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@@ -206,6 +207,8 @@ template <> struct MappingTraits<VirtualRegisterDefinition> {
     YamlIO.mapRequired("class", Reg.Class);
     YamlIO.mapOptional("preferred-register", Reg.PreferredRegister,
                        StringValue()); // Don't print out when it's empty.
+    YamlIO.mapOptional("flags", Reg.RegisterFlags,
+                       std::vector<FlowStringValue>());
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arsenm wrote:

Can this be just {}

https://github.com/llvm/llvm-project/pull/110228