[llvm] [X86] Support EGPR (R16-R31) for APX (PR #67702)

[Phoebe Wang via llvm-commits]

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@@ -150,6 +150,11 @@ class X86InstrInfo final : public X86GenInstrInfo {
 public:
   explicit X86InstrInfo(X86Subtarget &STI);
 
+  const TargetRegisterClass *
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phoebewang wrote:

Add doxygen for it.

https://github.com/llvm/llvm-project/pull/67702