[llvm] [X86][MC] Support encoding/decoding for APX variant INC/DEC/ADCX/ADOX instructions (PR #76721)

[Phoebe Wang via llvm-commits]

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@@ -184,52 +184,139 @@ def IMUL64rmi32 : IMulOpMI_R<Xi64, WriteIMul64Imm>;
 //===----------------------------------------------------------------------===//
 // INC and DEC Instructions
 //
-class IncOpR_RF<X86TypeInfo t> : UnaryOpR_RF<0xFF, MRM0r, "inc", t, null_frag> {
+class IncOpR_RF<X86TypeInfo t, bit ndd = 0> : UnaryOpR_RF<0xFF, MRM0r, "inc", t, null_frag, ndd> {
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phoebewang wrote:

I can understand the last `F` means eflags, what's the mean of `R_R`, `M_M`, `M_R`..?

https://github.com/llvm/llvm-project/pull/76721