[llvm] [X86][MC] Support Enc/Dec for NF for promoted BMI instructions in 73899 (PR #76709)

[Shengchen Kan via llvm-commits]

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@@ -1134,6 +1134,21 @@ static int getInstructionIDWithAttrMask(uint16_t *instructionID,
   return 0;
 }
 
+static bool isNFnotMap4(InternalInstruction *insn) {
+  // Promoted BMI instrs below has nf version.
+  if (insn->opcodeType == THREEBYTE_38 &&
+      ppFromXOP3of3(insn->vectorExtensionPrefix[2]) == VEX_PREFIX_NONE) {
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KanRobert wrote:

I don't understand. Why do you call function `ppFromXOP3of3` for NF instructions? I remember intel does not support `XOP`.

https://github.com/llvm/llvm-project/pull/76709