[llvm] [X86][MC] Support encoding/decoding for APX variant ADD/SUB/ADC/SBB/OR/XOR/NEG/NOT instructions (PR #76319)

[Phoebe Wang via llvm-commits]

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@@ -3996,6 +4001,8 @@ unsigned X86AsmParser::checkTargetMatchPredicate(MCInst &Inst) {
 
   if (UseApxExtendedReg && !X86II::canUseApxExtendedReg(MCID))
     return Match_Unsupported;
+  if (ForcedNoFlag != static_cast<bool>(MCID.TSFlags & X86II::EVEX_NF))
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phoebewang wrote:

`{evex}` doesn't check in this way. Given a asm string without `{nf}`, it should be selected to non-NF instruction, otherwise, there's something wrong during match instruction. That's why I think it just need to assert for this case.

https://github.com/llvm/llvm-project/pull/76319