[llvm] [X86][MC] Compress APX Promoted instrs from evex to legacy encoding to save code size. (PR #77065)

[Shengchen Kan via llvm-commits]

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@@ -2060,6 +2060,8 @@ void X86AsmPrinter::emitInstruction(const MachineInstr *MI) {
   if (TM.Options.MCOptions.ShowMCEncoding) {
     if (MI->getAsmPrinterFlags() & X86::AC_EVEX_2_VEX)
       OutStreamer->AddComment("EVEX TO VEX Compression ", false);
+    else if (MI->getAsmPrinterFlags() & X86::AC_EVEX_2_LEGACY)
+      OutStreamer->AddComment("EVEX TO LEGACY Compression ", false);
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KanRobert wrote:

Check if it's VEX encoding and if not emits "EVEX TO LEGACY Compression"

https://github.com/llvm/llvm-project/pull/77065