tblgen/Target: Add a isAsmParserOnly bit, and teach the disassembler to honor

it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104270 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/Target.td

@@ -221,6 +221,9 @@ class Instruction {
   // purposes.
   bit isCodeGenOnly = 0;
 
+  // Is this instruction a pseudo instruction for use by the assembler parser.
+  bit isAsmParserOnly = 0;
+
   InstrItinClass Itinerary = NoItinerary;// Execution steps used for scheduling.
 
   string Constraints = "";  // OperandConstraint, e.g. $src = $dst.

utils/TableGen/X86RecognizableInstr.cpp

@@ -230,6 +230,10 @@ void RecognizableInstr::processInstr(DisassemblerTables &tables,
                                    const CodeGenInstruction &insn,
                                    InstrUID uid)
 {
+  // Ignore "asm parser only" instructions.
+  if (insn.TheDef->getValueAsBit("isAsmParserOnly"))
+    return;
+  
   RecognizableInstr recogInstr(tables, insn, uid);
   
   recogInstr.emitInstructionSpecifier(tables);