[X86] Move 'int $3' -> 'int3' handling in the assembler to processInstruction.

Instead of handling before parsing, just fix it after parsing.

Author: topperc

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -3305,18 +3305,6 @@ bool X86AsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
     return HadVerifyError;
   }
 
-  // Transforms "int $3" into "int3" as a size optimization.  We can't write an
-  // instalias with an immediate operand yet.
-  if (Name == "int" && Operands.size() == 2) {
-    X86Operand &Op1 = static_cast<X86Operand &>(*Operands[1]);
-    if (Op1.isImm())
-      if (auto *CE = dyn_cast<MCConstantExpr>(Op1.getImm()))
-        if (CE->getValue() == 3) {
-          Operands.erase(Operands.begin() + 1);
-          static_cast<X86Operand &>(*Operands[0]).setTokenValue("int3");
-        }
-  }
-
   // Transforms "xlat mem8" into "xlatb"
   if ((Name == "xlat" || Name == "xlatb") && Operands.size() == 2) {
     X86Operand &Op1 = static_cast<X86Operand &>(*Operands[1]);
@@ -3521,6 +3509,17 @@ bool X86AsmParser::processInstruction(MCInst &Inst, const OperandVector &Ops) {
     Inst = TmpInst;
     return true;
   }
+  case X86::INT: {
+    // Transforms "int $3" into "int3" as a size optimization.  We can't write an
+    // instalias with an immediate operand yet.
+    if (!Inst.getOperand(0).isImm() || Inst.getOperand(0).getImm() != 3)
+      return false;
+
+    MCInst TmpInst;
+    TmpInst.setOpcode(X86::INT3);
+    Inst = TmpInst;
+    return true;
+  }
   }
 }