Index: utils/TableGen/AsmMatcherEmitter.cpp
===================================================================
--- utils/TableGen/AsmMatcherEmitter.cpp
+++ utils/TableGen/AsmMatcherEmitter.cpp
@@ -1851,7 +1851,7 @@
   CvtOS << "  Inst.setOpcode(Opcode);\n";
   CvtOS << "  for (const uint8_t *p = Converter; *p; p+= 2) {\n";
   if (HasOptionalOperands) {
-    CvtOS << "    OpIdx = *(p + 1) - NumDefaults;\n";
+    CvtOS << "    OpIdx = *(p + 1) - countPopulation(NumDefaults<<(sizeof(unsigned)*8-1-p[1]));\n";
   } else {
     CvtOS << "    OpIdx = *(p + 1);\n";
   }
@@ -1986,7 +1986,7 @@
                 << "        " << Op.Class->DefaultMethod << "()"
                 << "->" << Op.Class->RenderMethod << "(Inst, "
                 << OpInfo.MINumOperands << ");\n"
-                << "        ++NumDefaults;\n"
+                << "        NumDefaults |= 1<<(p[1]+1);\n"
                 << "      } else {\n"
                 << "        static_cast<" << TargetOperandClass
                 << "&>(*Operands[OpIdx])." << Op.Class->RenderMethod