[X86] Fix disassembly of EVEX rounding control and SAE instructions.

Fixes PR31955.

llvm-svn: 316308
diff --git a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
index e38c0bc..c58254a 100644
--- a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -959,6 +959,9 @@
                        insn,
                        Dis);
     return false;
+  case ENCODING_IRC:
+    mcInst.addOperand(MCOperand::createImm(insn.RC));
+    return false;
   case ENCODING_SI:
     return translateSrcIndex(mcInst, insn);
   case ENCODING_DI: