add encoder support and tests for rdtscp


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96076 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86MCCodeEmitter.cpp b/lib/Target/X86/X86MCCodeEmitter.cpp
index 1dc592c..2c7b9d8 100644
--- a/lib/Target/X86/X86MCCodeEmitter.cpp
+++ b/lib/Target/X86/X86MCCodeEmitter.cpp
@@ -617,6 +617,10 @@
     EmitByte(BaseOpcode, CurByte, OS);
     EmitByte(0xF8, CurByte, OS);
     break;
+  case X86II::MRM_F9:
+    EmitByte(BaseOpcode, CurByte, OS);
+    EmitByte(0xF9, CurByte, OS);
+    break;
   }
   
   // If there is a remaining operand, it must be a trailing immediate.  Emit it