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/X86InstrInfo.h b/lib/Target/X86/X86InstrInfo.h
index 9f50178..5111719 100644
--- a/lib/Target/X86/X86InstrInfo.h
+++ b/lib/Target/X86/X86InstrInfo.h
@@ -279,6 +279,7 @@
     MRM_E8 = 39,
     MRM_F0 = 40,
     MRM_F8 = 41,
+    MRM_F9 = 42,
 
     FormMask       = 63,