Implement the rex64 prefix.

llvm-svn: 120017

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

@@ -707,7 +707,8 @@ ParseInstruction(StringRef Name, SMLoc NameLoc,
   bool isPrefix =
     Name == "lock" || Name == "rep" ||
     Name == "repe" || Name == "repz" ||
-    Name == "repne" || Name == "repnz";
+    Name == "repne" || Name == "repnz" ||
+    Name == "rex64";
 
 
   // This does the actual operand parsing.  Don't parse any more if we have a

llvm/lib/Target/X86/X86InstrInfo.td

@@ -1144,6 +1144,9 @@ def CMPXCHG16B : RI<0xC7, MRM1m, (outs), (ins i128mem:$dst),
 // Lock instruction prefix
 def LOCK_PREFIX : I<0xF0, RawFrm, (outs),  (ins), "lock", []>;
 
+// Rex64 instruction prefix
+def REX64_PREFIX : I<0x48, RawFrm, (outs),  (ins), "rex64", []>;
+
 // Repeat string operation instruction prefixes
 // These uses the DF flag in the EFLAGS register to inc or dec ECX
 let Defs = [ECX], Uses = [ECX,EFLAGS] in {