Index: llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ llvm/trunk/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1049,8 +1049,8 @@
     .Cases("WORD", "word", 16)
     .Cases("DWORD", "dword", 32)
     .Cases("QWORD", "qword", 64)
+    .Cases("MMWORD","mmword", 64)
     .Cases("XWORD", "xword", 80)
-    //
     .Cases("TBYTE", "tbyte", 80)
     .Cases("XMMWORD", "xmmword", 128)
     .Cases("YMMWORD", "ymmword", 256)
Index: llvm/trunk/test/MC/X86/intel-syntax.s
===================================================================
--- llvm/trunk/test/MC/X86/intel-syntax.s
+++ llvm/trunk/test/MC/X86/intel-syntax.s
@@ -705,6 +705,9 @@
 sal eax, 123
 // CHECK: shll	$123, %eax
 
+psignw    mm0, MMWORD PTR t2
+// CHECK: psignw t2, %mm0
+
 comisd xmm0, QWORD PTR [eax]
 comiss xmm0, DWORD PTR [eax]
 vcomisd xmm0, QWORD PTR [eax]