diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index c370371e864..5d6048616b6 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1247,6 +1247,7 @@ static unsigned getIntelMemOperandSize(StringRef OpStr) {
     .Cases("XMMWORD", "xmmword", 128)
     .Cases("YMMWORD", "ymmword", 256)
     .Cases("ZMMWORD", "zmmword", 512)
+    .Cases("OPAQUE", "opaque", -1U) // needs to be non-zero, but doesn't matter
     .Default(0);
   return Size;
 }
diff --git a/test/MC/X86/intel-syntax.s b/test/MC/X86/intel-syntax.s
index dba72b3dcd0..0f75d5d82a5 100644
--- a/test/MC/X86/intel-syntax.s
+++ b/test/MC/X86/intel-syntax.s
@@ -588,5 +588,5 @@ fdivr ST(1)
 
 // CHECK: fxsaveq (%rax)
 // CHECK: fxrstorq (%rax)
-fxsave64 [rax]
-fxrstor64 [rax]
+fxsave64 opaque ptr [rax]
+fxrstor64 opaque ptr [rax]