diff --git a/llvm/lib/Target/X86/X86ATTAsmPrinter.cpp b/llvm/lib/Target/X86/X86ATTAsmPrinter.cpp
index 065587712405..cc4252fc47c2 100644
--- a/llvm/lib/Target/X86/X86ATTAsmPrinter.cpp
+++ b/llvm/lib/Target/X86/X86ATTAsmPrinter.cpp
@@ -521,6 +521,9 @@ bool X86ATTAsmPrinter::printAsmMRegister(const MachineOperand &MO,
   case 'k': // Print SImode register
     Reg = getX86SubSuperRegister(Reg, MVT::i32);
     break;
+  case 'q': // Print DImode register
+    Reg = getX86SubSuperRegister(Reg, MVT::i64);
+    break;
   }
 
   O << '%';
@@ -547,6 +550,7 @@ bool X86ATTAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
     case 'h': // Print QImode high register
     case 'w': // Print HImode register
     case 'k': // Print SImode register
+    case 'q': // Print DImode register
       if (MI->getOperand(OpNo).isRegister())
         return printAsmMRegister(MI->getOperand(OpNo), ExtraCode[0]);
       printOperand(MI, OpNo);
@@ -566,8 +570,20 @@ bool X86ATTAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
                                              unsigned OpNo,
                                              unsigned AsmVariant, 
                                              const char *ExtraCode) {
-  if (ExtraCode && ExtraCode[0])
-    return true; // Unknown modifier.
+  if (ExtraCode && ExtraCode[0]) {
+    if (ExtraCode[1] != 0) return true; // Unknown modifier.
+    
+    switch (ExtraCode[0]) {
+    default: return true;  // Unknown modifier.
+    case 'b': // Print QImode register
+    case 'h': // Print QImode high register
+    case 'w': // Print HImode register
+    case 'k': // Print SImode register
+    case 'q': // Print SImode register
+      // These only apply to registers, ignore on mem.
+      break;
+    }
+  }
   printMemReference(MI, OpNo);
   return false;
 }
diff --git a/llvm/test/CodeGen/X86/2007-10-28-inlineasm-q-modifier.ll b/llvm/test/CodeGen/X86/2007-10-28-inlineasm-q-modifier.ll
new file mode 100644
index 000000000000..450911ae8199
--- /dev/null
+++ b/llvm/test/CodeGen/X86/2007-10-28-inlineasm-q-modifier.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | llc
+; PR1748
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @kernel_init(i8* %unused) {
+entry:
+	call void asm sideeffect "foo ${0:q}", "=*imr"( i64* null )
+	ret i32 0
+}
+