diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 619567665a9..f166b9bc003 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -614,7 +614,8 @@ bool X86DAGToDAGISel::MatchAddress(SDOperand N, X86ISelAddressMode &AM,
       bool isStatic = TM.getRelocationModel() == Reloc::Static;
       SDOperand N0 = N.getOperand(0);
       // Mac OS X X86-64 lower 4G address is not available.
-      bool isAbs32 = !is64Bit || (isStatic && !Subtarget->isTargetDarwin());
+      bool isAbs32 = !is64Bit ||
+        (isStatic && Subtarget->hasLow4GUserSpaceAddress());
       if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
         GlobalValue *GV = G->getGlobal();
         if (isAbs32 || isRoot) {
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index ab2c8dc1094..190d5b1bcc0 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -162,6 +162,7 @@ def HasSSSE3     : Predicate<"Subtarget->hasSSSE3()">;
 def FPStack      : Predicate<"!Subtarget->hasSSE2()">;
 def In32BitMode  : Predicate<"!Subtarget->is64Bit()">;
 def In64BitMode  : Predicate<"Subtarget->is64Bit()">;
+def HasLow4G     : Predicate<"Subtarget->hasLow4GUserSpaceAddress()">;
 def SmallCode    : Predicate<"TM.getCodeModel() == CodeModel::Small">;
 def NotSmallCode : Predicate<"TM.getCodeModel() != CodeModel::Small">;
 def IsStatic     : Predicate<"TM.getRelocationModel() == Reloc::Static">;
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index 1a75e04511b..51406c39279 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -225,6 +225,7 @@ X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
   // FIXME: this is a known good value for Yonah. How about others?
   , MinRepStrSizeThreshold(128)
   , Is64Bit(is64Bit)
+  , HasLow4GUserAddress(true)
   , TargetType(isELF) { // Default to ELF unless otherwise specified.
 
   // Determine default and user specified characteristics
@@ -285,6 +286,9 @@ X86Subtarget::X86Subtarget(const Module &M, const std::string &FS, bool is64Bit)
     }
   }
 
+  if (TargetType == isDarwin && Is64Bit)
+    HasLow4GUserAddress = false;
+
   if (TargetType == isDarwin ||
       TargetType == isCygwin ||
       TargetType == isMingw  ||
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index 2cda9705e31..6240dc2715a 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -46,18 +46,23 @@ protected:
   };
 
   /// AsmFlavor - Which x86 asm dialect to use.
+  ///
   AsmWriterFlavorTy AsmFlavor;
 
   /// PICStyle - Which PIC style to use
+  ///
   PICStyle::Style PICStyle;
   
   /// X86SSELevel - MMX, SSE1, SSE2, SSE3, SSSE3, or none supported.
+  ///
   X86SSEEnum X86SSELevel;
 
   /// X863DNowLevel - 3DNow or 3DNow Athlon, or none supported.
+  ///
   X863DNowEnum X863DNowLevel;
 
   /// HasX86_64 - True if the processor supports X86-64 instructions.
+  ///
   bool HasX86_64;
 
   /// stackAlignment - The minimum alignment known to hold of the stack frame on
@@ -65,6 +70,7 @@ protected:
   unsigned stackAlignment;
 
   /// Min. memset / memcpy size that is turned into rep/movs, rep/stos ops.
+  ///
   unsigned MinRepStrSizeThreshold;
 
 private:
@@ -72,6 +78,10 @@ private:
   /// pointer size is 64 bit.
   bool Is64Bit;
 
+  /// HasLow4GUserAddress - True if the low 4G user-space address is available.
+  ///
+  bool HasLow4GUserAddress;
+
 public:
   enum {
     isELF, isCygwin, isDarwin, isWindows, isMingw
@@ -103,6 +113,10 @@ public:
 
   bool is64Bit() const { return Is64Bit; }
 
+  /// hasLow4GUserSpaceAddress - True if lower 4G user-space address is
+  /// available.
+  bool hasLow4GUserSpaceAddress() const { return HasLow4GUserAddress; }
+
   PICStyle::Style getPICStyle() const { return PICStyle; }
   void setPICStyle(PICStyle::Style Style)  { PICStyle = Style; }