diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9078c6f..1d3fa28 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5128,15 +5128,17 @@
 
 SDValue
 X86TargetLowering::EmitTargetCodeForMemset(SelectionDAG &DAG,
-                                        SDValue Chain,
-                                        SDValue Dst, SDValue Src,
-                                        SDValue Size, unsigned Align,
-                                        const Value *DstSV, uint64_t DstSVOff) {
+                                           SDValue Chain,
+                                           SDValue Dst, SDValue Src,
+                                           SDValue Size, unsigned Align,
+                                           const Value *DstSV,
+                                           uint64_t DstSVOff,
+                                           bool NoBuiltin) {
   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
 
-  /// If not DWORD aligned or size is more than the threshold, call the library.
-  /// The libc version is likely to be faster for these cases. It can use the
-  /// address value and run time information about the CPU.
+  // If not DWORD aligned or size is more than the threshold, call the library.
+  // The libc version is likely to be faster for these cases. It can use the
+  // address value and run time information about the CPU.
   if ((Align & 3) != 0 ||
       !ConstantSize ||
       ConstantSize->getZExtValue() >
@@ -5145,8 +5147,9 @@
 
     // Check to see if there is a specialized entry-point for memory zeroing.
     ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
-    if (const char *bzeroEntry = 
-          V && V->isNullValue() ? Subtarget->getBZeroEntry() : 0) {
+
+    if (const char *bzeroEntry =  V &&
+        V->isNullValue() ? Subtarget->getBZeroEntry(NoBuiltin) : 0) {
       MVT IntPtr = getPointerTy();
       const Type *IntPtrTy = TD->getIntPtrType();
       TargetLowering::ArgListTy Args; 
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index dac0da7..5cdb65d 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -575,17 +575,18 @@
     SDNode *ExpandATOMIC_CMP_SWAP(SDNode *N, SelectionDAG &DAG);
     
     SDValue EmitTargetCodeForMemset(SelectionDAG &DAG,
-                                      SDValue Chain,
-                                      SDValue Dst, SDValue Src,
-                                      SDValue Size, unsigned Align,
-                                      const Value *DstSV, uint64_t DstSVOff);
+                                    SDValue Chain,
+                                    SDValue Dst, SDValue Src,
+                                    SDValue Size, unsigned Align,
+                                    const Value *DstSV, uint64_t DstSVOff,
+                                    bool NoBuiltin);
     SDValue EmitTargetCodeForMemcpy(SelectionDAG &DAG,
-                                      SDValue Chain,
-                                      SDValue Dst, SDValue Src,
-                                      SDValue Size, unsigned Align,
-                                      bool AlwaysInline,
-                                      const Value *DstSV, uint64_t DstSVOff,
-                                      const Value *SrcSV, uint64_t SrcSVOff);
+                                    SDValue Chain,
+                                    SDValue Dst, SDValue Src,
+                                    SDValue Size, unsigned Align,
+                                    bool AlwaysInline,
+                                    const Value *DstSV, uint64_t DstSVOff,
+                                    const Value *SrcSV, uint64_t SrcSVOff);
     
     /// Utility function to emit atomic bitwise operations (and, or, xor).
     // It takes the bitwise instruction to expand, the associated machine basic
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index a9fc05e..3eb0e28 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -59,16 +59,14 @@
   return false;
 }
 
-/// This function returns the name of a function which has an interface
-/// like the non-standard bzero function, if such a function exists on
-/// the current subtarget and it is considered prefereable over
-/// memset with zero passed as the second argument. Otherwise it
-/// returns null.
-const char *X86Subtarget::getBZeroEntry() const {
-
+/// getBZeroEntry - This function returns the name of a function which has an
+/// interface like the non-standard bzero function, if such a function exists on
+/// the current subtarget and it is considered prefereable over memset with zero
+/// passed as the second argument. Otherwise it returns null.
+const char *X86Subtarget::getBZeroEntry(bool NoBuiltin) const {
   // Darwin 10 has a __bzero entry point for this purpose.
   if (getDarwinVers() >= 10)
-    return "__bzero";
+    return NoBuiltin ? "_bzero" : "__bzero";
 
   return 0;
 }
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index b95a2e4..98ebe89 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -184,7 +184,7 @@
   /// the current subtarget and it is considered prefereable over
   /// memset with zero passed as the second argument. Otherwise it
   /// returns null.
-  const char *getBZeroEntry() const;
+  const char *getBZeroEntry(bool NoBuiltin) const;
 };
 
 namespace X86 {