diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 87f4aa46cda..6cfb55077b9 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1847,13 +1847,12 @@ static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
 
 static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
                                    AsmPrinter &AP) {
-  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
-    uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
+  const TargetData *TD = AP.TM.getTargetData();
+  uint64_t Size = TD->getTypeAllocSize(CV->getType());
+  if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
     return AP.OutStreamer.EmitZeros(Size, AddrSpace);
-  }
 
   if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
-    unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
     switch (Size) {
     case 1:
     case 2:
@@ -1874,7 +1873,6 @@ static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
     return EmitGlobalConstantFP(CFP, AddrSpace, AP);
 
   if (isa<ConstantPointerNull>(CV)) {
-    unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
     AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
     return;
   }
@@ -1888,20 +1886,28 @@ static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
   if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
     return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
 
-  // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
-  // vectors).
-  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV))
+  if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
+    // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
+    // vectors).
     if (CE->getOpcode() == Instruction::BitCast)
       return EmitGlobalConstantImpl(CE->getOperand(0), AddrSpace, AP);
+
+    if (Size > 8) {
+      // If the constant expression's size is greater than 64-bits, then we have
+      // to emit the value in chunks. Try to constant fold the value and emit it
+      // that way.
+      Constant *New = ConstantFoldConstantExpression(CE, TD);
+      if (New && New != CE)
+        return EmitGlobalConstantImpl(New, AddrSpace, AP);
+    }
+  }
   
   if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
     return EmitGlobalConstantVector(V, AddrSpace, AP);
     
   // Otherwise, it must be a ConstantExpr.  Lower it to an MCExpr, then emit it
   // thread the streamer with EmitValue.
-  AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
-                         AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
-                           AddrSpace);
+  AP.OutStreamer.EmitValue(LowerConstant(CV, AP), Size, AddrSpace);
 }
 
 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
diff --git a/test/CodeGen/X86/2012-03-20-LargeConstantExpr.ll b/test/CodeGen/X86/2012-03-20-LargeConstantExpr.ll
new file mode 100644
index 00000000000..d24647e0644
--- /dev/null
+++ b/test/CodeGen/X86/2012-03-20-LargeConstantExpr.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+; <rdar://problem/11070338>
+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-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+; CHECK:      _.memset_pattern:
+; CHECK-NEXT: .quad   4575657222473777152
+; CHECK-NEXT: .quad   4575657222473777152
+
+@.memset_pattern = internal unnamed_addr constant i128 or (i128 zext (i64 bitcast (<2 x float> <float 1.000000e+00, float 1.000000e+00> to i64) to i128), i128 shl (i128 zext (i64 bitcast (<2 x float> <float 1.000000e+00, float 1.000000e+00> to i64) to i128), i128 64)), align 16
+
+define void @foo(i8* %a, i64 %b) {
+  call void @memset_pattern16(i8* %a, i8* bitcast (i128* @.memset_pattern to i8*), i64 %b)
+  ret void
+}
+
+declare void @memset_pattern16(i8*, i8*, i64)