diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9e02c7be710..c852c061d06 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -25,6 +25,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/DataLayout.h"
 #include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -7748,8 +7749,10 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode* St) {
         LastLegalVectorType = i + 1;
     }
 
-    // We only use vectors if the constant is known to be zero.
-    if (NonZero)
+    // We only use vectors if the constant is known to be zero and the
+    // function is not marked with the noimplicitfloat attribute.
+    if (NonZero || (DAG.getMachineFunction().getFunction()->getFnAttributes().
+                    hasAttribute(Attribute::NoImplicitFloat)))
       LastLegalVectorType = 0;
 
     // Check if we found a legal integer type to store.
diff --git a/test/CodeGen/X86/2012-12-19-NoImplicitFloat.ll b/test/CodeGen/X86/2012-12-19-NoImplicitFloat.ll
new file mode 100644
index 00000000000..30256652067
--- /dev/null
+++ b/test/CodeGen/X86/2012-12-19-NoImplicitFloat.ll
@@ -0,0 +1,17 @@
+; RUN: llc -mtriple=x86_64-apple-macosx10.8.0 -mcpu=core2 < %s | FileCheck %s
+; Test that we do not introduce vector operations with noimplicitfloat.
+; rdar://12879313
+
+%struct1 = type { i32*, i32* }
+
+define void @test() nounwind noimplicitfloat {
+entry:
+; CHECK-NOT: xmm
+; CHECK: ret
+  %0 = load %struct1** undef, align 8
+  %1 = getelementptr inbounds %struct1* %0, i64 0, i32 0
+  store i32* null, i32** %1, align 8
+  %2 = getelementptr inbounds %struct1* %0, i64 0, i32 1
+  store i32* null, i32** %2, align 8
+  ret void
+}