diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 390cd92cd6f..79c13913e9a 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -946,6 +946,10 @@ bool ARMFastISel::ARMEmitLoad(EVT VT, unsigned &ResultReg, Address &Addr) {
 }
 
 bool ARMFastISel::SelectLoad(const Instruction *I) {
+  // Atomic loads need special handling.
+  if (cast<LoadInst>(I)->isAtomic())
+    return false;
+
   // Verify we have a legal type before going any further.
   MVT VT;
   if (!isLoadTypeLegal(I->getType(), VT))
@@ -1008,6 +1012,10 @@ bool ARMFastISel::SelectStore(const Instruction *I) {
   Value *Op0 = I->getOperand(0);
   unsigned SrcReg = 0;
 
+  // Atomic stores need special handling.
+  if (cast<StoreInst>(I)->isAtomic())
+    return false;
+
   // Verify we have a legal type before going any further.
   MVT VT;
   if (!isLoadTypeLegal(I->getOperand(0)->getType(), VT))
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index f5db6d28a24..452b215071f 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -658,6 +658,10 @@ bool X86FastISel::X86SelectCallAddress(const Value *V, X86AddressMode &AM) {
 
 /// X86SelectStore - Select and emit code to implement store instructions.
 bool X86FastISel::X86SelectStore(const Instruction *I) {
+  // Atomic stores need special handling.
+  if (cast<StoreInst>(I)->isAtomic())
+    return false;
+
   MVT VT;
   if (!isTypeLegal(I->getOperand(0)->getType(), VT, /*AllowI1=*/true))
     return false;
@@ -780,6 +784,10 @@ bool X86FastISel::X86SelectRet(const Instruction *I) {
 /// X86SelectLoad - Select and emit code to implement load instructions.
 ///
 bool X86FastISel::X86SelectLoad(const Instruction *I)  {
+  // Atomic loads need special handling.
+  if (cast<LoadInst>(I)->isAtomic())
+    return false;
+
   MVT VT;
   if (!isTypeLegal(I->getType(), VT, /*AllowI1=*/true))
     return false;
diff --git a/test/CodeGen/ARM/atomic-load-store.ll b/test/CodeGen/ARM/atomic-load-store.ll
index 1625e53c91a..81c828485e6 100644
--- a/test/CodeGen/ARM/atomic-load-store.ll
+++ b/test/CodeGen/ARM/atomic-load-store.ll
@@ -1,4 +1,5 @@
 ; RUN: llc < %s -mtriple=armv7-apple-ios | FileCheck %s -check-prefix=ARM
+; RUN: llc < %s -mtriple=armv7-apple-ios -O0 | FileCheck %s -check-prefix=ARM
 ; RUN: llc < %s -mtriple=thumbv7-apple-ios | FileCheck %s -check-prefix=THUMBTWO
 ; RUN: llc < %s -mtriple=thumbv6-apple-ios | FileCheck %s -check-prefix=THUMBONE
 
diff --git a/test/CodeGen/X86/atomic-load-store.ll b/test/CodeGen/X86/atomic-load-store.ll
index 7738ace4ff1..5430a509a8d 100644
--- a/test/CodeGen/X86/atomic-load-store.ll
+++ b/test/CodeGen/X86/atomic-load-store.ll
@@ -1,4 +1,5 @@
 ; RUN: llc < %s -mtriple=x86_64-apple-macosx10.7.0 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-apple-macosx10.7.0 -O0 | FileCheck %s
 
 define void @test1(i32* %ptr, i32 %val1) {
 ; CHECK: test1