diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index ccb84ab..ca8f2db 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -596,6 +596,7 @@
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);
   // ARMv6 Thumb1 (except for CPUs that support dmb / dsb) and earlier use
   // the default expansion.
+  // FIXME: This should be checking for v6k, not just v6.
   if (Subtarget->hasDataBarrier() ||
       (Subtarget->hasV6Ops() && !Subtarget->isThumb())) {
     // membarrier needs custom lowering; the rest are legal and handled
diff --git a/lib/Target/Alpha/AlphaISelLowering.cpp b/lib/Target/Alpha/AlphaISelLowering.cpp
index 8fb6340..68ae715 100644
--- a/lib/Target/Alpha/AlphaISelLowering.cpp
+++ b/lib/Target/Alpha/AlphaISelLowering.cpp
@@ -153,6 +153,9 @@
   setOperationAction(ISD::JumpTable, MVT::i64, Custom);
   setOperationAction(ISD::JumpTable, MVT::i32, Custom);
 
+  setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
+  setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Expand);
+
   setStackPointerRegisterToSaveRestore(Alpha::R30);
 
   setJumpBufSize(272);
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 9ddf66c..3e1e009 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -178,6 +178,9 @@
   setOperationAction(ISD::MEMBARRIER,        MVT::Other, Custom);
   setOperationAction(ISD::ATOMIC_FENCE,      MVT::Other, Custom);  
 
+  setOperationAction(ISD::ATOMIC_LOAD,       MVT::i32,    Expand);  
+  setOperationAction(ISD::ATOMIC_STORE,      MVT::i32,    Expand);  
+
   setInsertFencesForAtomic(true);
 
   if (Subtarget->isSingleFloat())
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 78a75f9..f3917c4 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -365,6 +365,9 @@
     setOperationAction(ISD::BUILD_VECTOR, MVT::v4f32, Custom);
   }
 
+  setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
+  setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Expand);
+
   setBooleanContents(ZeroOrOneBooleanContent);
 
   if (TM.getSubtarget<PPCSubtarget>().isPPC64()) {