Index: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -2925,12 +2925,12 @@
     case ISD::ZERO_EXTEND:
       LHS = DAG.getNode(ISD::AssertZext, dl, OuterType, Res,
                         DAG.getValueType(AtomicType));
-      RHS = DAG.getNode(ISD::ZERO_EXTEND, dl, OuterType, Node->getOperand(2));
+      RHS = DAG.getZeroExtendInReg(Node->getOperand(2), dl, AtomicType);
       ExtRes = LHS;
       break;
     case ISD::ANY_EXTEND:
       LHS = DAG.getZeroExtendInReg(Res, dl, AtomicType);
-      RHS = DAG.getNode(ISD::ZERO_EXTEND, dl, OuterType, Node->getOperand(2));
+      RHS = DAG.getZeroExtendInReg(Node->getOperand(2), dl, AtomicType);
       break;
     default:
       llvm_unreachable("Invalid atomic op extension");
Index: test/CodeGen/ARM/atomic-cmpxchg.ll
===================================================================
--- test/CodeGen/ARM/atomic-cmpxchg.ll
+++ test/CodeGen/ARM/atomic-cmpxchg.ll
@@ -46,9 +46,10 @@
 ; CHECK-ARMV6-NEXT: b [[TRY]]
 
 ; CHECK-THUMBV6-LABEL: test_cmpxchg_res_i8:
-; CHECK-THUMBV6:       mov [[EXPECTED:r[0-9]+]], r1
+; CHECK-THUMBV6:       mov [[TMP:r[0-9]+]], r1
 ; CHECK-THUMBV6-NEXT:  bl __sync_val_compare_and_swap_1
 ; CHECK-THUMBV6-NEXT:  mov [[RES:r[0-9]+]], r0
+; CHECK-THUMBV6-NEXT:  uxtb [[EXPECTED:r[0-9]+]], [[TMP]]
 ; CHECK-THUMBV6-NEXT:  movs r0, #1
 ; CHECK-THUMBV6-NEXT:  movs [[ZERO:r[0-9]+]], #0
 ; CHECK-THUMBV6-NEXT:  cmp [[RES]], [[EXPECTED]]
Index: test/CodeGen/ARM/cmpxchg-O0.ll
===================================================================
--- test/CodeGen/ARM/cmpxchg-O0.ll
+++ test/CodeGen/ARM/cmpxchg-O0.ll
@@ -17,7 +17,8 @@
 ; CHECK:     cmp{{(\.w)?}} [[STATUS]], #0
 ; CHECK:     bne [[RETRY]]
 ; CHECK: [[DONE]]:
-; CHECK:     cmp{{(\.w)?}} [[OLD]], [[DESIRED]]
+; CHECK:     uxtb [[TMP:r[0-9]+]], [[DESIRED]]
+; CHECK:     cmp{{(\.w)?}} [[OLD]], [[TMP]]
 ; CHECK:     {{moveq|movweq}} {{r[0-9]+}}, #1
 ; CHECK:     dmb ish
   %res = cmpxchg i8* %addr, i8 %desired, i8 %new seq_cst monotonic
@@ -36,7 +37,8 @@
 ; CHECK:     cmp{{(\.w)?}} [[STATUS]], #0
 ; CHECK:     bne [[RETRY]]
 ; CHECK: [[DONE]]:
-; CHECK:     cmp{{(\.w)?}} [[OLD]], [[DESIRED]]
+; CHECK:     uxth [[TMP:r[0-9]+]], [[DESIRED]]
+; CHECK:     cmp{{(\.w)?}} [[OLD]], [[TMP]]
 ; CHECK:     {{moveq|movweq}} {{r[0-9]+}}, #1
 ; CHECK:     dmb ish
   %res = cmpxchg i16* %addr, i16 %desired, i16 %new seq_cst monotonic
Index: test/CodeGen/SystemZ/cmpxchg-05.ll
===================================================================
--- test/CodeGen/SystemZ/cmpxchg-05.ll
+++ test/CodeGen/SystemZ/cmpxchg-05.ll
@@ -79,3 +79,17 @@
   %xres = sext i1 %res to i8
   ret i8 %xres
 }
+
+; Verify that computing the comparison result extends the input value
+; CHECK-LABEL: f7
+; CHECK: llc [[VAL:%r[0-9]+]], 0(%r3)
+; CHECK: llcr [[REG:%r[0-9]+]], [[RES:%r[0-9]+]]
+; CHECK: cr [[REG]], [[VAL]]
+define zeroext i8 @f7(i8* nocapture, i8 *, i8 zeroext) {
+  %val = load i8, i8 *%1
+  %cx = cmpxchg i8* %0, i8 %val, i8 %2 seq_cst seq_cst
+  %res = extractvalue { i8, i1 } %cx, 1
+  %xres = sext i1 %res to i8
+  ret i8 %xres
+}
+