diff --git a/js/src/gc/RootMarking.cpp b/js/src/gc/RootMarking.cpp
index 87ea63c3611..54110fc9137 100644
--- a/js/src/gc/RootMarking.cpp
+++ b/js/src/gc/RootMarking.cpp
@@ -731,9 +731,13 @@ js::gc::MarkRuntime(JSTracer *trc, bool useSavedRoots)
         if (IS_GC_MARKING_TRACER(trc) && !c->isCollecting())
             continue;
 
-        if (IS_GC_MARKING_TRACER(trc) && (c->activeAnalysis || c->isPreservingCode())) {
-            gcstats::AutoPhase ap(rt->gcStats, gcstats::PHASE_MARK_TYPES);
-            c->markTypes(trc);
+        if (IS_GC_MARKING_TRACER(trc)) {
+            if ((c->activeAnalysis || c->isPreservingCode())) {
+                gcstats::AutoPhase ap(rt->gcStats, gcstats::PHASE_MARK_TYPES);
+                c->markTypes(trc);
+            } else {
+                c->gcTypesMarked = false;
+            }
         }
 
         /* During a GC, these are treated as weak pointers. */
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index c1efe24bd37..356db90ea5a 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -808,7 +808,6 @@ JSRuntime::JSRuntime(JSUseHelperThreads useHelperThreads)
     gcSweepPhase(0),
     gcSweepCompartment(NULL),
     gcSweepKindIndex(0),
-    gcAbortSweepAfterCurrentGroup(false),
     gcArenasAllocatedDuringSweep(NULL),
 #ifdef DEBUG
     gcMarkingValidator(NULL),
diff --git a/js/src/jscntxt.h b/js/src/jscntxt.h
index c0e592ef514..e78324bf3d8 100644
--- a/js/src/jscntxt.h
+++ b/js/src/jscntxt.h
@@ -730,7 +730,6 @@ struct JSRuntime : js::RuntimeFriendFields
     int                 gcSweepPhase;
     JSCompartment       *gcSweepCompartment;
     int                 gcSweepKindIndex;
-    bool                gcAbortSweepAfterCurrentGroup;
 
     /*
      * List head of arenas allocated during the sweep phase.
diff --git a/js/src/jscompartment.cpp b/js/src/jscompartment.cpp
index 449886f98c5..756b11463e9 100644
--- a/js/src/jscompartment.cpp
+++ b/js/src/jscompartment.cpp
@@ -573,6 +573,8 @@ JSCompartment::markTypes(JSTracer *trc)
         MarkTypeObjectRoot(trc, &type, "mark_types_scan");
         JS_ASSERT(type == i.get<types::TypeObject>());
     }
+
+    gcTypesMarked = true;
 }
 
 void
diff --git a/js/src/jscompartment.h b/js/src/jscompartment.h
index a0a21b5084e..39f75b983e7 100644
--- a/js/src/jscompartment.h
+++ b/js/src/jscompartment.h
@@ -379,6 +379,12 @@ struct JSCompartment : private JS::shadow::Compartment, public js::gc::GraphNode
     /* This compartment's gray roots. */
     js::Vector<js::GrayRoot, 0, js::SystemAllocPolicy> gcGrayRoots;
 
+    /*
+     * Whether type objects have been marked by markTypes().  This is used to
+     * determine whether they need to be swept.
+     */
+    bool                         gcTypesMarked;
+
   private:
     /*
      * Malloc counter to measure memory pressure for GC scheduling. It runs from
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index 1e8e5a266f2..490b6978f4a 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -3098,9 +3098,6 @@ FindCompartmentGroups(JSRuntime *rt)
     rt->gcCompartmentGroupIndex = 0;
 }
 
-static void
-ResetGrayList(JSCompartment* comp);
-
 static void
 GetNextCompartmentGroup(JSRuntime *rt)
 {
@@ -3109,26 +3106,6 @@ GetNextCompartmentGroup(JSRuntime *rt)
 
     if (!rt->gcIsIncremental)
         ComponentFinder<JSCompartment>::mergeCompartmentGroups(rt->gcCurrentCompartmentGroup);
-
-    if (rt->gcAbortSweepAfterCurrentGroup) {
-        /*
-         * Iterate over all compartments that haven't been swept yet and reset
-         * their state such that ther are no longer being collected.
-         */
-        JS_ASSERT(!rt->gcIsIncremental);
-        for (GCCompartmentGroupIter c(rt); !c.done(); c.next()) {
-            JS_ASSERT(!c->gcNextGraphComponent);
-            JS_ASSERT(c->isGCMarking());
-            c->setNeedsBarrier(false, JSCompartment::UpdateIon);
-            c->setGCState(JSCompartment::NoGC);
-            ArrayBufferObject::resetArrayBufferList(c);
-            ResetGrayList(c);
-            c->gcGrayRoots.clearAndFree();
-        }
-
-        rt->gcAbortSweepAfterCurrentGroup = false;
-        rt->gcCurrentCompartmentGroup = NULL;
-    }
 }
 
 /*
@@ -3319,15 +3296,6 @@ RemoveFromGrayList(RawObject wrapper)
     return false;
 }
 
-static void
-ResetGrayList(JSCompartment* comp)
-{
-    RawObject src = comp->gcIncomingGrayPointers;
-    while (src)
-        src = NextIncomingCrossCompartmentPointer(src, true);
-    comp->gcIncomingGrayPointers = NULL;
-}
-
 void
 js::NotifyGCNukeWrapper(RawObject o)
 {
@@ -3533,8 +3501,6 @@ BeginSweepPhase(JSRuntime *rt)
      * fail, rather than nest badly and leave the unmarked newborn to be swept.
      */
 
-    JS_ASSERT(!rt->gcAbortSweepAfterCurrentGroup);
-
     ComputeNonIncrementalMarkingForValidation(rt);
 
     gcstats::AutoPhase ap(rt->gcStats, gcstats::PHASE_SWEEP);
@@ -3631,9 +3597,8 @@ EndSweepPhase(JSRuntime *rt, JSGCInvocationKind gckind, bool lastGC)
 
     /*
      * If we found any black->gray edges during marking, we completely clear the
-     * mark bits of all uncollected compartments, or if a reset has occured,
-     * compartments that will no longer be collected. This is safe, although it
-     * may prevent the cycle collector from collecting some dead objects.
+     * mark bits of all uncollected compartments. This is safe, although it may
+     * prevent the cycle collector from collecting some dead objects.
      */
     if (rt->gcFoundBlackGrayEdges) {
         for (CompartmentsIter c(rt); !c.done(); c.next()) {
@@ -3841,11 +3806,11 @@ ResetIncrementalGC(JSRuntime *rt, const char *reason)
         rt->gcMarker.stop();
 
         for (GCCompartmentsIter c(rt); !c.done(); c.next()) {
-            JS_ASSERT(c->isGCMarking());
-            c->setNeedsBarrier(false, JSCompartment::UpdateIon);
-            c->setGCState(JSCompartment::NoGC);
-            ArrayBufferObject::resetArrayBufferList(c);
-            ResetGrayList(c);
+            if (c->isGCMarking()) {
+                c->setNeedsBarrier(false, JSCompartment::UpdateIon);
+                c->setGCState(JSCompartment::NoGC);
+                ArrayBufferObject::resetArrayBufferList(c);
+            }
         }
 
         rt->gcIncrementalState = NO_INCREMENTAL;
@@ -3856,13 +3821,21 @@ ResetIncrementalGC(JSRuntime *rt, const char *reason)
       }
 
       case SWEEP:
-        rt->gcMarker.reset();
-
-        for (CompartmentsIter c(rt); !c.done(); c.next())
+        for (CompartmentsIter c(rt); !c.done(); c.next()) {
             c->scheduledForDestruction = false;
 
-        /* Finish sweeping the current compartment group, then abort. */
-        rt->gcAbortSweepAfterCurrentGroup = true;
+            if (c->isGCMarking() && c->activeAnalysis && !c->gcTypesMarked) {
+                AutoCopyFreeListToArenas copy(rt);
+                gcstats::AutoPhase ap1(rt->gcStats, gcstats::PHASE_SWEEP);
+                gcstats::AutoPhase ap2(rt->gcStats, gcstats::PHASE_SWEEP_MARK);
+                gcstats::AutoPhase ap3(rt->gcStats, gcstats::PHASE_SWEEP_MARK_TYPES);
+                rt->gcIncrementalState = MARK_ROOTS;
+                c->markTypes(&rt->gcMarker);
+                rt->gcIncrementalState = SWEEP;
+            }
+        }
+
+        /* If we had started sweeping then sweep to completion here. */
         IncrementalCollectSlice(rt, SliceBudget::Unlimited, gcreason::RESET, GC_NORMAL);
 
         {