diff --git a/runtime/observatory/tests/service/service_kernel.status b/runtime/observatory/tests/service/service_kernel.status
index 7012181..cea771c 100644
--- a/runtime/observatory/tests/service/service_kernel.status
+++ b/runtime/observatory/tests/service/service_kernel.status
@@ -77,7 +77,6 @@
 [ $arch == simdbc64 && $compiler == dartk ]
 eval_test: RuntimeError, Timeout # Issue #34736
 evaluate_in_frame_rpc_test: RuntimeError, Timeout # Issue #34736
-get_cpu_profile_timeline_rpc_test: Pass, RuntimeError # http://dartbug.com/31794
 
 [ $arch == simdbc64 && $compiler == dartk && $mode == debug ]
 eval_test: Pass, Slow
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index 7eed0f3..ed05a74 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -791,7 +791,8 @@
         return;
       }
 
-      if ((pc + 1) < pc) {
+      const uword pc_value = reinterpret_cast<uword>(pc);
+      if ((pc_value + 1) < pc_value) {
         // It is not uncommon to encounter an invalid pc as we
         // traverse a stack frame.  Most of these we can tolerate.  If
         // the pc is so large that adding one to it will cause an
@@ -805,7 +806,7 @@
       // Move the lower bound up.
       lower_bound_ = reinterpret_cast<uword>(fp);
 
-      if (!Append(reinterpret_cast<uword>(pc), reinterpret_cast<uword>(fp))) {
+      if (!Append(pc_value, reinterpret_cast<uword>(fp))) {
         return;
       }
     }
diff --git a/runtime/vm/profiler_service.cc b/runtime/vm/profiler_service.cc
index a92e31e..44bd3c5 100644
--- a/runtime/vm/profiler_service.cc
+++ b/runtime/vm/profiler_service.cc
@@ -2231,6 +2231,7 @@
     }
 
     ASSERT(pc >= native_start);
+    ASSERT(pc < (pc + 1));  // Should not overflow.
     profile_code = new ProfileCode(ProfileCode::kNativeCode, native_start,
                                    pc + 1, 0, null_code_);
     if (native_name != NULL) {