diff --git a/python/tvm/autotvm/tuner/tuner.py b/python/tvm/autotvm/tuner/tuner.py
index 76d088f4c..7ed4ff02a 100644
--- a/python/tvm/autotvm/tuner/tuner.py
+++ b/python/tvm/autotvm/tuner/tuner.py
@@ -122,7 +122,7 @@ class Tuner(object):
             configs = self.next_batch(min(n_parallel, n_trial - i))
 
             inputs = [MeasureInput(self.task.target, self.task, config) for config in configs]
-            results = measure_batch(inputs)
+            results = self.parse_configs(self.task, configs) if hasattr(self, 'parse_configs') else measure_batch(inputs)
 
             # keep best config
             for k, (inp, res) in enumerate(zip(inputs, results)):
diff --git a/src/codegen/codegen_c.cc b/src/codegen/codegen_c.cc
index eab542dd3..2f1a11303 100644
--- a/src/codegen/codegen_c.cc
+++ b/src/codegen/codegen_c.cc
@@ -808,6 +808,7 @@ void CodeGenC::VisitStmt_(const AttrStmt* op) {
     IterVar iv = Downcast<IterVar>(op->node);
     if (iv->thread_tag.length() != 0) {
       if (!var_idmap_.count(iv->var.get())) {
+        this->currentOp = op;
         BindThreadIndex(iv);
       }
     }
diff --git a/src/codegen/codegen_c.h b/src/codegen/codegen_c.h
index 8701cda1e..7d3d56ddc 100644
--- a/src/codegen/codegen_c.h
+++ b/src/codegen/codegen_c.h
@@ -174,6 +174,8 @@ class CodeGenC :
   // Get a cast type from to
   virtual std::string CastFromTo(std::string value, Type from, Type target);
 
+  const AttrStmt* currentOp;
+
  protected:
   // Print reference to struct location
   std::string GetStructRef(
diff --git a/src/codegen/codegen_cuda.cc b/src/codegen/codegen_cuda.cc
index 6656fa077..a4f0f962d 100644
--- a/src/codegen/codegen_cuda.cc
+++ b/src/codegen/codegen_cuda.cc
@@ -106,6 +106,9 @@ void CodeGenCUDA::BindThreadIndex(const IterVar& iv) {
   CHECK(!var_idmap_.count(iv->var.get()));
   var_idmap_[iv->var.get()] =
       CastFromTo(iv->thread_tag, UInt(32), iv->var.type());
+  int nthread = static_cast<int>(this->currentOp->value.as<IntImm>()->value);
+  if (iv->thread_tag.find("threadIdx.") == 0 || iv->thread_tag.find("blockIdx.") == 0)
+    this->stream << "  // [thread_extent] " << iv->thread_tag << " = " << nthread << "\n";
 }
 
 void CodeGenCUDA::PrintType(Type t, std::ostream& os) {  // NOLINT(*)
diff --git a/src/codegen/opt/build_cuda_on.cc b/src/codegen/opt/build_cuda_on.cc
index 1992ac5d9..9b0ff4cd9 100644
--- a/src/codegen/opt/build_cuda_on.cc
+++ b/src/codegen/opt/build_cuda_on.cc
@@ -137,6 +137,9 @@ runtime::Module BuildCUDA(Array<LoweredFunc> funcs) {
     cg.AddFunction(f);
   }
   std::string code = cg.Finish();
+  const auto* backendproc = Registry::Get("tvm_callback_backend_proc");
+  if (backendproc)
+    return CUDAModuleCreate((*backendproc)(code).operator std::string(), "cubin", ExtractFuncInfo(funcs), code);
 
   if (const auto* f = Registry::Get("tvm_callback_cuda_postproc")) {
     code = (*f)(code).operator std::string();
diff --git a/src/lang/expr_operator.cc b/src/lang/expr_operator.cc
index 220d4378c..cc435d138 100644
--- a/src/lang/expr_operator.cc
+++ b/src/lang/expr_operator.cc
@@ -208,11 +208,11 @@ Expr operator%(Expr a, Expr b) {
 
 // TODO(tqchen): switch to floordiv
 Expr indexdiv(Expr a, Expr b) {
-  return floordiv(a, b);
+  return truncdiv(a, b);
 }
 
 Expr indexmod(Expr a, Expr b) {
-  return floormod(a, b);
+  return truncmod(a, b);
 }
 
 Expr floordiv(Expr a, Expr b) {