[OPENCL] Fix 32bit pointer size in OpenCL runtime (#809)

src/runtime/opencl/opencl_module.cc

@@ -254,9 +254,14 @@ PackedFunc OpenCLModuleNode::GetFunction(
   for (size_t i = 0; i < info.arg_types.size(); ++i) {
     TVMType t = info.arg_types[i];
     CHECK_EQ(t.lanes, 1U);
-    uint32_t bits = t.bits;
-    CHECK_EQ(bits % 8, 0U);
-    arg_size[i] = bits / 8;
+    if (t.code == kHandle) {
+      // specially store pointer type size in OpenCL driver
+      arg_size[i] = sizeof(void*);
+    } else {
+      uint32_t bits = t.bits;
+      CHECK_EQ(bits % 8, 0U);
+      arg_size[i] = bits / 8;
+    }
   }
   // initialize the wrapped func.
   f.Init(this, sptr_to_self, kid_map_.at(name),