fix #17430: int64类型的attr训练非预期 (#18264)

* fix int64_t

* update fill constant op unittest

* add empty line

paddle/fluid/framework/attribute.h

@@ -133,6 +133,32 @@ struct ExtractAttribute<std::vector<int64_t>> {
   const std::string& attr_name_;
 };
 
+template <>
+struct ExtractAttribute<float> {
+  explicit ExtractAttribute(const std::string& attr_name)
+      : attr_name_(attr_name) {}
+
+  float* operator()(Attribute& attr) const {
+    if (attr.type() == typeid(int)) {  // NOLINT
+      int val = boost::get<int>(attr);
+      attr = static_cast<float>(val);
+    } else if (attr.type() == typeid(int64_t)) {  // NOLINT
+      int64_t val = boost::get<int64_t>(attr);
+      attr = static_cast<float>(val);
+    }
+    float* attr_value = nullptr;
+    try {
+      attr_value = &boost::get<float>(attr);
+    } catch (boost::bad_get& bad_get) {
+      PADDLE_THROW("Cannot get attribute %s by type float, its type is %s",
+                   attr_name_, paddle::platform::demangle(attr.type().name()));
+    }
+    return attr_value;
+  }
+
+  const std::string& attr_name_;
+};
+
 template <typename T>
 inline proto::AttrType AttrTypeID() {
   Attribute tmp = T();

paddle/fluid/pybind/pybind_boost_headers.h

@@ -77,6 +77,15 @@ struct paddle_variant_caster<V<Ts...>> {
         }
       }
 
+      if (std::is_same<T, float>::value) {
+        auto caster_int64 = make_caster<int64_t>();
+        if (caster_int64.load(src, convert)) {
+          VLOG(4) << "this value are float and int64 satisfy simula.";
+          value = cast_op<int64_t>(caster_int64);
+          return true;
+        }
+      }
+
       value = cast_op<T>(caster);
       return true;
     }

python/paddle/fluid/tests/unittests/test_fill_constant_op.py

@@ -50,6 +50,34 @@ class TestFillConstantOp2(OpTest):
         self.check_output()
 
 
+class TestFillConstantOp3(OpTest):
+    def setUp(self):
+        '''Test fill_constant op with specified int64 value
+        '''
+        self.op_type = "fill_constant"
+
+        self.inputs = {}
+        self.attrs = {'shape': [123, 92], 'value': 10000000000}
+        self.outputs = {'Out': np.full((123, 92), 10000000000)}
+
+    def test_check_output(self):
+        self.check_output()
+
+
+class TestFillConstantOp4(OpTest):
+    def setUp(self):
+        '''Test fill_constant op with specified int value
+        '''
+        self.op_type = "fill_constant"
+
+        self.inputs = {}
+        self.attrs = {'shape': [123, 92], 'value': 3}
+        self.outputs = {'Out': np.full((123, 92), 3)}
+
+    def test_check_output(self):
+        self.check_output()
+
+
 class TestFillConstantOpWithSelectedRows(OpTest):
     def check_with_place(self, place):
         scope = core.Scope()