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paddle/framework/operator.h

@@ -451,8 +451,8 @@ class OperatorWithKernel : public OperatorBase {
     size_t operator()(const OpKernelKey& key) const {
       int place = key.place_.which();
       int data_type = static_cast<int>(key.data_type_);
-      // NOTE: Number of places limit to 16.
-      int pre_hash = data_type << 4 | (place & 0x0F);
+      int pre_hash = data_type << NUM_PLACE_TYPE_LIMIT_IN_BIT |
+                     (place & ((1 << NUM_PLACE_TYPE_LIMIT_IN_BIT) - 1));
       return hash_(pre_hash);
     }
   };

paddle/platform/place.h

@@ -15,6 +15,7 @@ limitations under the License. */
 #pragma once
 
 #include <iostream>
+
 #include "paddle/platform/variant.h"
 
 namespace paddle {
@@ -46,8 +47,18 @@ struct IsGPUPlace : public boost::static_visitor<bool> {
   bool operator()(const GPUPlace &gpu) const { return true; }
 };
 
+// Define the max number of Place in bit length. i.e., the max number of places
+// should be less equal than 2^(NUM_PLACE_TYPE_LIMIT_IN_BIT)
+#define NUM_PLACE_TYPE_LIMIT_IN_BIT 4
+
 typedef boost::variant<GPUPlace, CPUPlace> Place;
 
+// static check number of place types is less equal than
+// 2^(NUM_PLACE_TYPE_LIMIT_IN_BIT)
+BOOST_MPL_ASSERT((boost::mpl::less_equal<
+                  Place::types::size,
+                  boost::mpl::long_<1 << NUM_PLACE_TYPE_LIMIT_IN_BIT>>));
+
 void set_place(const Place &);
 const Place &get_place();
 

paddle/platform/variant.h

@@ -29,4 +29,6 @@
 #endif
 #endif
 
+#include <boost/mpl/comparison.hpp>
+#include <boost/mpl/less_equal.hpp>
 #include <boost/variant.hpp>