enhance memory optimization transpiler to support user defined skip_opt_set (#11372)

* fix mac build error

* enhance memory optimize transpiler to let users set to some skip opt set of variables

python/paddle/fluid/transpiler/memory_optimization_transpiler.py

@@ -157,9 +157,11 @@ class ControlFlowGraph(object):
             if op.type() == "fill_constant" and op.attr("force_cpu") == True:
                 self._skip_opt.update(op.output_arg_names())
 
-    def release_memory(self):
+    def release_memory(self, skip_opt_set=None):
         self._dataflow_analyze()
         self._update_skip_opt_set()
+        if skip_opt_set:
+            self._skip_opt.update(skip_opt_set)
         fwd_id = 0
         bwd_id = 0
         for i in range(self.op_size):
@@ -183,7 +185,7 @@ class ControlFlowGraph(object):
                 else:
                     bwd_id += 1
 
-    def memory_optimize(self, level=0):
+    def memory_optimize(self, skip_opt_set=None, level=0):
         def compare_shape(x_shape, cache_shape, opt_level):
             if opt_level == 0:
                 return x_shape == cache_shape
@@ -200,6 +202,9 @@ class ControlFlowGraph(object):
 
         self._dataflow_analyze()
         self._update_skip_opt_set()
+        # update skip set to meet users' demand
+        if skip_opt_set:
+            self._skip_opt.update(skip_opt_set)
         self.pool = []
         for i in range(self.op_size):
             op = self._ops[i]
@@ -358,7 +363,7 @@ def _get_cfgs(input_program):
     return cfgs
 
 
-def memory_optimize(input_program, print_log=False, level=0):
+def memory_optimize(input_program, skip_opt_set=None, print_log=False, level=0):
     """Optimize memory by reusing var memory.
 
       Note: it doesn't not support subblock nested in subblock.
@@ -374,10 +379,10 @@ def memory_optimize(input_program, print_log=False, level=0):
     PRINT_LOG = print_log
     cfgs = _get_cfgs(input_program)
     for cfg in cfgs:
-        cfg.memory_optimize(level)
+        cfg.memory_optimize(skip_opt_set=skip_opt_set, level=level)
 
 
-def release_memory(input_program):
+def release_memory(input_program, skip_opt_set=None):
     cfgs = _get_cfgs(input_program)
     for cfg in cfgs:
-        cfg.release_memory()
+        cfg.release_memory(skip_opt_set=skip_opt_set)