From 211940ebb910fb2c97e2859009ddf7ba559ad167 Mon Sep 17 00:00:00 2001
From: Jack Zhou <zhoushunjie@baidu.com>
Date: Wed, 10 Nov 2021 12:56:47 +0800
Subject: [PATCH] Fix rnn grad bug in cpu when dropout is zero (#37080)

* fix rnn grad bug when num_layers is set 2 and dropout_prob is set 0

* add more test for rnn
---
 paddle/fluid/operators/rnn_op.h               |  3 ++
 .../fluid/tests/unittests/test_rnn_op.py      | 30 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/paddle/fluid/operators/rnn_op.h b/paddle/fluid/operators/rnn_op.h
index ab64e50d450..5e19be5e4cf 100644
--- a/paddle/fluid/operators/rnn_op.h
+++ b/paddle/fluid/operators/rnn_op.h
@@ -965,6 +965,9 @@ class RNNCPUKernel : public framework::OpKernel<T> {
     }
     dropout_mask->mutable_data<uint8_t>(output->dims(), ctx.GetPlace());
 
+    auto& dev_ctx = ctx.template device_context<platform::CPUDeviceContext>();
+    math::SetConstant<platform::CPUDeviceContext, uint8_t> ones;
+    ones(dev_ctx, dropout_mask, static_cast<uint8_t>(1));
     // init the output and allocate the memory
     output->mutable_data<T>(ctx.GetPlace());
     int gate_num = 4;
diff --git a/python/paddle/fluid/tests/unittests/test_rnn_op.py b/python/paddle/fluid/tests/unittests/test_rnn_op.py
index 763ec3e7038..79e33166bb6 100644
--- a/python/paddle/fluid/tests/unittests/test_rnn_op.py
+++ b/python/paddle/fluid/tests/unittests/test_rnn_op.py
@@ -168,5 +168,35 @@ class TestRNNOp4(TestRNNOp):
         self.is_bidirec = True
 
 
+class TestRNNOp5(TestRNNOp):
+    def set_attrs(self):
+        self.num_layers = 2
+
+
+class TestRNNOp6(TestRNNOp):
+    def set_attrs(self):
+        self.num_layers = 2
+        self.is_bidirec = True
+
+
+class TestRNNOp7(TestRNNOp):
+    def set_attrs(self):
+        self.num_layers = 2
+        self.is_bidirec = True
+        self.is_test = True
+
+
+class TestRNNOp8(TestRNNOp):
+    def set_attrs(self):
+        self.num_layers = 2
+        self.is_bidirec = True
+        self.sequence_length = None
+
+
+class TestRNNOp9(TestRNNOp):
+    def set_attrs(self):
+        self.num_layers = 3
+
+
 if __name__ == '__main__':
     unittest.main()
-- 
GitLab