rename the LayerNorm operator and add it to the replacement map (#40318)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40318

rename layernom fakefp16 to the right naming convention
add it to the map of replacement ops

this can be done even if the operator is not complete because we are blacklisting anyways

Test Plan: net_runner and inspected the log that replacement happened

Reviewed By: venkatacrc

Differential Revision: D22145900

fbshipit-source-id: f19794ec05234b877f7697ed8b05dd8f46606c47
diff --git a/caffe2/contrib/fakelowp/layernorm_fp16_fake_op.cc b/caffe2/contrib/fakelowp/layernorm_fp16_fake_op.cc
index 6eb5873..cfc3685 100644
--- a/caffe2/contrib/fakelowp/layernorm_fp16_fake_op.cc
+++ b/caffe2/contrib/fakelowp/layernorm_fp16_fake_op.cc
@@ -136,7 +136,7 @@
   }
 }
 
-REGISTER_CPU_OPERATOR(LayerNormFakeFP16, LayerNormFakeFp16Op<CPUContext>);
-OPERATOR_SCHEMA(LayerNormFakeFP16).NumInputs({1, 3}).NumOutputs(3);
+REGISTER_CPU_OPERATOR(LayerNormFakeFP16NNPI, LayerNormFakeFp16Op<CPUContext>);
+OPERATOR_SCHEMA(LayerNormFakeFP16NNPI).NumInputs({1, 3}).NumOutputs(3);
 
 } // namespace caffe2
diff --git a/caffe2/contrib/fakelowp/test/test_layernorm_nnpi_fp16.py b/caffe2/contrib/fakelowp/test/test_layernorm_nnpi_fp16.py
index 698d7cd..920b3ff 100644
--- a/caffe2/contrib/fakelowp/test/test_layernorm_nnpi_fp16.py
+++ b/caffe2/contrib/fakelowp/test/test_layernorm_nnpi_fp16.py
@@ -63,7 +63,7 @@
         pred_net_ref.external_output.extend(["Y", "mean", "rstd"])
         pred_net_ref.op.add().CopyFrom(
             core.CreateOperator(
-                "LayerNormFakeFP16",
+                "LayerNormFakeFP16NNPI",
                 ["X", "gamma", "beta"],
                 ["Y", "mean", "rstd"],
                 axis=1,
diff --git a/caffe2/opt/custom/fakefp16_transform.cc b/caffe2/opt/custom/fakefp16_transform.cc
index 1427042..efd9c70 100644
--- a/caffe2/opt/custom/fakefp16_transform.cc
+++ b/caffe2/opt/custom/fakefp16_transform.cc
@@ -25,6 +25,7 @@
       {"Int8FC", "Int8FCFakeAcc32NNPI"},
       {"Int8Quantize", "Int8QuantizeNNPI"},
       {"Int8Dequantize", "Int8DequantizeNNPI"},
+      {"LayerNorm", "LayerNormFakeFP16NNPI"},
       {"FbFCPacked", "Fp16FCAcc32NNPI"},
       {"SparseLengthsSum", "SparseLengthsSumFakeFP16AccFP16"},
       {"SparseLengthsWeightedSum", "SparseLengthsWeightedSumFakeFP16AccFP16"},