Adding an experimental/ path.

PiperOrigin-RevId: 292435170
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 78302f3..1c38314 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,8 +35,9 @@
 option(IREE_BUILD_SAMPLES "Builds IREE sample projects." ON)
 option(IREE_BUILD_DEBUGGER "Builds the IREE debugger app." OFF)
 option(IREE_BUILD_PYTHON_BINDINGS "Builds the IREE python bindings" OFF)
+option(IREE_BUILD_EXPERIMENTAL "Builds experimental projects." OFF)
 
-if(${IREE_BUILD_SAMPLES})
+if(${IREE_BUILD_SAMPLES} OR ${IREE_BUILD_EXPERIMENTAL})
   set(IREE_BUILD_COMPILER ON CACHE BOOL "Build the IREE compiler for sample projects." FORCE)
 endif()
 
@@ -187,3 +188,7 @@
 if(${IREE_BUILD_SAMPLES})
   add_subdirectory(iree/samples)
 endif()
+
+if(${IREE_BUILD_EXPERIMENTAL})
+  add_subdirectory(experimental)
+endif()
diff --git a/experimental/BUILD b/experimental/BUILD
new file mode 100644
index 0000000..a98a3c4
--- /dev/null
+++ b/experimental/BUILD
@@ -0,0 +1,18 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(
+    default_visibility = ["//visibility:public"],
+    licenses = ["notice"],  # Apache 2.0
+)
diff --git a/experimental/CMakeLists.txt b/experimental/CMakeLists.txt
new file mode 100644
index 0000000..d7282f2
--- /dev/null
+++ b/experimental/CMakeLists.txt
@@ -0,0 +1,17 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# NOTE: not all projects require a cmake build. If you are adding a directory
+# that is only expected to build with bazel (such as something depending on
+# TensorFlow) you can ignore cmake.
diff --git a/experimental/README.md b/experimental/README.md
new file mode 100644
index 0000000..57621d7
--- /dev/null
+++ b/experimental/README.md
@@ -0,0 +1,10 @@
+This folder contains experimental subprojects related to IREE and MLIR. These
+are not yet stable and supported and may not always be working. We ensure the
+build bots are green for the configurations the targets support but would prefer
+not to take on too much maintence overhead for things unless they are on a path
+to leaving experimental. Please use forks of the repository for purely
+experimental/personal work.
+
+**NOTE**: not all projects require a cmake build. If you are adding a directory
+that is only expected to build with bazel (such as something depending on
+TensorFlow) you can ignore cmake.