Support for DECODE operator (#3239)

* Support for DECODE operator

@tensorflow/micro

Add initial support for DECODE operator.
Add reference implementation.
Add LUT decompression support.
Update op resolvers.
Update Makefiles and Bazel BUILD files.
Add kernel unit test.

bug=fixes #3131

* update copyright

* Don't use constructors with global objects (bluepill will not call them).

Cleanup unit test.

* Support for DECODE operator

@tensorflow/micro

Additional support for DECODE operator.
Add Xtensa optimizations for LUT decompression.
Move all Xtensa kernel source references to the Xtensa target makefile.

bug=fixes #3150

* Updates to Xtensa makefiles

@tensorflow/micro

Reorganize Xtensa makefiles such that all references to optimized kernel sources are moved to the Xtensa target makefile.

Move hifimini kernel sources to the parent directory, and rename them so they do not interfere with the target overlay mechanism of the root makefile.

bug=fixes #3153

* Fix incorrect include path.
Fix code style errors.

* fix copyright

* update generic benchmark op resolver size

* Support for DECODE operator

@tensorflow/micro

Add reference implementation of pruning to DECODE operator.
Makefile and Bazel BUILD file changes.
Additional unit tests.

bug=fixes #3161

* Split decode tests into seperate files.
Update pruning code with zero-point checks.
Add const-tensor checks.

* Add decode_test_helpers.h file.
Cleanup tests.

* Support for DECODE operator

@tensorflow/micro

Add comprehensive DECODE unit test for LUT decompression.
Update decode_test_helpers.h with additional expected comparison tensor types.
Update Makefiles and Bazel build files.

* post review changes

---------

Co-authored-by: Esun Kim <veblush@google.com>

Author: ddavis-2015

tensorflow/lite/micro/kernels/BUILD

@@ -664,6 +664,22 @@ tflm_cc_test(
     ],
 )
 
+tflm_cc_test(
+    name = "decode_state_lut_test",
+    srcs = [
+        "decode_state_lut_test.cc",
+    ],
+    deps = [
+        ":decode_test_helpers",
+        ":kernel_runner",
+        "//tensorflow/lite/c:common",
+        "//tensorflow/lite/micro:debug_log",
+        "//tensorflow/lite/micro:op_resolvers",
+        "//tensorflow/lite/micro:test_helpers",
+        "//tensorflow/lite/micro/testing:micro_test",
+    ],
+)
+
 tflm_cc_test(
     name = "decode_state_prune_test",
     srcs = [

tensorflow/lite/micro/kernels/Makefile.inc

@@ -123,6 +123,7 @@ $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/ceil_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/comparisons_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/concatenation_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/cumsum_test.cc \
+$(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/decode_state_lut_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/decode_state_prune_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/decode_test.cc \
 $(TENSORFLOW_ROOT)tensorflow/lite/micro/kernels/depth_to_space_test.cc \