[microNPU] Move optimization passes to be a module pass and ensure they

are running

Moves LayoutOptimizer and LUTOptimizer passes to be a module pass,
rather than a function pass. This is because it was found that these
passes were not running in the NPU compilation flow. In addition, a
test for both LayoutOptimizer and LUTOptimizer has been added to check
that the passes are running in the compilation pipeline of the NPU.

Change-Id: I5145c6f02eeb0daea3cdba56198e0804ec32f351

Author: lhutton1

python/tvm/relay/backend/contrib/ethosu/codegen.py

@@ -18,13 +18,13 @@
 
 import tvm
 from tvm import relay
+from tvm import ir
 from tvm.relay.backend.contrib.ethosu.tir.compiler import lower_to_tir
 from tvm.relay.backend.contrib.ethosu.tir.scheduler import copy_constants
 from tvm.relay.backend.contrib.ethosu.legalize import LegalizeEthosU
 from tvm.relay.backend.contrib.ethosu import tir_to_cs_translator
 from tvm.relay.backend.contrib.ethosu import util
 from tvm.relay.expr_functor import ExprMutator
-from tvm.ir.transform import Pass
 
 # pylint: disable=unused-import
 from tvm.relay.backend.contrib.ethosu.op import op_attrs
@@ -109,13 +109,11 @@ def visit_call(self, call: tvm.relay.expr.Call) -> tvm.relay.expr.Call:
         return new_call
 
 
-@relay.transform.function_pass(opt_level=1, name="LUTsOptimizer")
-class LUTsOptimizer(Pass):
+@ir.transform.module_pass(opt_level=1, name="LUTsOptimizer")
+class LUTsOptimizer:
     """Register LUTsOptimizer as a relay pass."""
 
-    def transform_function(
-        self, func: tvm.relay.function.Function, mod: tvm.IRModule, _
-    ) -> tvm.IRModule:
+    def transform_module(self, mod: tvm.ir.IRModule, _) -> tvm.IRModule:
         """Visit relay nodes in the given module.
 
         Parameters
@@ -131,7 +129,13 @@ def transform_function(
             New module with optimized LUTs.
         """
         assert len(mod.functions.items()) == 1, "Module can only contain one function."
-        return OptimizeLUTs().visit(func)
+        global_var, func = mod.functions.items()[0]
+        optimized_func = OptimizeLUTs().visit(func)
+        mod.update_func(global_var, optimized_func)
+        return mod
+
+    def __call__(self, *args, **kwargs):
+        pass
 
 
 class LayoutOptimization(ExprMutator):
@@ -247,19 +251,23 @@ def visit_call(self, call: tvm.relay.expr.Call) -> tvm.relay.expr.Call:
         return super().visit_call(call)
 
 
-@relay.transform.function_pass(opt_level=1, name="LayoutOptimizer")
-class LayoutOptimizer(Pass):
+@ir.transform.module_pass(opt_level=1, name="LayoutOptimizer")
+class LayoutOptimizer:
     """Register LayoutOptimizer as a Relay pass."""
 
-    def transform_function(
-        self, func: tvm.relay.function.Function, mod: tvm.IRModule, _
-    ) -> tvm.IRModule:
+    def transform_module(self, mod: tvm.ir.IRModule, _) -> tvm.IRModule:
         """A pass to optimize the layout of NPU operations. If both the
         producer and consumer of a tensor are NPU operators, then the
         layout is converted from NHWC to NHCWB16 as this is the layout NPU
         uses internally."""
         assert len(mod.functions.items()) == 1, "Module can only contain one function."
-        return LayoutOptimization().visit(func)
+        global_var, func = mod.functions.items()[0]
+        optimized_func = LayoutOptimization().visit(func)
+        mod.update_func(global_var, optimized_func)
+        return mod
+
+    def __call__(self, *args, **kwargs):
+        pass
 
 
 @tvm._ffi.register_func("relay.ext.ethos-u.constant_updater")

tests/python/contrib/test_ethosu/test_layout_optimizer.py

@@ -33,14 +33,17 @@
 from tvm import relay
 from tvm.relay.op.contrib.ethosu import partition_for_ethosu
 from tvm.relay.backend.contrib.ethosu.codegen import LayoutOptimizer
+from tvm.relay.backend.contrib.ethosu.codegen import relay_to_tir_func
 
 from . import infra
 
 
-def _run_pass(expr, relay_pass):
-    """Create IRModule and run Relay pass."""
+def _optimize(expr, optimize=True):
+    """Create IRModule and run layout optimizer pass."""
     mod = tvm.IRModule.from_expr(expr)
-    mod = relay_pass(mod)
+    mod = relay.transform.InferType()(mod)
+    if optimize:
+        mod = LayoutOptimizer()(mod)
     entry = mod["main"]
     return entry if isinstance(expr, relay.Function) else entry.body
 
@@ -111,8 +114,8 @@ def get_graph():
         )
         return relay.Function(relay.analysis.free_vars(x), x)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -144,8 +147,8 @@ def get_graph(get_expected=False):
             )
         return relay.Function(relay.analysis.free_vars(x), x)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -176,8 +179,8 @@ def get_graph(get_expected=False):
             )
         return relay.Function(relay.analysis.free_vars(x), x)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -222,8 +225,8 @@ def get_graph():
         )
         return relay.Function(relay.analysis.free_vars(conv_2), conv_2)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -268,8 +271,8 @@ def get_graph():
         )
         return relay.Function(relay.analysis.free_vars(conv_2), conv_2)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -322,8 +325,8 @@ def get_graph():
         )
         return relay.Function(relay.analysis.free_vars(pool_3), pool_3)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -368,8 +371,8 @@ def get_graph():
         )
         return relay.Function(relay.analysis.free_vars(conv), conv)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -413,8 +416,8 @@ def get_graph(get_expected=False):
         concat = relay.concatenate(poolings, axis=0)
         return relay.Function(relay.analysis.free_vars(concat), concat)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -467,8 +470,8 @@ def get_graph(get_expected=False):
         )
         return relay.Function(relay.analysis.free_vars(add_3), add_3)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -500,8 +503,8 @@ def get_graph(get_expected=False):
             )
         return relay.Function(relay.analysis.free_vars(x), x)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -530,8 +533,8 @@ def get_graph(get_expected=False):
             )
         return relay.Function(relay.analysis.free_vars(x), x)
 
-    a = _run_pass(get_graph(), LayoutOptimizer())
-    b = _run_pass(get_graph(get_expected=True), relay.transform.InferType())
+    a = _optimize(get_graph())
+    b = _optimize(get_graph(get_expected=True), optimize=False)
     _assert_structural_equal(a, b)
 
 
@@ -619,5 +622,32 @@ def representative_dataset():
     _compile_and_compare_model(create_model(), ifm_shape, dtype)
 
 
+def test_layout_optimizer_runs_in_compilation_pipeline():
+    """Checks that the layout optimization pass runs as part of the NPU compilation
+    pipeline."""
+
+    def get_graph():
+        x = relay.var("x", shape=(1, 4, 4, 4), dtype="int8")
+        for _ in range(2):
+            x = relay.nn.max_pool2d(x, layout="NHWC")
+
+        func = relay.Function(relay.analysis.free_vars(x), x)
+        return tvm.IRModule.from_expr(func)
+
+    mod = get_graph()
+    mod = partition_for_ethosu(mod)
+
+    external_gv_name = mod["main"].body.op.name_hint
+    external_func = mod[external_gv_name]
+    prim_func = relay_to_tir_func(external_func)
+
+    # Check for hints in the TIR prim func that the layout optimization pass has ran
+    ops = prim_func.body.body.seq
+    max_pool1, max_pool2 = ops
+
+    assert str(max_pool1.value.args[31]) == '"NHCWB16"'
+    assert str(max_pool2.value.args[14]) == '"NHCWB16"'
+
+
 if __name__ == "__main__":
     pytest.main([__file__] + sys.argv[1:])

tests/python/contrib/test_ethosu/test_lut_optimizer.py

@@ -21,9 +21,16 @@
 
 pytest.importorskip("ethosu.vela")
 
+import tensorflow as tf
+import numpy as np
+
 import tvm
 from tvm import relay
 from tvm.relay.backend.contrib.ethosu.codegen import LUTsOptimizer
+from tvm.relay.backend.contrib.ethosu.codegen import relay_to_tir_func
+from tvm.relay.op.contrib.ethosu import partition_for_ethosu
+
+from .test_codegen import _get_tflite_graph
 from . import infra
 
 
@@ -59,6 +66,7 @@ def after():
         return mod
 
     mod = LUTsOptimizer()(before())
+    mod = relay.transform.InferType()(mod)
 
     assert tvm.ir.structural_equal(mod, after())
 
@@ -91,5 +99,35 @@ def after():
         return mod
 
     mod = LUTsOptimizer()(before())
+    mod = relay.transform.InferType()(mod)
 
     assert tvm.ir.structural_equal(mod, after())
+
+
+def test_lut_optimizer_runs_in_compilation_pipeline():
+    """Test that the LUT optimization pass runs as part of the NPU compilation pipeline."""
+    ifm_shape = (1, 4, 4, 4)
+
+    @tf.function
+    def get_graph(x):
+        weight1 = tf.constant(np.random.uniform(size=(1, 1, 4, 4)), dtype=tf.float32)
+        op = tf.nn.conv2d(x, weight1, (1, 1), "VALID")
+        op = tf.nn.tanh(op)
+        weight2 = tf.constant(np.random.uniform(size=(1, 1, 4, 1)), dtype=tf.float32)
+        op = tf.nn.depthwise_conv2d(op, weight2, (1, 1, 1, 1), "VALID")
+        return tf.nn.tanh(op)
+
+    mod, _ = _get_tflite_graph(get_graph, [ifm_shape])
+    mod = partition_for_ethosu(mod)
+
+    external_gv_name = mod["main"].body.op.name_hint
+    external_func = mod[external_gv_name]
+    prim_func = relay_to_tir_func(external_func)
+
+    # Check for hints in the TIR prim func that the LUT optimization pass has ran.
+    # If the module was optimized, there should be no identity operations.
+    def check_identity(stmt):
+        if isinstance(stmt, tvm.tir.expr.Call):
+            assert stmt.args[0] != "ethosu_identity"
+
+    tvm.tir.stmt_functor.post_order_visit(prim_func.body, check_identity)