[VPU][GT] Trivial permute optimization (#571)

* Transformation to eliminate trivial permute

* Minor changes in unit tests

* Replace trivial permutation with copy if input and output dims is equal

* Fix mergePermuteStages tests

* Small changes in the loop

* Add const modifier, change dimsVector type to SizeVector

* Change loop condition, rename valiable

* To reverse dimsVector

diff --git a/inference-engine/src/vpu/graph_transformer/src/middleend/passes/merge_permute_stages.cpp b/inference-engine/src/vpu/graph_transformer/src/middleend/passes/merge_permute_stages.cpp
index 05e0b36..4ca636b 100644 (file)
--- a/inference-engine/src/vpu/graph_transformer/src/middleend/passes/merge_permute_stages.cpp
+++ b/inference-engine/src/vpu/graph_transformer/src/middleend/passes/merge_permute_stages.cpp
@@ -55,11 +55,24 @@ private:
                                   permuteStage->output(0)->desc().dimsOrder());
     }
 
-    static bool isTrivialPermute(const PermutationIndexVector& permuteDims) {
-        for (size_t i = 0; i < permuteDims.size(); ++i)
-            if (i != permuteDims[i])
-                return false;
+    static bool isTrivialPermute(const PermutationIndexVector& permutation, const vpu::DimValues& dims) {
+        InferenceEngine::SizeVector dimsVector(dims.size());
+        for (const auto& dim : dims) {
+            auto index = dimToIeInd(dim.first, dims.size());
+            dimsVector[dims.size() - 1 - index] = dim.second;
+        }
 
+        for (size_t i = 0; i < permutation.size() - 1; ++i) {
+            if (i != permutation[i]) {
+                bool swapAdjacentDims = permutation[i] == (i + 1) && permutation[i + 1] == i;
+                bool dimIsOne = dimsVector[i] == 1 || dimsVector[i + 1] == 1;
+                if (swapAdjacentDims && dimIsOne) {
+                    i++;
+                } else {
+                    return false;
+                }
+            }
+        }
         return true;
     }
 
@@ -131,7 +144,6 @@ private:
 void PassImpl::run(const Model& model) {
     VPU_PROFILE(mergePermuteStages);
     const StageMergeGroupList stageMergeGroupList = prepareStagesForMerge(model);
-
     for (const auto& stageMergeGroup : stageMergeGroupList) {
         const auto& firstPermuteStage = stageMergeGroup.first;
         auto resultPermutation = permuteVectorFromStageInternal(firstPermuteStage);
@@ -157,8 +169,8 @@ void PassImpl::run(const Model& model) {
         if (!outputLayout.empty())
             firstPermuteStage->attrs().set(outputOrderKey, outputLayout);
 
-        // if we have no actual permutation, replace it with copy.
-        if (isTrivialPermute(resultPermutation)) {
+        // if we have no actual permutation, replace it with copy or reshape.
+        if (isTrivialPermute(resultPermutation, firstPermuteStage->input(0)->desc().dims())) {
             auto permuteInput  = firstPermuteStage->input(0);
             auto permuteOutput = firstPermuteStage->output(0);
             if (permuteInput->desc().dimsOrder() == permuteOutput->desc().dimsOrder()) {
@@ -166,10 +178,15 @@ void PassImpl::run(const Model& model) {
                 auto origLayer     = firstPermuteStage->origLayer();
                 model->removeStage(firstPermuteStage);
 
-                auto copyStage = _stageBuilder->addCopyStage(model, stageName + "@merged-to-copy",
-                                                             origLayer, permuteInput, permuteOutput, "Eliminated permute");
-                // TODO: make this optional=true with corresponding fixes in eliminate_copy (it expects Special stages now).
-                copyStage->attrs().set("optional", false);
+                if (permuteInput->desc().dims() == permuteOutput->desc().dims()) {
+                    auto copyStage = _stageBuilder->addCopyStage(model, stageName + "@merged-to-copy",
+                                                origLayer, permuteInput, permuteOutput, "Eliminated permute");
+                     // TODO: make this optional=true with corresponding fixes in eliminate_copy (it expects Special stages now).
+                    copyStage->attrs().set("optional", false);
+                } else {
+                    _stageBuilder->addReshapeStage(model, stageName + "@merged-to-reshape", origLayer,
+                                                    permuteInput, permuteOutput);
+                }
             }
         }
     }

diff --git a/inference-engine/tests_deprecated/functional/vpu/common/myriad_merge_permute_tests.hpp b/inference-engine/tests_deprecated/functional/vpu/common/myriad_merge_permute_tests.hpp
index ec0194d..dd5757d 100644 (file)
--- a/inference-engine/tests_deprecated/functional/vpu/common/myriad_merge_permute_tests.hpp
+++ b/inference-engine/tests_deprecated/functional/vpu/common/myriad_merge_permute_tests.hpp
@@ -79,26 +79,34 @@ TEST_P(myriadLayersMergePermuteNDTests_nightly, Permute) {
 }
 static const std::vector<InferenceEngine::SizeVector> s_inTensors_3D = {
     {5, 7, 11},
+    {1, 3, 4},
 };
 
 static const std::vector<PermutationsSequence> s_permuteParams_3D = {
+    {{0, 1, 2}, {1, 0, 2}}, // trivial for case with dims {1, 3, 4}
     {{1, 2, 0}, {1, 2, 0}},
     {{1, 2, 0}, {1, 2, 0}, {1, 2, 0}}, // trivial one.
 };
 
 static const std::vector<InferenceEngine::SizeVector> s_inTensors_4D = {
     {3, 5, 7, 11},
+    {5, 1, 1, 7},
 };
 
 static const std::vector<PermutationsSequence> s_permuteParams_4D = {
+    {{0, 1, 2, 3}, {1, 0, 3, 2}}, // 
+    {{0, 1, 2, 3}, {0, 1, 3, 2}}, // trivial for case with dims {5, 1, 1, 7}
     {{1, 2, 3, 0}, {1, 2, 3, 0}, {1, 2, 3, 0}},
     {{1, 2, 3, 0}, {1, 2, 3, 0}, {1, 2, 3, 0}, {1, 2, 3, 0}}, // trivial one.
 };
 
 static const std::vector<InferenceEngine::SizeVector> s_inTensors_5D = {
     {2, 3, 5, 7, 11},
+    {2, 3, 1, 7, 11},
 };
 static const std::vector<PermutationsSequence> s_permuteParams_5D = {
+    {{0, 1, 2, 3, 4}, {0, 1, 3, 2, 4}}, //
+    {{0, 1, 2, 3, 4}, {0, 2, 1, 3, 4}}, // trivial for case with dims {2, 3, 1, 7, 11}
     {{0, 4, 1, 2, 3}, {0, 2, 1, 3, 4}},
     {{0, 3, 4, 1, 2}, {0, 1, 3, 2, 4}},
     {{1, 2, 3, 4, 0}, {1, 2, 3, 4, 0}},