MLCE-753 Expand Tensorshape for relevent layers before verifying support

   Previously we were adding a reshape layer to "broadcast" tensors
   for elementwise operations. This broadcast was happening too late
   and was really just an expand dims. This was breaking the constant
   attributes of tensors and layer support of certain backends.

 * Remove addition of reshape layer when expanding dimensions
 * Replace broadcast function with expand dims to equal rank function
 * Fix some error status checks in various layers
 * Add new TensorUtil function that expands dims to a defined rank
 * Add unit tests to new TensorUtil function

Signed-off-by: Ryan OShea <ryan.oshea3@arm.com>
Change-Id: I31aca47c98075fef4f86864a15470f5faa55ab8d
diff --git a/src/armnnUtils/test/TensorUtilsTest.cpp b/src/armnnUtils/test/TensorUtilsTest.cpp
index a69a009..ed21bbe 100644
--- a/src/armnnUtils/test/TensorUtilsTest.cpp
+++ b/src/armnnUtils/test/TensorUtilsTest.cpp
@@ -126,11 +126,79 @@
     CHECK_THROWS_AS(ExpandDims(inputShape, 4), armnn::InvalidArgumentException);
 }
 
+TEST_CASE("ExpandDimsInvalidNegativeAxisTest")
+{
+    armnn::TensorShape inputShape({ 2, 3, 4 });
+
+    // Invalid expand dimension -5
+    CHECK_THROWS_AS(ExpandDims(inputShape, -5), armnn::InvalidArgumentException);
+}
+
+TEST_CASE("ExpandDimsBy1Rank")
+{
+    armnn::TensorShape inputShape({ 2, 3, 4 });
+
+    // Expand by 1 dimension
+    armnn::TensorShape outputShape = ExpandDimsToRank(inputShape, 4);
+    CHECK(outputShape.GetNumDimensions() == 4);
+    CHECK(outputShape[0] == 1);
+    CHECK(outputShape[1] == 2);
+    CHECK(outputShape[2] == 3);
+    CHECK(outputShape[3] == 4);
+}
+
+TEST_CASE("ExpandDimsBy2Ranks")
+{
+    armnn::TensorShape inputShape({ 3, 4 });
+
+    // Expand 2 dimensions
+    armnn::TensorShape outputShape = ExpandDimsToRank(inputShape, 4);
+    CHECK(outputShape.GetNumDimensions() == 4);
+    CHECK(outputShape[0] == 1);
+    CHECK(outputShape[1] == 1);
+    CHECK(outputShape[2] == 3);
+    CHECK(outputShape[3] == 4);
+}
+
+TEST_CASE("ExpandDimsBy3Ranks")
+{
+    armnn::TensorShape inputShape({ 4 });
+
+    // Expand 3 dimensions
+    armnn::TensorShape outputShape = ExpandDimsToRank(inputShape, 4);
+    CHECK(outputShape.GetNumDimensions() == 4);
+    CHECK(outputShape[0] == 1);
+    CHECK(outputShape[1] == 1);
+    CHECK(outputShape[2] == 1);
+    CHECK(outputShape[3] == 4);
+}
+
+TEST_CASE("ExpandDimsInvalidRankAmount")
+{
+    armnn::TensorShape inputShape({ 2, 3, 4 });
+
+    // Don't expand because target rank is smaller than current rank
+    armnn::TensorShape outputShape = ExpandDimsToRank(inputShape, 2);
+    CHECK(outputShape.GetNumDimensions() == 3);
+    CHECK(outputShape[0] == 2);
+    CHECK(outputShape[1] == 3);
+    CHECK(outputShape[2] == 4);
+}
+
+TEST_CASE("ExpandDimsToRankInvalidTensorShape")
+{
+    armnn::TensorShape inputShape({ 2, 3, 4 });
+
+    // Throw exception because rank 6 tensors are unsupported by armnn
+    CHECK_THROWS_AS(ExpandDimsToRank(inputShape, 6), armnn::InvalidArgumentException);
+}
+
+
 TEST_CASE("ReduceDimsShapeAll1s")
 {
     armnn::TensorShape inputShape({ 1, 1, 1 });
 
-    // Invalid expand dimension 4
+    // Reduce dimension 2
     armnn::TensorShape outputShape = ReduceDims(inputShape, 2);
     CHECK(outputShape.GetNumDimensions() == 2);
     CHECK(outputShape[0] == 1);
@@ -141,7 +209,7 @@
 {
     armnn::TensorShape inputShape({ 1, 2, 1 });
 
-    // Invalid expand dimension 4
+    // Reduce dimension 1
     armnn::TensorShape outputShape = ReduceDims(inputShape, 1);
     CHECK(outputShape.GetNumDimensions() == 2);
     CHECK(outputShape[0] == 2);
@@ -152,7 +220,7 @@
 {
     armnn::TensorInfo inputInfo({ 1, 1, 1 }, DataType::Float32);
 
-    // Invalid expand dimension 4
+    // Reduce dimension 2
     armnn::TensorInfo outputInfo = ReduceDims(inputInfo, 2);
     CHECK(outputInfo.GetShape().GetNumDimensions() == 2);
     CHECK(outputInfo.GetShape()[0] == 1);
@@ -163,7 +231,7 @@
 {
     armnn::TensorInfo inputInfo({ 1, 2, 1 }, DataType::Float32);
 
-    // Invalid expand dimension 4
+    // Reduce dimension 1
     armnn::TensorInfo outputInfo = ReduceDims(inputInfo, 1);
     CHECK(outputInfo.GetNumDimensions() == 2);
     CHECK(outputInfo.GetShape()[0] == 2);
@@ -174,7 +242,7 @@
 {
     armnn::TensorShape inputShape({ 1, 1, 1 });
 
-    // Invalid expand dimension 4
+    // Do not reduce because dimension does not exist
     armnn::TensorShape outputShape = ReduceDims(inputShape, 4);
     CHECK(outputShape.GetNumDimensions() == 3);
     CHECK(outputShape[0] == 1);
@@ -182,13 +250,6 @@
     CHECK(outputShape[2] == 1);
 }
 
-TEST_CASE("ExpandDimsInvalidNegativeAxisTest")
-{
-    armnn::TensorShape inputShape({ 2, 3, 4 });
-
-    // Invalid expand dimension -5
-    CHECK_THROWS_AS(ExpandDims(inputShape, -5), armnn::InvalidArgumentException);
-}
 
 TEST_CASE("ToFloatArrayInvalidDataType")
 {