From a34b6e38f3758722b88875f05c1c1198c8c94484 Mon Sep 17 00:00:00 2001
From: Mateusz Tabaka <mateusz.tabaka@intel.com>
Date: Fri, 18 Sep 2020 09:56:11 +0200
Subject: [PATCH] =?UTF-8?q?ConvertPrecision=20-=20saturate=20Constant's=20?=
 =?UTF-8?q?value=20to=20std::numeric=5Flimits<dst=E2=80=A6=20(#2206)?=
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* ConvertPrecision - saturate Constant's value to std::numeric_limits<dst_type>::lowest() if it's below that limit.

* Remove clamping to std::numeric_limits<int32_t>::lowest() in U32/U64 case
---
 .../src/transformations/convert_precision.cpp | 37 ++++++++---
 .../transformations/convert_precision.cpp     | 63 ++++++++++++++++++-
 2 files changed, 92 insertions(+), 8 deletions(-)

diff --git a/inference-engine/src/transformations/src/transformations/convert_precision.cpp b/inference-engine/src/transformations/src/transformations/convert_precision.cpp
index 132cf9691e5..41804a03057 100644
--- a/inference-engine/src/transformations/src/transformations/convert_precision.cpp
+++ b/inference-engine/src/transformations/src/transformations/convert_precision.cpp
@@ -297,8 +297,36 @@ bool extend_select_type(std::shared_ptr<ngraph::Node> & node, ngraph::element::T
     return false;
 }
 
+template <typename src_type, typename dst_type>
+inline dst_type convert_value(src_type val) {
+    if (val > std::numeric_limits<dst_type>::max()) {
+        return std::numeric_limits<dst_type>::max();
+    } else if (val < std::numeric_limits<dst_type>::lowest()) {
+        return std::numeric_limits<dst_type>::lowest();
+    }
+    return static_cast<dst_type>(val);
+}
+
+// We need to treat U64->I32 and U32->I32 as a separate case, because of C++'s implicit promotion from signed to unsigned,
+// and we don't need to compare and clamp the input to std::numeric_limits<int32_t>::lowest()
+template <>
+inline int32_t convert_value<uint64_t, int32_t>(uint64_t val) {
+    if (val > std::numeric_limits<int32_t>::max()) {
+        return std::numeric_limits<int32_t>::max();
+    }
+    return static_cast<int32_t>(val);
+}
+
+template <>
+inline int32_t convert_value<uint32_t, int32_t>(uint32_t val) {
+    if (val > std::numeric_limits<int32_t>::max()) {
+        return std::numeric_limits<int32_t>::max();
+    }
+    return static_cast<int32_t>(val);
+}
+
 template <element::Type_t PREC_FROM, element::Type_t PREC_TO>
-std::shared_ptr<Node> change_constant_precision(std::shared_ptr<opset4::Constant> & constant) {
+static std::shared_ptr<Node> change_constant_precision(std::shared_ptr<opset4::Constant>& constant) {
     using src_type = typename element_type_traits<PREC_FROM>::value_type;
     using dst_type = typename element_type_traits<PREC_TO>::value_type;
 
@@ -310,12 +338,7 @@ std::shared_ptr<Node> change_constant_precision(std::shared_ptr<opset4::Constant
 
     std::vector<dst_type> final_data;
     for (size_t i = 0; i < size; ++i) {
-        const auto & val = src_data[i];
-        if (val > std::numeric_limits<dst_type>::max()) {
-            dst_data[i] = std::numeric_limits<dst_type>::max();
-        } else {
-            dst_data[i] = static_cast<dst_type>(val);
-        }
+        dst_data[i] = convert_value<src_type, dst_type>(src_data[i]);
     }
     return new_constant;
 }
diff --git a/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp b/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp
index 6671f346296..d67d67d29ae 100644
--- a/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp
+++ b/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp
@@ -560,4 +560,65 @@ TEST(TransformationTests, ConvertPrecision_Variables) {
     }
 
     ASSERT_FALSE(has_type<ngraph::element::Type_t::f16>(f));
-}
\ No newline at end of file
+}
+
+template <typename From, typename To>
+void constant_convert_test(element::Type_t type_from, element::Type_t type_to, From value, To expected) {
+    std::shared_ptr<ngraph::Function> f(nullptr);
+    {
+        auto c = opset4::Constant::create(type_from, Shape{}, {value});
+        f = std::make_shared<Function>(NodeVector{c}, ParameterVector{});
+
+        pass::Manager manager;
+        manager.register_pass<ngraph::pass::ConvertPrecision>(type_from, type_to);
+        manager.run_passes(f);
+    }
+    auto ops = f->get_ordered_ops();
+    auto c = std::dynamic_pointer_cast<opset4::Constant>(ops[0]);
+    ASSERT_NE(c, nullptr);
+
+    auto actual = c->cast_vector<To>()[0];
+    ASSERT_EQ(expected, actual);
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_I64MinToI32) {
+    constant_convert_test(element::Type_t::i64, element::Type_t::i32,
+                        std::numeric_limits<int64_t>::min(),
+                        std::numeric_limits<int32_t>::min());
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_I64MaxToI32) {
+    constant_convert_test(element::Type_t::i64, element::Type_t::i32,
+                        std::numeric_limits<int64_t>::max(),
+                        std::numeric_limits<int32_t>::max());
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U64MinToI32) {
+    constant_convert_test(element::Type_t::u64, element::Type_t::i32,
+                        std::numeric_limits<uint64_t>::min(), 0);
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U64MaxToI32) {
+    constant_convert_test(element::Type_t::u64, element::Type_t::i32,
+                        std::numeric_limits<uint64_t>::max(),
+                        std::numeric_limits<int32_t>::max());
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U64ToI32) {
+    constant_convert_test(element::Type_t::u64, element::Type_t::i32, 42, 42);
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U32MinToI32) {
+    constant_convert_test(element::Type_t::u32, element::Type_t::i32,
+                        std::numeric_limits<uint32_t>::min(), 0);
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U32MaxToI32) {
+    constant_convert_test(element::Type_t::u32, element::Type_t::i32,
+                        std::numeric_limits<uint32_t>::max(),
+                        std::numeric_limits<int32_t>::max());
+}
+
+TEST(TransformationTests, ConvertPrecision_ConstantConversion_U32ToI32) {
+    constant_convert_test(element::Type_t::u32, element::Type_t::i32, 42, 42);
+}