Fix int4 conversion (openvinotoolkit#4983)

* Fix int4 conversion * Simplify logic
itikhono · Mar 29, 2021 · de50ecf · de50ecf
1 parent 007078d
commit de50ecf
Show file tree

Hide file tree

Showing 2 changed files with 31 additions and 44 deletions.
diff --git a/inference-engine/src/transformations/src/transformations/convert_precision.cpp b/inference-engine/src/transformations/src/transformations/convert_precision.cpp
@@ -406,7 +406,7 @@ struct EnumClassHash {
  *    int4 [1011] -> int8 [00001011]
  *  * For signed types we copy all bits (except sign bit) to destination type and after
  *    that for negative values we set to 1 all higher bits:
- *    int4 [1011] -> int8 [11110011]
+ *    int4 [1011] -> int8 [11111011]
  *
  * @param src source value      !!! the type must be unsigned !!!
  * @param dst destination value !!! the type must be unsigned !!!
@@ -427,42 +427,29 @@ void convert_lp_value(const SRC& src, DST& dst, size_t src_offset, size_t src_si
     // dst     [10001111 00000100] offset 5 size 9
     // new_val [00000000 00000000]
     DST new_val = 0;
-    // If source type is signed
-    if (is_signed) {
-        // Get the sign of value
-        // sign [00000000]
-        // invert value in order to use XOR
-        SRC sign = (~(val >> (src_size - 1))) & 0b1;
-        // Calculate diff in order to clean bits which don't exist in the source value
-        // diff 5
-        size_t diff = sizeof(SRC)*8 - src_size + 1;
-        // Clean unnecessary bits
-        // val [10100000]
-        val = val << diff;
-        // val [00000101]
-        val = (val >> diff);
-
-        // Negative number
-        if (!sign) {
-            // val [11110101]
-            val |= (src_max << (diff - 1));
-            // new_val [00000001 11111111]
-            new_val = (sign << (dst_size - 1)) ^ (dst_max >> (sizeof(DST) * 8 - dst_size));
-            // new_val [00000001 11110101]
-            new_val &= (dst_max << sizeof(SRC)*8) | val;
-        } else {
-            // new_val [00000000 00000101]
-            new_val = val;
-        }
+
+    // Calculate diff in order to clean bits which don't exist in the source value
+    // diff 4
+    size_t diff = sizeof(SRC)*8 - src_size;
+    // Clean unnecessary bits
+    // val [11010000]
+    val = val << diff;
+    // val [00001101]
+    val = val >> diff;
+
+    // Get the sign of value
+    // sign [00000001]
+    SRC sign = (val >> (src_size - 1)) & 0b1;
+
+    // If source type is signed and negative
+    if (is_signed && sign) {
+        // val [11111101]
+        val |= src_max << diff;
+        // new_val [00000001 11111111]
+        new_val = dst_max >> (sizeof(DST) * 8 - dst_size);
+        // new_val [00000001 11111101]
+        new_val &= (dst_max << sizeof(SRC)*8) | val;
     } else {
-        // Calculate diff in order to clean bits which don't exist in the source value
-        // diff 4
-        size_t diff = sizeof(SRC)*8 - src_size;
-        // Clean unnecessary bits
-        // val [11010000]
-        val = val << diff;
-        // val [00001101]
-        val = val >> diff;
         // new_val [00000000 00001101]
         new_val = val;
     }

diff --git a/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp b/inference-engine/tests/functional/inference_engine/transformations/convert_precision.cpp
@@ -656,11 +656,11 @@ TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI8) {
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToU8_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::u8, 171, 242);
+    constant_convert_test(element::Type_t::i4, element::Type_t::u8, 171, 250);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI8_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::i8, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::i8, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_U4ToI32) {
@@ -680,11 +680,11 @@ TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI32) {
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToU32_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::u32, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::u32, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI32_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::i32, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::i32, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_U4ToI16) {
@@ -704,11 +704,11 @@ TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI16) {
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToU16_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::u16, 171, 65522);
+    constant_convert_test(element::Type_t::i4, element::Type_t::u16, 171, 65530);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI16_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::i16, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::i16, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_U4ToI64) {
@@ -728,11 +728,11 @@ TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI64) {
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToU64_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::u64, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::u64, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_I4ToI64_neg) {
-    constant_convert_test(element::Type_t::i4, element::Type_t::i64, 171, -14);
+    constant_convert_test(element::Type_t::i4, element::Type_t::i64, 171, -6);
 }
 
 TEST(TransformationTests, ConvertPrecision_ConstantConversion_U1ToU8) {