[XLA] Add format field to layout

Format will describe the method used to store array data in memory. Currently
only DENSE is supported, which represents the way XLA currently stores arrays.

Scalars have a DENSE format. Tuples and opaque shapes use INVALID_FORMAT.

Adds checks to code that uses minor_to_major to ensure the layout is dense.

PiperOrigin-RevId: 179475450

1 files changed, 9 insertions, 23 deletions

diff --git a/tensorflow/compiler/xla/shape_util_test.cc b/tensorflow/compiler/xla/shape_util_test.cc
index 4bce7ca51d..3be6d6c429 100644
--- a/tensorflow/compiler/xla/shape_util_test.cc
+++ b/tensorflow/compiler/xla/shape_util_test.cc
@@ -165,20 +165,6 @@ TEST(ShapeUtilTest, IncompatibleTuplesWithDifferentDimensions) {
   EXPECT_FALSE(ShapeUtil::Compatible(tuple1, tuple2));
 }
 
-TEST(ShapeUtilTest, EmptyLayoutEqualsMissingLayout) {
-  // A shape with a missing layout should be equal to a shape with an empty
-  // layout.
-  Shape scalar1 = ShapeUtil::MakeShape(F32, {});
-  Shape scalar2 = ShapeUtil::MakeShape(F32, {});
-
-  EXPECT_TRUE(ShapeUtil::Equal(scalar1, scalar2));
-
-  scalar1.clear_layout();    // Remove layout field.
-  scalar2.mutable_layout();  // Create empty layout field.
-
-  EXPECT_TRUE(ShapeUtil::Equal(scalar1, scalar2));
-}
-
 TEST(ShapeUtilTest, CompareShapesWithPaddedDimensionsMismatch) {
   Shape shape1 = ShapeUtil::MakeShape(F32, {20, 30});
   shape1.mutable_layout()->add_padded_dimensions(10);
@@ -199,17 +185,17 @@ TEST(ShapeUtilTest, CompareShapesWithPaddingValueMismatch) {
   EXPECT_FALSE(ShapeUtil::Equal(shape1, shape2));
 }
 
-TEST(ShapeUtilTest, ScalarUnpopulatedLayoutEqualsScalarLayout) {
-  Shape scalar_unpopulated = ShapeUtil::MakeShape(F32, {});
-  scalar_unpopulated.clear_layout();
-  ASSERT_FALSE(scalar_unpopulated.has_layout())
-      << ShapeUtil::HumanStringWithLayout(scalar_unpopulated);
+TEST(ShapeUtilTest, ScalarDefaultLayoutEqualsScalarEmptyMin2Maj) {
+  Shape scalar_default_layout = ShapeUtil::MakeShape(F32, {});
+  ASSERT_TRUE(scalar_default_layout.has_layout())
+      << ShapeUtil::HumanStringWithLayout(scalar_default_layout);
 
-  const Shape scalar_populated = ShapeUtil::MakeShapeWithLayout(F32, {}, {});
-  ASSERT_TRUE(scalar_populated.has_layout())
-      << ShapeUtil::HumanStringWithLayout(scalar_populated);
+  const Shape scalar_empty_min2maj =
+      ShapeUtil::MakeShapeWithLayout(F32, {}, {});
+  ASSERT_TRUE(scalar_empty_min2maj.has_layout())
+      << ShapeUtil::HumanStringWithLayout(scalar_empty_min2maj);
 
-  EXPECT_TRUE(ShapeUtil::Equal(scalar_unpopulated, scalar_populated));
+  EXPECT_TRUE(ShapeUtil::Equal(scalar_default_layout, scalar_empty_min2maj));
 }
 
 TEST(ShapeUtilTest, ByteSizeOfWithoutPadding) {