[XLA] Clean up some floating point printing code

- When doing *exact* floating point comparisons, print out enough digits of the
  floating point number to unambiguously round trip to the float in question.
- The exhaustive op test had an off-by-one for precision when printing a float.

PiperOrigin-RevId: 277988562
Change-Id: I9d30190a754d698e009fd51aa7fe6ca5661e2bc0

tensorflow/compiler/xla/literal_comparison.cc

@@ -16,6 +16,7 @@ limitations under the License.
 #include "tensorflow/compiler/xla/literal_comparison.h"
 
 #include <unistd.h>
+
 #include <cmath>
 #include <vector>
 
@@ -106,9 +107,9 @@ Status MakeBitwiseErrorStatus(NativeT lhs, NativeT rhs,
   auto rhs_double = static_cast<double>(rhs);
   return InvalidArgument(
       "floating values are not bitwise-equal; and equality testing "
-        "was requested: %s=%g=%a vs %s=%g=%a at array index %s",
-        StrCat(absl::Hex(ulhs)), lhs_double, lhs_double,
-        StrCat(absl::Hex(urhs)), rhs_double, rhs_double,
+      "was requested: %s=%s=%a vs %s=%s=%a at array index %s",
+      StrCat(absl::Hex(ulhs)), RoundTripFpToString(lhs), lhs_double,
+      StrCat(absl::Hex(urhs)), RoundTripFpToString(rhs), rhs_double,
       LiteralUtil::MultiIndexAsString(multi_index));
 }
 

tensorflow/compiler/xla/tests/exhaustive_op_test_utils.cc

@@ -37,7 +37,7 @@ struct ComponentStringifyFormat<double> {
 
 template <>
 struct ComponentStringifyFormat<float> {
-  static constexpr absl::string_view value = "%0.8g (0x%08x)";
+  static constexpr absl::string_view value = "%0.9g (0x%08x)";
 };
 
 template <>