From 79126ece739c8a97b20a2d399a505ab0a6bd9494 Mon Sep 17 00:00:00 2001
From: Justin Lebar <jlebar@google.com>
Date: Wed, 26 Dec 2018 11:32:32 -0800
Subject: [PATCH] [XLA] Avoid fp division by 0 in literal_comparison.cc.

Found by running hlo_evaluator_test with ubsan.

PiperOrigin-RevId: 226937627
---
 tensorflow/compiler/xla/literal_comparison.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tensorflow/compiler/xla/literal_comparison.cc b/tensorflow/compiler/xla/literal_comparison.cc
index f4376d66af8..258bc966b1a 100644
--- a/tensorflow/compiler/xla/literal_comparison.cc
+++ b/tensorflow/compiler/xla/literal_comparison.cc
@@ -387,7 +387,14 @@ class NearComparator {
       rel_error = std::numeric_limits<float>::infinity();
     } else {
       abs_error = FpAbsoluteValue(actual - expected);
-      rel_error = abs_error / FpAbsoluteValue(expected);
+
+      // Avoid division by 0 even though it's well-defined because ubsan can be
+      // configured to treat this as a fatal error.
+      if (expected != T{0}) {
+        rel_error = abs_error / FpAbsoluteValue(expected);
+      } else {
+        rel_error = std::numeric_limits<float>::infinity();
+      }
     }
     const bool is_abs_mismatch = abs_error > error_.abs;
     const bool is_rel_mismatch = rel_error > error_.rel;