From b99e54e05a4e9fed3bae1172c874af87e712526b Mon Sep 17 00:00:00 2001
From: SiCongLi <sicong.li@arm.com>
Date: Wed, 5 Jan 2022 12:18:03 +0000
Subject: Add signbit support for f16 type

Resolves COMPMID-5037

Change-Id: I648e8810dfd86e2ebcc16554f3f4cc58a5fd8c32
Signed-off-by: SiCongLi <sicong.li@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/6899
Reviewed-by: Giorgio Arena <giorgio.arena@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
---
 LICENSE                       |  2 +-
 support/ToolchainSupport.h    | 19 ++++++++++++++++++-
 tests/validation/Validation.h |  5 +++--
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/LICENSE b/LICENSE
index 1bb90563e9..953432d89e 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017-2021 Arm Limited
+Copyright (c) 2017-2022 Arm Limited
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/support/ToolchainSupport.h b/support/ToolchainSupport.h
index f19a8da627..cddcd542c8 100644
--- a/support/ToolchainSupport.h
+++ b/support/ToolchainSupport.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021 Arm Limited.
+ * Copyright (c) 2017-2022 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -309,6 +309,23 @@ inline bool isfinite(bfloat16 value)
 {
     return std::isfinite(float(value));
 }
+
+// std::signbit
+template <typename T, typename = typename std::enable_if<std::is_arithmetic<T>::value>::type>
+inline bool signbit(T value)
+{
+    return std::signbit(value);
+}
+
+inline bool signbit(half_float::half value)
+{
+    return half_float::signbit(value);
+}
+
+inline bool signbit(bfloat16 value)
+{
+    return std::signbit(float(value));
+}
 } // namespace cpp11
 } // namespace support
 } // namespace arm_compute
diff --git a/tests/validation/Validation.h b/tests/validation/Validation.h
index 7bad1a2286..289aca4d08 100644
--- a/tests/validation/Validation.h
+++ b/tests/validation/Validation.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021 Arm Limited.
+ * Copyright (c) 2017-2022 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -51,7 +51,8 @@ namespace
 template <typename T>
 inline bool are_equal_infs(T val0, T val1)
 {
-    return (!support::cpp11::isfinite(val0)) && (!support::cpp11::isfinite(val1)) && (std::signbit(val0) == std::signbit(val1));
+    const auto same_sign = support::cpp11::signbit(val0) == support::cpp11::signbit(val1);
+    return (!support::cpp11::isfinite(val0)) && (!support::cpp11::isfinite(val1)) && same_sign;
 }
 } // namespace
 
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