From 9a57678e2025fdeba421a0e572ce5535b604ae82 Mon Sep 17 00:00:00 2001
From: "zhongxiao.yzx" <yaozhongxiao@linux.alibaba.com>
Date: Wed, 12 May 2021 14:40:14 +0800
Subject: [PATCH] Fix is_vector_type fail while building neon with clang or GCC
 > 10.0

GCC with version 10 onward does not treat intrinsic type(int8x16_t)
and __vector_type(vector_size(16) int8_t) are the same which lead
to is_vector_type<Tp> failure.
Meanwhile, clang use __attribute__((neon_vector_type)) is not same
type with __attribute__((__vector_size__()))
Above all, is_vector_type should be judged by logical "or"
with the same<Tp, __vector_type> and same<Tp,__intrinsic_type>

ChangeLog:
  * experimental/bits/simd.h: refactor the is_vector_type taking
  vector_type and intrinsic_type as independent types
---
 experimental/bits/simd.h | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/experimental/bits/simd.h b/experimental/bits/simd.h
index 4c893114f..5482cea6e 100644
--- a/experimental/bits/simd.h
+++ b/experimental/bits/simd.h
@@ -1398,12 +1398,19 @@ template <typename _Tp, typename = void_t<>>
   struct __is_vector_type : false_type {};
 
 template <typename _Tp>
-  struct __is_vector_type<
-    _Tp, void_t<typename __vector_type<
-	   remove_reference_t<decltype(declval<_Tp>()[0])>, sizeof(_Tp)>::type>>
-    : is_same<_Tp, typename __vector_type<
-		     remove_reference_t<decltype(declval<_Tp>()[0])>,
-		     sizeof(_Tp)>::type> {};
+struct __is_vector_type<
+  _Tp,
+  enable_if_t<std::disjunction_v<
+    std::is_same<_Tp,
+		 typename __vector_type<typename std::remove_reference<decltype(
+					  std::declval<_Tp>()[0])>::type,
+					sizeof(_Tp)>::type>,
+    std::is_same<
+      _Tp, typename __intrinsic_type<typename std::remove_reference<decltype(
+				       std::declval<_Tp>()[0])>::type,
+				     sizeof(_Tp)>::type>>>> : true_type
+{
+};
 
 template <typename _Tp>
   inline constexpr bool __is_vector_type_v = __is_vector_type<_Tp>::value;