[clang] [Headers][X86] Allow AVX512fp16 initialization intrinsics to be used in constexpr (PR #159929)

[Simon Pilgrim via cfe-commits]

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@@ -57,23 +58,23 @@ _mm256_set1_ph(_Float16 __h) {
                             __h, __h, __h, __h, __h, __h, __h, __h};
 }
 
-static __inline __m128h __DEFAULT_FN_ATTRS128
+static __inline __m128h __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_set_ph(_Float16 __h1, _Float16 __h2, _Float16 __h3, _Float16 __h4,
            _Float16 __h5, _Float16 __h6, _Float16 __h7, _Float16 __h8) {
   return (__m128h)(__v8hf){__h8, __h7, __h6, __h5, __h4, __h3, __h2, __h1};
 }
 
-static __inline __m256h __DEFAULT_FN_ATTRS256
+static __inline __m256h __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_set1_pch(_Float16 _Complex h) {
   return (__m256h)_mm256_set1_ps(__builtin_bit_cast(float, h));
 }
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RKSimon wrote:

test case?

https://github.com/llvm/llvm-project/pull/159929