[clang] [Clang] Add __builtin_selectvector and use it for AVX512 intrinsics (PR #91306)

[Phoebe Wang via cfe-commits]

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@@ -41,6 +41,22 @@ typedef long long __m512i_u __attribute__((__vector_size__(64), __aligned__(1)))
 typedef unsigned char __mmask8;
 typedef unsigned short __mmask16;
 
+#ifdef __cplusplus
+typedef bool __vecmask2 __attribute__((__ext_vector_type__(2)));
+typedef bool __vecmask4 __attribute__((__ext_vector_type__(4)));
+typedef bool __vecmask8 __attribute__((__ext_vector_type__(8)));
+typedef bool __vecmask16 __attribute__((__ext_vector_type__(16)));
+typedef bool __vecmask32 __attribute__((__ext_vector_type__(32)));
+typedef bool __vecmask64 __attribute__((__ext_vector_type__(64)));
+#else
+typedef _Bool __vecmask2 __attribute__((__ext_vector_type__(2)));
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phoebewang wrote:

I'm a bit concerning about the ABI when people abuse them in function call.

https://github.com/llvm/llvm-project/pull/91306