[clang] [Clang] feat: Allow AVX/AVX2 permute operations in constexpr (PR #172149)

[Simon Pilgrim via cfe-commits]

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@@ -462,15 +462,19 @@ let Features = "avx", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in
   def cvttpd2dq256 : X86Builtin<"_Vector<4, int>(_Vector<4, double>)">;
   def cvtpd2dq256 : X86Builtin<"_Vector<4, int>(_Vector<4, double>)">;
   def cvttps2dq256 : X86Builtin<"_Vector<8, int>(_Vector<8, float>)">;
-  def vperm2f128_pd256 : X86Builtin<"_Vector<4, double>(_Vector<4, double>, _Vector<4, double>, _Constant int)">;
-  def vperm2f128_ps256 : X86Builtin<"_Vector<8, float>(_Vector<8, float>, _Vector<8, float>, _Constant int)">;
-  def vperm2f128_si256 : X86Builtin<"_Vector<8, int>(_Vector<8, int>, _Vector<8, int>, _Constant int)">;
   foreach Op = ["max", "min"] in {
     def Op#pd256 : X86Builtin<"_Vector<4, double>(_Vector<4, double>, _Vector<4, double>)">;
     def Op#ps256 : X86Builtin<"_Vector<8, float>(_Vector<8, float>, _Vector<8, float>)">;
   }
 }
 
+let Features = "avx",
+    Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
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RKSimon wrote:

There are existing blocks with the same Features/Attributes combo - please add them to one of those

https://github.com/llvm/llvm-project/pull/172149