[clang] [X86] Allow PSHUFD/PSHUFLW/PSHUFW intrinsics in constexpr. (PR #161210)

[Simon Pilgrim via cfe-commits]

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@@ -11615,6 +11615,72 @@ static bool evalPackBuiltin(const CallExpr *E, EvalInfo &Info, APValue &Result,
   return true;
 }
 
+static bool evalPshufBuiltin(EvalInfo &Info, const CallExpr *Call,
+                             unsigned ElemBits, unsigned HalfBase,
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RKSimon wrote:

ElemBits should be determinable from VT

https://github.com/llvm/llvm-project/pull/161210